Canvas transcript
Canvas transcript
Every bin/canvas invocation made while driving the canvas for Basecamp todo
10329619223 by hand. Verbatim command line, exit code, complete stdout and stderr,
appended as each one was run.
Store: OPENCLAW_WORKSPACE=/Users/lfigea/.openclaw/runs/bc-10326884731-deliver-the-first-priority-canvas-todo-d/canvas-store
Tool: /Users/lfigea/.openclaw/runs/bc-10326884731-deliver-the-first-priority-canvas-todo-d/canvas/bin/canvas
python3 bin/canvas create bc-10329619223-errno-decides-the-repository-refusals --problem The parent change made every refusal's exit code, its repair and whatever it claims about the store derive from the errno the operating system actually returned, rather than from the guard the failure happened to land in - but one refusal helper and one next-action template were left outside that rule. canvas/store.py:582 _cannot_read_repository returns ToolProblem, exit 2, for every errno including ENOENT, where its sibling _cannot_read now returns exit 1 for ENOENT. canvas/refusal.py _OS_NEXT_ACTION[errno.ENOENT] says ls -ld ` says which, and on a path that is genuinely gone that ls exits 1. --expected-value Every refusal helper in canvas/store.py that is handed an OSError chooses its exit code from the errno, _cannot_read_repository included - or README.md section Exit codes states, in its own words, why a repository that vanished is 2 where a canvas file that vanished is 1. A rule is settled and written down for whether a Canvas-Next: may name a command that exits non-zero. tests/test_store.py assertRepairsRun enforces whichever rule that settled. python3 -m unittest discover -s tests -t . passes from a clean tree, and the new behaviour fails against the code as it stands before the change - demonstrated, not asserted.`
exit: 0
Canvas-Base: e694e94ac22ec682e2c5cbd87de780ae94d0e720
Canvas-File: /Users/lfigea/.openclaw/runs/bc-10326884731-deliver-the-first-priority-canvas-todo-d/canvas-store/state/canvas/bc-10329619223-errno-decides-the-repository-refusals.xml
python3 bin/canvas read bc-10329619223-errno-decides-the-repository-refusals
exit: 0
Canvas-Base: e694e94ac22ec682e2c5cbd87de780ae94d0e720
<?xml version="1.0" encoding="UTF-8"?>
<canvas ledger="bc-10329619223-errno-decides-the-repository-refusals" schema="1">
<text id="bpx2" v="1">The parent change made every refusal's exit code, its repair and whatever it claims about the store derive from the errno the operating system actually returned, rather than from the guard the failure happened to land in - but one refusal helper and one next-action template were left outside that rule. canvas/store.py:582 _cannot_read_repository returns ToolProblem, exit 2, for every errno including ENOENT, where its sibling _cannot_read now returns exit 1 for ENOENT. canvas/refusal.py _OS_NEXT_ACTION[errno.ENOENT] says `ls -ld <path>` says which, and on a path that is genuinely gone that ls exits 1.</text>
<text id="bcr2" v="1">Every refusal helper in canvas/store.py that is handed an OSError chooses its exit code from the errno, _cannot_read_repository included - or README.md section Exit codes states, in its own words, why a repository that vanished is 2 where a canvas file that vanished is 1. A rule is settled and written down for whether a Canvas-Next: may name a command that exits non-zero. tests/test_store.py assertRepairsRun enforces whichever rule that settled. python3 -m unittest discover -s tests -t . passes from a clean tree, and the new behaviour fails against the code as it stands before the change - demonstrated, not asserted.</text>
</canvas>
python3 bin/canvas insert bc-10329619223-errno-decides-the-repository-refusals --into root --type section --title Open question 1 - is a repository that vanished a 2 where a canvas file that vanished is a 1? --why the todo leaves this genuinely undecided and says so: 'Decide which is right and make the code say so'. Filing it as a section so the question and the options it is weighed against sit together, rather than as loose siblings a later reader has to associate by adjacency. --base e694e94ac22ec682e2c5cbd87de780ae94d0e720
exit: 0
Canvas-Node: hp9p
Canvas-Base: 7fcaeff7cf159b227146b1833b7adbcb096545c0
python3 bin/canvas insert bc-10329619223-errno-decides-the-repository-refusals --into hp9p --type question --text Should _cannot_read_repository return exit 1 for ENOENT, the way its sibling _cannot_read now does, or is a repository that vanished genuinely a different kind of failure from a canvas file that vanished, and so still a 2? --why recording the question in the words the todo asks it in, before anything is decided. It is the one thing in Case 1 that is not mechanical: the five call sites are known, the errno table is known, and only this is open. --base 7fcaeff7cf159b227146b1833b7adbcb096545c0
exit: 0
Canvas-Node: t8zw
Canvas-Base: 94ce546047f018afabf9d583b85ee6bb55ba8d76
python3 bin/canvas insert bc-10329619223-errno-decides-the-repository-refusals --into hp9p --type table --why the options for question 1 and what each one costs, as a table, because this is the shape the replace verb is meant to settle into a decision later. Empty for one commit: the tool brings exactly one node per edit, so the table arrives before any row it will hold. --base 94ce546047f018afabf9d583b85ee6bb55ba8d76
exit: 0
Canvas-Node: uz6x
Canvas-Base: 8467e0fed0b0131c77478b8cefb0eb6f88b5a6d8
python3 bin/canvas insert bc-10329619223-errno-decides-the-repository-refusals --into uz6x --type row --why the header row: the table has two columns and nothing else in the vocabulary can say so, since a <table> carries no column names and a <cell> carries no header flag. --base 8467e0fed0b0131c77478b8cefb0eb6f88b5a6d8
exit: 0
Canvas-Node: s437
Canvas-Base: b7a301d82610b4400c54df6e51d6cc2d9b149bc8
python3 bin/canvas insert bc-10329619223-errno-decides-the-repository-refusals --into s437 --type cell --text Option --why column one names the option. A header cell is an ordinary <cell>; the vocabulary has no other kind, so 'this row is the header' is carried by its position and by nothing else. --base b7a301d82610b4400c54df6e51d6cc2d9b149bc8
exit: 0
Canvas-Node: sm4b
Canvas-Base: 525ab6623d09f7f54ca52e7bf77b17c05e60a2a6
python3 bin/canvas insert bc-10329619223-errno-decides-the-repository-refusals --into s437 --type cell --text What it costs --why column two is the cost, not the argument for it. The todo is explicit that this is a decision to be made, so what each route gives up is the thing worth having written down when somebody asks later why the other one was not taken. --base 525ab6623d09f7f54ca52e7bf77b17c05e60a2a6
exit: 0
Canvas-Node: zyrd
Canvas-Base: 65c03770b7add4766bb2a02681b40dde14a1fe40
python3 bin/canvas insert bc-10329619223-errno-decides-the-repository-refusals --into uz6x --type row --why option A's row. One row per option so that each one can be read, argued with and eventually struck out on its own. --base 65c03770b7add4766bb2a02681b40dde14a1fe40
exit: 0
Canvas-Node: fu7f
Canvas-Base: 28985c659c2b33619c4afc84ae714af3c8fd2d15
python3 bin/canvas insert bc-10329619223-errno-decides-the-repository-refusals --into r --type row --why x --base 28985c659c2b33619c4afc84ae714af3c8fd2d15
exit: 1
canvas: no node with id r in this canvas: nothing was changed
Canvas-Node: r
Canvas-About: ledger id bc-10329619223-errno-decides-the-repository-refusals
Canvas-About: position r
Canvas-Next: `bin/canvas read bc-10329619223-errno-decides-the-repository-refusals` prints the canvas and every id in it; re-run naming --after <node-id> or --into <container-id> from those, where 'root' names the canvas itself
Canvas-Exit: 1 — the request is wrong against the store as it stands; re-read and re-decide
python3 bin/canvas read bc-10329619223-errno-decides-the-repository-refusals
exit: 0
Canvas-Base: 28985c659c2b33619c4afc84ae714af3c8fd2d15
<?xml version="1.0" encoding="UTF-8"?>
<canvas ledger="bc-10329619223-errno-decides-the-repository-refusals" schema="1">
<text id="bpx2" v="1">The parent change made every refusal's exit code, its repair and whatever it claims about the store derive from the errno the operating system actually returned, rather than from the guard the failure happened to land in - but one refusal helper and one next-action template were left outside that rule. canvas/store.py:582 _cannot_read_repository returns ToolProblem, exit 2, for every errno including ENOENT, where its sibling _cannot_read now returns exit 1 for ENOENT. canvas/refusal.py _OS_NEXT_ACTION[errno.ENOENT] says `ls -ld <path>` says which, and on a path that is genuinely gone that ls exits 1.</text>
<text id="bcr2" v="1">Every refusal helper in canvas/store.py that is handed an OSError chooses its exit code from the errno, _cannot_read_repository included - or README.md section Exit codes states, in its own words, why a repository that vanished is 2 where a canvas file that vanished is 1. A rule is settled and written down for whether a Canvas-Next: may name a command that exits non-zero. tests/test_store.py assertRepairsRun enforces whichever rule that settled. python3 -m unittest discover -s tests -t . passes from a clean tree, and the new behaviour fails against the code as it stands before the change - demonstrated, not asserted.</text>
<section id="hp9p" v="1" title="Open question 1 - is a repository that vanished a 2 where a canvas file that vanished is a 1?">
<question id="t8zw" v="1">Should _cannot_read_repository return exit 1 for ENOENT, the way its sibling _cannot_read now does, or is a repository that vanished genuinely a different kind of failure from a canvas file that vanished, and so still a 2?</question>
<table id="uz6x" v="1">
<row id="s437" v="1">
<cell id="sm4b" v="1">Option</cell>
<cell id="zyrd" v="1">What it costs</cell>
</row>
<row id="fu7f" v="1"/>
</table>
</section>
</canvas>
python3 bin/canvas insert bc-10329619223-errno-decides-the-repository-refusals --into fu7f --type cell --text A. Classify by errno, exactly as _cannot_read does: ENOENT returns the exit-1 refusal, every other errno stays a ToolProblem at exit 2. --why the route the todo names first and the one the parent change's own rule points at. Writing it down as an option rather than as the answer, because the five call sites are not all alike and that is what has to be weighed. --base 28985c659c2b33619c4afc84ae714af3c8fd2d15
exit: 0
Canvas-Node: mkyr
Canvas-Base: f54cd5ad75f9f4ba66c53f8b9837b13cecd156ce
python3 bin/canvas insert bc-10329619223-errno-decides-the-repository-refusals --into fu7f --type cell --text The five call sites are not alike. is_repository's ENOENT is an absence the caller can act on - ensure_repository creates the repository on first use - so exit 1 and 're-read and re-decide' is a true instruction there. head_sha and the two --base call sites are reached after the repository was already looked at, so an ENOENT there is the store vanishing under a running command, and 're-read and re-decide' invites a retry against a store that is gone. Exit 1 also collapses 'there is no canvas for this ledger id' and 'there is no canvas repository at all' into one code, and those want different things done about them. --why the cost is the part a decision three weeks old is no longer able to reconstruct. Naming the call sites individually because 'classify by errno' sounds uniform and the five places it lands are not. --base f54cd5ad75f9f4ba66c53f8b9837b13cecd156ce
exit: 0
Canvas-Node: lgvs
Canvas-Base: 80216712c90910fe0ba04fdeb2f6a97a4e29f7c4
python3 bin/canvas insert bc-10329619223-errno-decides-the-repository-refusals --into uz6x --type row --why option B's row. The todo offers it explicitly as the other half of condition (1): 'or README.md section Exit codes states, in its own words, why a repository that vanished is 2 where a canvas file that vanished is 1'. --base 80216712c90910fe0ba04fdeb2f6a97a4e29f7c4
exit: 0
Canvas-Node: pjt3
Canvas-Base: a41ca418bec92cf10bb25296255372bb810b23a9
python3 bin/canvas insert bc-10329619223-errno-decides-the-repository-refusals --into pjt3 --type cell --text B. Leave every errno at exit 2 and put the reason in README.md section Exit codes: a canvas file that is not there is a true statement about the store, while a canvas repository that is not there is the tool's own environment missing, and exit 2 is the code for that. --why the todo treats this as a legitimate answer and not a cop-out, and it is: the two absences really are different kinds of thing. Recording it in the form condition (1) would accept, so that whoever settles this can take it without re-deriving the wording. --base a41ca418bec92cf10bb25296255372bb810b23a9
exit: 0
Canvas-Node: ymcz
Canvas-Base: 6e29a846ba54e0c1c2e95d0b7bca2988020e2310
python3 bin/canvas insert bc-10329619223-errno-decides-the-repository-refusals --into pjt3 --type cell --text Two sibling helpers, sitting 170 lines apart, with visibly different rules for the same errno, and only a paragraph of README holding the difference in place. Nothing in the code enforces it, so the next person doing this refactor removes the special case again - which is how it came to be left out of the parent change in the first place. It also leaves the refusal saying 'what that repository holds is still unknown' at exit 2 in the one case where the errno said plainly that it holds nothing, because it is not there. --why the cost of B is not the prose, it is that prose is the only thing enforcing it. Writing that down because it is the argument a reviewer will make and it should not have to be made twice. --base 6e29a846ba54e0c1c2e95d0b7bca2988020e2310
exit: 0
Canvas-Node: smym
Canvas-Base: 2f10783b4aaf8563cd69c2d6e7f1b93788028873
python3 bin/canvas insert bc-10329619223-errno-decides-the-repository-refusals --into uz6x --type row --why option C's row. Not in the todo, but it is the route somebody will propose in review once option A's unevenness is pointed out, and an option that is only argued down in a review comment is an option nobody can find later. --base 2f10783b4aaf8563cd69c2d6e7f1b93788028873
exit: 0
Canvas-Node: nyah
Canvas-Base: bd1f849ae3894c10283ad8c8e37892d01498f968
python3 bin/canvas insert bc-10329619223-errno-decides-the-repository-refusals --into nyah --type cell --text C. Split by call site: return exit 1 where the caller can act on the absence (is_repository) and exit 2 where it cannot (head_sha, the --base resolution, the ancestry check), by giving _cannot_read_repository a parameter that says which. --why naming the third route in full so it can be rejected on its merits rather than never considered. It is the obvious answer to option A's cost cell and it needs an answer of its own. --base bd1f849ae3894c10283ad8c8e37892d01498f968
exit: 0
Canvas-Node: fbym
Canvas-Base: 041147e2e29bcd476079da5c9c78d6f487ad958b
python3 bin/canvas insert bc-10329619223-errno-decides-the-repository-refusals --into nyah --type cell --text This is classification by the guard the failure landed in, which is exactly the rule the parent change was made to remove. The same errno on the same directory would come back as two different exit codes depending on which command the caller happened to run, and a caller cannot see which guard it is inside. It also puts a sixth parameter on a helper with five call sites, and every one of them has to get it right for the rule to hold. --why the cost here is that it re-introduces the thing the parent change closed. Saying so plainly, because from inside one call site it looks like the careful answer. --base 041147e2e29bcd476079da5c9c78d6f487ad958b
exit: 0
Canvas-Node: rt82
Canvas-Base: 4545dd3d824a65af1a58d6af1057bc72e11f04e4
python3 bin/canvas insert bc-10329619223-errno-decides-the-repository-refusals --into root --type section --title Open question 2 - may a Canvas-Next: line name a command that exits non-zero at all? --why Case 2 of the todo, kept in its own section and deliberately not worked on here. A different writer takes this half, so the canvas has to carry the question in a state they can pick up without reading this one's shell history. --base 4545dd3d824a65af1a58d6af1057bc72e11f04e4
exit: 0
Canvas-Node: y9hx
Canvas-Base: 2503e2c79d4900fa5abd24613a40287b13e552d5
python3 bin/canvas insert bc-10329619223-errno-decides-the-repository-refusals --into y9hx --type question --text May a Canvas-Next: name a command that exits non-zero at all? _OS_NEXT_ACTION[errno.ENOENT] says ls -ld ` says which, and on a path that is genuinely gone that ls exits 1. The repair in the same template - bin/canvas create ... - succeeds. So this is not a broken repair; it is whether a next action may ever be a diagnostic rather than a repair. --why quoting the todo's own framing, which is careful to say this is not a bug report: 'this is not a broken repair - it is the unanswered question of whether a Canvas-Next: may name a command that exits non-zero at all'. That distinction is the whole of the question and it is the first thing a paraphrase loses. --base 2503e2c79d4900fa5abd24613a40287b13e552d5`
exit: 0
Canvas-Node: mqxd
Canvas-Base: 921112727100c845c8ddf651216c5788cdf4a263
python3 bin/canvas insert bc-10329619223-errno-decides-the-repository-refusals --into y9hx --type table --why the options for question 2 and what each costs, in the same shape as question 1's so the two can be read the same way. Empty for one commit, as before. --base 921112727100c845c8ddf651216c5788cdf4a263
exit: 0
Canvas-Node: ehxj
Canvas-Base: 61ba4a95567f3b9aefa6f26c38693320d83ba451
python3 bin/canvas insert bc-10329619223-errno-decides-the-repository-refusals --into ehxj --type row --why the header row, matching question 1's two columns. Same shape, same reading. --base 61ba4a95567f3b9aefa6f26c38693320d83ba451
exit: 0
Canvas-Node: rysw
Canvas-Base: 96276cf41d242631c9ab8e21f72eecdc195198cd
python3 bin/canvas insert bc-10329619223-errno-decides-the-repository-refusals --into rysw --type cell --text Option --why column one, as above. --base 96276cf41d242631c9ab8e21f72eecdc195198cd
exit: 0
Canvas-Node: vp52
Canvas-Base: 2cfb511e81f777e4ca7c62005afeb116992a5f4c
python3 bin/canvas insert bc-10329619223-errno-decides-the-repository-refusals --into rysw --type cell --text What it costs --why column two, as above. --base 2cfb511e81f777e4ca7c62005afeb116992a5f4c
exit: 0
Canvas-Node: be5v
Canvas-Base: 45bd1480a23ee7a8dde06b0d2567cd666f60918e
python3 bin/canvas insert bc-10329619223-errno-decides-the-repository-refusals --into ehxj --type row --why option A's row: no, it may not. --base 45bd1480a23ee7a8dde06b0d2567cd666f60918e
exit: 0
Canvas-Node: vqpn
Canvas-Base: 8f38fae8806e88097f5c249bb6232dee8d88dc1e
python3 bin/canvas insert bc-10329619223-errno-decides-the-repository-refusals --into vqpn --type cell --text A. No. Every command a Canvas-Next: names must exit 0 when run against the state that produced the refusal. The ls -ld comes out of _OS_NEXT_ACTION[errno.ENOENT], and assertRepairsRun drops its chmod-only exemption and runs every command every template names. --why the strict reading, and the one condition (3) can be enforced mechanically: a test that runs every command and checks its status needs no list of which ones count. --base 8f38fae8806e88097f5c249bb6232dee8d88dc1e
exit: 0
Canvas-Node: zksk
Canvas-Base: 96cd4bf0cf32687834877d6bd79ad176092c890c
python3 bin/canvas insert bc-10329619223-errno-decides-the-repository-refusals --into vqpn --type cell --text A refusal can then only ever tell you to repair, never to look. The ls -ld on a missing path is not noise: its exit 1 and its 'No such file or directory' are the answer to which component of the path is gone, which is the thing a caller facing an ENOENT most wants to know and the thing bin/canvas cannot tell it. Dropping it means either finding a zero-exit way to ask the same question or accepting that the tool stops helping at the point the caller most needs it to. --why the cost of the strict rule is a real loss of information, not just a lost line of text. Saying which information, because 'we removed the ls' reads like tidying up. --base 96cd4bf0cf32687834877d6bd79ad176092c890c
exit: 0
Canvas-Node: qdvs
Canvas-Base: be92dabe7d83227086a6eaf02d7b891d2cb0639f
python3 bin/canvas insert bc-10329619223-errno-decides-the-repository-refusals --into ehxj --type row --why option B's row: yes, provided the reader can tell a diagnostic from a repair. --base be92dabe7d83227086a6eaf02d7b891d2cb0639f
exit: 0
Canvas-Node: yh66
Canvas-Base: 8c6da7949a05d561ef4fd396cbdf1ab64a6d33b2
python3 bin/canvas insert bc-10329619223-errno-decides-the-repository-refusals --into yh66 --type cell --text B. Yes, provided README.md section What a refusal prints says so and says how a caller tells the diagnostic from the repair - and provided the format carries that distinction somewhere a machine can read it, rather than leaving it to be inferred from the verb. --why the other half condition (2) offers, written with the part the todo leaves implicit made explicit: 'says how a caller tells them apart' is a change to the refusal format, not only to the README. --base 8c6da7949a05d561ef4fd396cbdf1ab64a6d33b2
exit: 0
Canvas-Node: vgke
Canvas-Base: 0cdd29fc0ece69208ebc8eba359eb153418cbfa5
python3 bin/canvas insert bc-10329619223-errno-decides-the-repository-refusals --into yh66 --type cell --text Canvas-Next: is one line of prose with no marker on it, so telling the two apart means inventing one - a second trailer, a prefix, or a structure the line does not currently have - and every existing template has to be classified against it. Short of that, assertRepairsRun keeps a hand-maintained list of which commands it is allowed to run, which is what the chmod-only exemption already is: the thing condition (3) was written to remove stays, wearing a justification. --why the cost of B is that 'write it down in the README' is not sufficient on its own, and that is easy to miss when reading condition (2) quickly. The test in condition (3) is what forces the distinction to be machine-readable or not to exist. --base 0cdd29fc0ece69208ebc8eba359eb153418cbfa5
exit: 0
Canvas-Node: lp37
Canvas-Base: 213a28076e4b51a5d5e08f23cbc77e48f3f8ddd3
python3 bin/canvas replace bc-10329619223-errno-decides-the-repository-refusals lgvs --type cell --text The five call sites are not alike, and worse: the same fact already has an exit code. _not_a_repository (canvas/store.py:352) is what fires when the check itself finds no .git, and it is exit 2 - reproduced: 'state/canvas is not a git repository, so it has no sha to write against', Canvas-Exit 2, and its next action says 'a read never writes one'. Re-running the read does not fix it; only create does. So sending the racy ENOENT to exit 1 makes the exit code depend on which side of a race the caller landed - the exact disease _nothing_at's docstring says must not happen ('a race is the only difference between them, and the refusal a caller gets should not depend on which side of it they landed'). It would also send that caller to 're-read and re-decide' against a store where re-reading provably raises the same thing. Separately: is_repository's ENOENT never reaches this helper at all, because FileNotFoundError is caught above it and answered False. --why the work made this cell wrong, not just thin. I wrote it saying option A's cost was that the five call sites are uneven; running the non-racy case showed the real cost, which is that _not_a_repository already answers 2 for the identical fact and exit 1 here would make the code a function of a race. Replacing rather than adding a note, because the old sentence would otherwise still be sitting there being the weaker argument. --base 213a28076e4b51a5d5e08f23cbc77e48f3f8ddd3
exit: 0
Canvas-Node: lgvs
Canvas-Base: 5fa80e6b1ed52cf7cd0bc88ab28aaa1504a43438
python3 bin/canvas insert bc-10329619223-errno-decides-the-repository-refusals --after t8zw --type text --text Observed, before anything was changed. Both routes the todo names were run. EACCES (chmod 000 on .git) gives exit 2 and that is right. The vanished-repository route - .git removed between is_repository's os.stat and head_sha's rev-parse, simulated the way the parent todo's test does - gives exit 2 with 'cannot tell whether there are any commits in <dir>: looking at it was refused: [Errno 2] No such file or directory', an aftermath of 'what that repository holds is still unknown', a Canvas-About of 'errno 2 ENOENT', and a Canvas-Next whose repair is 'bin/canvas create <ledger-id> ...' - immediately under a Canvas-Exit that reads 'do not touch the canvas'. The exit code is arguable. Those last two lines are not: on ENOENT the tool can tell, it does know what the repository holds (nothing, because there is none), and a refusal that names a bin/canvas command as the repair cannot in the same breath say do not touch the canvas. --why putting the reproduction in the canvas rather than only in a shell scrollback, because it changes what the question is. I came to this expecting to argue about 1 versus 2 and found two sentences that are false at either code. Placed directly under the question with --after, so a reader meets the evidence before the options it is supposed to weigh. --base 5fa80e6b1ed52cf7cd0bc88ab28aaa1504a43438
exit: 0
Canvas-Node: bv2j
Canvas-Base: a78e2256054cd67857530ce80fbb637926c87700
python3 bin/canvas insert bc-10329619223-errno-decides-the-repository-refusals --into hp9p --type text --text Where Case 1's code now stands, on branch errno-on-repository-refusals. _cannot_read_repository branches on errno.ENOENT and returns a new helper, _no_repository_at, which gives _not_a_repository's claim and _not_a_repository's repair in _not_a_repository's words - and at _not_a_repository's exit 2. So the option taken in code is B: a repository that vanished is a 2 where a canvas file that vanished is a 1, and README.md section Exit codes now says why in its own words. What the errno changed is what the tool says, not the code it exits with. EACCES is untouched and still says it cannot tell, because there the look really did fail. This node records what the code does; it does not close the question above it, which is still open and still carries all three options. --why the code moved and the canvas has to say so, or the next writer reads three open options and a green branch and cannot tell which of them is already in the tree. Writing it as a statement of where the code stands rather than as the decision, because the decision node is not mine to make here - the options table is still standing and a later pass settles it with replace. --base a78e2256054cd67857530ce80fbb637926c87700
exit: 0
Canvas-Node: nf98
Canvas-Base: 35e25a196f324f74ac8ba9321a17359716ecc6a1
python3 bin/canvas insert bc-10329619223-errno-decides-the-repository-refusals --into y9hx --type text --text For whoever takes Case 2: the reproduce command in the todo does not print what it says it does. python3 bin/canvas read no-such-ledger 2>&1 | grep ‘Canvas-Next:’ prints _nothing_at's next action - "create it with bin/canvas create no-such-ledger ..." - and no ls at all, because that path never goes through refusal.os_next_action. _OS_NEXT_ACTION[errno.ENOENT] is reached from canvas/store.py lines 165, 316, 479 and 1189 (and, until Case 1's change, 594). Case 1's change removes one of those five; the other four are untouched, so Case 2 is still fully reproducible - but not by the command the todo gives. --why found while checking that Case 1's change did not quietly settle Case 2 for the other writer. It does not, and the count is the evidence. Recording the todo's own reproduce command being wrong here rather than only in my head, because the next writer will run it first, get a Canvas-Next with no ls in it, and lose an hour deciding whether somebody already fixed this. --base 35e25a196f324f74ac8ba9321a17359716ecc6a1
exit: 0
Canvas-Node: echr
Canvas-Base: fe84545e1f040a9ec961013c79e4b8d3afe965b9
python3 bin/canvas insert bc-10329619223-errno-decides-the-repository-refusals --after bcr2 --type text --text Branch base, and it is not main. Everything this todo cites exists only on origin/errors/actionable-refusal-surface, the branch of the still-open PR #8 for the parent todo 10326884685. On main there is no canvas/refusal.py at all, and canvas/store.py contains neither _cannot_read_repository nor _cannot_read - checked by git ls-tree and git show, both counts zero. So errno-on-repository-refusals is cut from origin/errors/actionable-refusal-surface at cd8d90e, and any half of this work branched from main names files that are not there. The suite on that branch is 263 tests, not main's 189. --why the launch brief for this half said to branch from main, and branching from main would have produced a change to a function that does not exist there. Under guidelines/correction-authority.md the brief is the lowest authority and the todo description is higher, and the description cites canvas/store.py:582 by line - so the description wins and the base is PR #8's branch. Putting it at the top of the canvas because it is the first thing that would waste anybody else's afternoon. --base fe84545e1f040a9ec961013c79e4b8d3afe965b9
exit: 0
Canvas-Node: fdzu
Canvas-Base: 7a5b1f98ba026023ffd637b9ae0701252670f02f
python3 bin/canvas read bc-10329619223-errno-decides-the-repository-refusals
exit: 0
Canvas-Base: 7a5b1f98ba026023ffd637b9ae0701252670f02f
<?xml version="1.0" encoding="UTF-8"?>
<canvas ledger="bc-10329619223-errno-decides-the-repository-refusals" schema="1">
<text id="bpx2" v="1">The parent change made every refusal's exit code, its repair and whatever it claims about the store derive from the errno the operating system actually returned, rather than from the guard the failure happened to land in - but one refusal helper and one next-action template were left outside that rule. canvas/store.py:582 _cannot_read_repository returns ToolProblem, exit 2, for every errno including ENOENT, where its sibling _cannot_read now returns exit 1 for ENOENT. canvas/refusal.py _OS_NEXT_ACTION[errno.ENOENT] says `ls -ld <path>` says which, and on a path that is genuinely gone that ls exits 1.</text>
<text id="bcr2" v="1">Every refusal helper in canvas/store.py that is handed an OSError chooses its exit code from the errno, _cannot_read_repository included - or README.md section Exit codes states, in its own words, why a repository that vanished is 2 where a canvas file that vanished is 1. A rule is settled and written down for whether a Canvas-Next: may name a command that exits non-zero. tests/test_store.py assertRepairsRun enforces whichever rule that settled. python3 -m unittest discover -s tests -t . passes from a clean tree, and the new behaviour fails against the code as it stands before the change - demonstrated, not asserted.</text>
<text id="fdzu" v="1">Branch base, and it is not main. Everything this todo cites exists only on origin/errors/actionable-refusal-surface, the branch of the still-open PR #8 for the parent todo 10326884685. On main there is no canvas/refusal.py at all, and canvas/store.py contains neither _cannot_read_repository nor _cannot_read - checked by git ls-tree and git show, both counts zero. So errno-on-repository-refusals is cut from origin/errors/actionable-refusal-surface at cd8d90e, and any half of this work branched from main names files that are not there. The suite on that branch is 263 tests, not main's 189.</text>
<section id="hp9p" v="1" title="Open question 1 - is a repository that vanished a 2 where a canvas file that vanished is a 1?">
<question id="t8zw" v="1">Should _cannot_read_repository return exit 1 for ENOENT, the way its sibling _cannot_read now does, or is a repository that vanished genuinely a different kind of failure from a canvas file that vanished, and so still a 2?</question>
<text id="bv2j" v="1">Observed, before anything was changed. Both routes the todo names were run. EACCES (chmod 000 on .git) gives exit 2 and that is right. The vanished-repository route - .git removed between is_repository's os.stat and head_sha's rev-parse, simulated the way the parent todo's test does - gives exit 2 with 'cannot tell whether there are any commits in <dir>: looking at it was refused: [Errno 2] No such file or directory', an aftermath of 'what that repository holds is still unknown', a Canvas-About of 'errno 2 ENOENT', and a Canvas-Next whose repair is 'bin/canvas create <ledger-id> ...' - immediately under a Canvas-Exit that reads 'do not touch the canvas'. The exit code is arguable. Those last two lines are not: on ENOENT the tool can tell, it does know what the repository holds (nothing, because there is none), and a refusal that names a bin/canvas command as the repair cannot in the same breath say do not touch the canvas.</text>
<table id="uz6x" v="1">
<row id="s437" v="1">
<cell id="sm4b" v="1">Option</cell>
<cell id="zyrd" v="1">What it costs</cell>
</row>
<row id="fu7f" v="1">
<cell id="mkyr" v="1">A. Classify by errno, exactly as _cannot_read does: ENOENT returns the exit-1 refusal, every other errno stays a ToolProblem at exit 2.</cell>
<cell id="lgvs" v="2">The five call sites are not alike, and worse: the same fact already has an exit code. _not_a_repository (canvas/store.py:352) is what fires when the check itself finds no .git, and it is exit 2 - reproduced: 'state/canvas is not a git repository, so it has no sha to write against', Canvas-Exit 2, and its next action says 'a read never writes one'. Re-running the read does not fix it; only create does. So sending the racy ENOENT to exit 1 makes the exit code depend on which side of a race the caller landed - the exact disease _nothing_at's docstring says must not happen ('a race is the only difference between them, and the refusal a caller gets should not depend on which side of it they landed'). It would also send that caller to 're-read and re-decide' against a store where re-reading provably raises the same thing. Separately: is_repository's ENOENT never reaches this helper at all, because FileNotFoundError is caught above it and answered False.</cell>
</row>
<row id="pjt3" v="1">
<cell id="ymcz" v="1">B. Leave every errno at exit 2 and put the reason in README.md section Exit codes: a canvas file that is not there is a true statement about the store, while a canvas repository that is not there is the tool's own environment missing, and exit 2 is the code for that.</cell>
<cell id="smym" v="1">Two sibling helpers, sitting 170 lines apart, with visibly different rules for the same errno, and only a paragraph of README holding the difference in place. Nothing in the code enforces it, so the next person doing this refactor removes the special case again - which is how it came to be left out of the parent change in the first place. It also leaves the refusal saying 'what that repository holds is still unknown' at exit 2 in the one case where the errno said plainly that it holds nothing, because it is not there.</cell>
</row>
<row id="nyah" v="1">
<cell id="fbym" v="1">C. Split by call site: return exit 1 where the caller can act on the absence (is_repository) and exit 2 where it cannot (head_sha, the --base resolution, the ancestry check), by giving _cannot_read_repository a parameter that says which.</cell>
<cell id="rt82" v="1">This is classification by the guard the failure landed in, which is exactly the rule the parent change was made to remove. The same errno on the same directory would come back as two different exit codes depending on which command the caller happened to run, and a caller cannot see which guard it is inside. It also puts a sixth parameter on a helper with five call sites, and every one of them has to get it right for the rule to hold.</cell>
</row>
</table>
<text id="nf98" v="1">Where Case 1's code now stands, on branch errno-on-repository-refusals. _cannot_read_repository branches on errno.ENOENT and returns a new helper, _no_repository_at, which gives _not_a_repository's claim and _not_a_repository's repair in _not_a_repository's words - and at _not_a_repository's exit 2. So the option taken in code is B: a repository that vanished is a 2 where a canvas file that vanished is a 1, and README.md section Exit codes now says why in its own words. What the errno changed is what the tool says, not the code it exits with. EACCES is untouched and still says it cannot tell, because there the look really did fail. This node records what the code does; it does not close the question above it, which is still open and still carries all three options.</text>
</section>
<section id="y9hx" v="1" title="Open question 2 - may a Canvas-Next: line name a command that exits non-zero at all?">
<question id="mqxd" v="1">May a Canvas-Next: name a command that exits non-zero at all? _OS_NEXT_ACTION[errno.ENOENT] says `ls -ld <path>` says which, and on a path that is genuinely gone that ls exits 1. The repair in the same template - bin/canvas create ... - succeeds. So this is not a broken repair; it is whether a next action may ever be a diagnostic rather than a repair.</question>
<table id="ehxj" v="1">
<row id="rysw" v="1">
<cell id="vp52" v="1">Option</cell>
<cell id="be5v" v="1">What it costs</cell>
</row>
<row id="vqpn" v="1">
<cell id="zksk" v="1">A. No. Every command a Canvas-Next: names must exit 0 when run against the state that produced the refusal. The `ls -ld` comes out of _OS_NEXT_ACTION[errno.ENOENT], and assertRepairsRun drops its chmod-only exemption and runs every command every template names.</cell>
<cell id="qdvs" v="1">A refusal can then only ever tell you to repair, never to look. The `ls -ld` on a missing path is not noise: its exit 1 and its 'No such file or directory' are the answer to which component of the path is gone, which is the thing a caller facing an ENOENT most wants to know and the thing bin/canvas cannot tell it. Dropping it means either finding a zero-exit way to ask the same question or accepting that the tool stops helping at the point the caller most needs it to.</cell>
</row>
<row id="yh66" v="1">
<cell id="vgke" v="1">B. Yes, provided README.md section What a refusal prints says so and says how a caller tells the diagnostic from the repair - and provided the format carries that distinction somewhere a machine can read it, rather than leaving it to be inferred from the verb.</cell>
<cell id="lp37" v="1">Canvas-Next: is one line of prose with no marker on it, so telling the two apart means inventing one - a second trailer, a prefix, or a structure the line does not currently have - and every existing template has to be classified against it. Short of that, assertRepairsRun keeps a hand-maintained list of which commands it is allowed to run, which is what the chmod-only exemption already is: the thing condition (3) was written to remove stays, wearing a justification.</cell>
</row>
</table>
<text id="echr" v="1">For whoever takes Case 2: the reproduce command in the todo does not print what it says it does. `python3 bin/canvas read no-such-ledger 2>&1 | grep 'Canvas-Next:'` prints _nothing_at's next action - "create it with bin/canvas create no-such-ledger ..." - and no ls at all, because that path never goes through refusal.os_next_action. _OS_NEXT_ACTION[errno.ENOENT] is reached from canvas/store.py lines 165, 316, 479 and 1189 (and, until Case 1's change, 594). Case 1's change removes one of those five; the other four are untouched, so Case 2 is still fully reproducible - but not by the command the todo gives.</text>
</section>
</canvas>
python3 bin/canvas replace bc-10329619223-errno-decides-the-repository-refusals echr --type text --text For whoever takes Case 2, corrected - my first version of this node had the count wrong. Two things. (i) The reproduce command in the todo does not print what it says it does: python3 bin/canvas read no-such-ledger 2>&1 | grep ‘Canvas-Next:’ prints _nothing_at's next action, "create it with bin/canvas create no-such-ledger ...", and no ls at all, because that path never reaches refusal.os_next_action. (ii) _OS_NEXT_ACTION[errno.ENOENT] is reachable from far fewer places than grepping for os_next_action suggests. store.py has six calls to it, but four of them sit under an except OSError that a separate except FileNotFoundError above has already taken ENOENT away from - _no_canvas, the OPENCLAW_WORKSPACE stat, _write_and_commit's pre-write stat, and now _cannot_read_repository. Checked empirically, not by reading: spying on refusal.os_next_action and handing each helper a FileNotFoundError, exactly one errno 2 got through, from _cannot_write. So before Case 1's change the template had two reachable sites in store.py and now it has one, and that one is _cannot_write - which says in its own docstring that it is exit 2 for every errno, ENOENT included. Its Canvas-Next is the ls -ld <state/canvas> one. Case 2 is still live and still testable, including directly at the helper, the way test_an_unclassified_errno_still_refuses_in_the_shape already does. --why I wrote this node an hour ago off a grep for os_next_action and named four surviving call sites. Three of those four catch FileNotFoundError separately before the line I counted, so ENOENT never arrives there - checked by spying on the function rather than by reading the code again, because reading the code again is what produced the wrong count. Replacing rather than appending a correction, because the wrong number is the kind of thing a reader takes and acts on, and leaving it visible with a retraction under it is worse than one true sentence. --base 7a5b1f98ba026023ffd637b9ae0701252670f02f
exit: 0
Canvas-Node: echr
Canvas-Base: e950b24a9d809d1be42a551c26c37b58fdf5380c
python3 bin/canvas read bc-10329619223-errno-decides-the-repository-refusals
exit: 0
Canvas-Base: e950b24a9d809d1be42a551c26c37b58fdf5380c
<?xml version="1.0" encoding="UTF-8"?>
<canvas ledger="bc-10329619223-errno-decides-the-repository-refusals" schema="1">
<text id="bpx2" v="1">The parent change made every refusal's exit code, its repair and whatever it claims about the store derive from the errno the operating system actually returned, rather than from the guard the failure happened to land in - but one refusal helper and one next-action template were left outside that rule. canvas/store.py:582 _cannot_read_repository returns ToolProblem, exit 2, for every errno including ENOENT, where its sibling _cannot_read now returns exit 1 for ENOENT. canvas/refusal.py _OS_NEXT_ACTION[errno.ENOENT] says `ls -ld <path>` says which, and on a path that is genuinely gone that ls exits 1.</text>
<text id="bcr2" v="1">Every refusal helper in canvas/store.py that is handed an OSError chooses its exit code from the errno, _cannot_read_repository included - or README.md section Exit codes states, in its own words, why a repository that vanished is 2 where a canvas file that vanished is 1. A rule is settled and written down for whether a Canvas-Next: may name a command that exits non-zero. tests/test_store.py assertRepairsRun enforces whichever rule that settled. python3 -m unittest discover -s tests -t . passes from a clean tree, and the new behaviour fails against the code as it stands before the change - demonstrated, not asserted.</text>
<text id="fdzu" v="1">Branch base, and it is not main. Everything this todo cites exists only on origin/errors/actionable-refusal-surface, the branch of the still-open PR #8 for the parent todo 10326884685. On main there is no canvas/refusal.py at all, and canvas/store.py contains neither _cannot_read_repository nor _cannot_read - checked by git ls-tree and git show, both counts zero. So errno-on-repository-refusals is cut from origin/errors/actionable-refusal-surface at cd8d90e, and any half of this work branched from main names files that are not there. The suite on that branch is 263 tests, not main's 189.</text>
<section id="hp9p" v="1" title="Open question 1 - is a repository that vanished a 2 where a canvas file that vanished is a 1?">
<question id="t8zw" v="1">Should _cannot_read_repository return exit 1 for ENOENT, the way its sibling _cannot_read now does, or is a repository that vanished genuinely a different kind of failure from a canvas file that vanished, and so still a 2?</question>
<text id="bv2j" v="1">Observed, before anything was changed. Both routes the todo names were run. EACCES (chmod 000 on .git) gives exit 2 and that is right. The vanished-repository route - .git removed between is_repository's os.stat and head_sha's rev-parse, simulated the way the parent todo's test does - gives exit 2 with 'cannot tell whether there are any commits in <dir>: looking at it was refused: [Errno 2] No such file or directory', an aftermath of 'what that repository holds is still unknown', a Canvas-About of 'errno 2 ENOENT', and a Canvas-Next whose repair is 'bin/canvas create <ledger-id> ...' - immediately under a Canvas-Exit that reads 'do not touch the canvas'. The exit code is arguable. Those last two lines are not: on ENOENT the tool can tell, it does know what the repository holds (nothing, because there is none), and a refusal that names a bin/canvas command as the repair cannot in the same breath say do not touch the canvas.</text>
<table id="uz6x" v="1">
<row id="s437" v="1">
<cell id="sm4b" v="1">Option</cell>
<cell id="zyrd" v="1">What it costs</cell>
</row>
<row id="fu7f" v="1">
<cell id="mkyr" v="1">A. Classify by errno, exactly as _cannot_read does: ENOENT returns the exit-1 refusal, every other errno stays a ToolProblem at exit 2.</cell>
<cell id="lgvs" v="2">The five call sites are not alike, and worse: the same fact already has an exit code. _not_a_repository (canvas/store.py:352) is what fires when the check itself finds no .git, and it is exit 2 - reproduced: 'state/canvas is not a git repository, so it has no sha to write against', Canvas-Exit 2, and its next action says 'a read never writes one'. Re-running the read does not fix it; only create does. So sending the racy ENOENT to exit 1 makes the exit code depend on which side of a race the caller landed - the exact disease _nothing_at's docstring says must not happen ('a race is the only difference between them, and the refusal a caller gets should not depend on which side of it they landed'). It would also send that caller to 're-read and re-decide' against a store where re-reading provably raises the same thing. Separately: is_repository's ENOENT never reaches this helper at all, because FileNotFoundError is caught above it and answered False.</cell>
</row>
<row id="pjt3" v="1">
<cell id="ymcz" v="1">B. Leave every errno at exit 2 and put the reason in README.md section Exit codes: a canvas file that is not there is a true statement about the store, while a canvas repository that is not there is the tool's own environment missing, and exit 2 is the code for that.</cell>
<cell id="smym" v="1">Two sibling helpers, sitting 170 lines apart, with visibly different rules for the same errno, and only a paragraph of README holding the difference in place. Nothing in the code enforces it, so the next person doing this refactor removes the special case again - which is how it came to be left out of the parent change in the first place. It also leaves the refusal saying 'what that repository holds is still unknown' at exit 2 in the one case where the errno said plainly that it holds nothing, because it is not there.</cell>
</row>
<row id="nyah" v="1">
<cell id="fbym" v="1">C. Split by call site: return exit 1 where the caller can act on the absence (is_repository) and exit 2 where it cannot (head_sha, the --base resolution, the ancestry check), by giving _cannot_read_repository a parameter that says which.</cell>
<cell id="rt82" v="1">This is classification by the guard the failure landed in, which is exactly the rule the parent change was made to remove. The same errno on the same directory would come back as two different exit codes depending on which command the caller happened to run, and a caller cannot see which guard it is inside. It also puts a sixth parameter on a helper with five call sites, and every one of them has to get it right for the rule to hold.</cell>
</row>
</table>
<text id="nf98" v="1">Where Case 1's code now stands, on branch errno-on-repository-refusals. _cannot_read_repository branches on errno.ENOENT and returns a new helper, _no_repository_at, which gives _not_a_repository's claim and _not_a_repository's repair in _not_a_repository's words - and at _not_a_repository's exit 2. So the option taken in code is B: a repository that vanished is a 2 where a canvas file that vanished is a 1, and README.md section Exit codes now says why in its own words. What the errno changed is what the tool says, not the code it exits with. EACCES is untouched and still says it cannot tell, because there the look really did fail. This node records what the code does; it does not close the question above it, which is still open and still carries all three options.</text>
</section>
<section id="y9hx" v="1" title="Open question 2 - may a Canvas-Next: line name a command that exits non-zero at all?">
<question id="mqxd" v="1">May a Canvas-Next: name a command that exits non-zero at all? _OS_NEXT_ACTION[errno.ENOENT] says `ls -ld <path>` says which, and on a path that is genuinely gone that ls exits 1. The repair in the same template - bin/canvas create ... - succeeds. So this is not a broken repair; it is whether a next action may ever be a diagnostic rather than a repair.</question>
<table id="ehxj" v="1">
<row id="rysw" v="1">
<cell id="vp52" v="1">Option</cell>
<cell id="be5v" v="1">What it costs</cell>
</row>
<row id="vqpn" v="1">
<cell id="zksk" v="1">A. No. Every command a Canvas-Next: names must exit 0 when run against the state that produced the refusal. The `ls -ld` comes out of _OS_NEXT_ACTION[errno.ENOENT], and assertRepairsRun drops its chmod-only exemption and runs every command every template names.</cell>
<cell id="qdvs" v="1">A refusal can then only ever tell you to repair, never to look. The `ls -ld` on a missing path is not noise: its exit 1 and its 'No such file or directory' are the answer to which component of the path is gone, which is the thing a caller facing an ENOENT most wants to know and the thing bin/canvas cannot tell it. Dropping it means either finding a zero-exit way to ask the same question or accepting that the tool stops helping at the point the caller most needs it to.</cell>
</row>
<row id="yh66" v="1">
<cell id="vgke" v="1">B. Yes, provided README.md section What a refusal prints says so and says how a caller tells the diagnostic from the repair - and provided the format carries that distinction somewhere a machine can read it, rather than leaving it to be inferred from the verb.</cell>
<cell id="lp37" v="1">Canvas-Next: is one line of prose with no marker on it, so telling the two apart means inventing one - a second trailer, a prefix, or a structure the line does not currently have - and every existing template has to be classified against it. Short of that, assertRepairsRun keeps a hand-maintained list of which commands it is allowed to run, which is what the chmod-only exemption already is: the thing condition (3) was written to remove stays, wearing a justification.</cell>
</row>
</table>
<text id="echr" v="2">For whoever takes Case 2, corrected - my first version of this node had the count wrong. Two things. (i) The reproduce command in the todo does not print what it says it does: `python3 bin/canvas read no-such-ledger 2>&1 | grep 'Canvas-Next:'` prints _nothing_at's next action, "create it with bin/canvas create no-such-ledger ...", and no ls at all, because that path never reaches refusal.os_next_action. (ii) _OS_NEXT_ACTION[errno.ENOENT] is reachable from far fewer places than grepping for os_next_action suggests. store.py has six calls to it, but four of them sit under an `except OSError` that a separate `except FileNotFoundError` above has already taken ENOENT away from - _no_canvas, the OPENCLAW_WORKSPACE stat, _write_and_commit's pre-write stat, and now _cannot_read_repository. Checked empirically, not by reading: spying on refusal.os_next_action and handing each helper a FileNotFoundError, exactly one errno 2 got through, from _cannot_write. So before Case 1's change the template had two reachable sites in store.py and now it has one, and that one is _cannot_write - which says in its own docstring that it is exit 2 for every errno, ENOENT included. Its Canvas-Next is the `ls -ld <state/canvas>` one. Case 2 is still live and still testable, including directly at the helper, the way test_an_unclassified_errno_still_refuses_in_the_shape already does.</text>
</section>
</canvas>
python3 bin/canvas read bc-10329619223-errno-decides-the-repository-refusals
exit: 0
Canvas-Base: e950b24a9d809d1be42a551c26c37b58fdf5380c
<?xml version="1.0" encoding="UTF-8"?>
<canvas ledger="bc-10329619223-errno-decides-the-repository-refusals" schema="1">
<text id="bpx2" v="1">The parent change made every refusal's exit code, its repair and whatever it claims about the store derive from the errno the operating system actually returned, rather than from the guard the failure happened to land in - but one refusal helper and one next-action template were left outside that rule. canvas/store.py:582 _cannot_read_repository returns ToolProblem, exit 2, for every errno including ENOENT, where its sibling _cannot_read now returns exit 1 for ENOENT. canvas/refusal.py _OS_NEXT_ACTION[errno.ENOENT] says `ls -ld <path>` says which, and on a path that is genuinely gone that ls exits 1.</text>
<text id="bcr2" v="1">Every refusal helper in canvas/store.py that is handed an OSError chooses its exit code from the errno, _cannot_read_repository included - or README.md section Exit codes states, in its own words, why a repository that vanished is 2 where a canvas file that vanished is 1. A rule is settled and written down for whether a Canvas-Next: may name a command that exits non-zero. tests/test_store.py assertRepairsRun enforces whichever rule that settled. python3 -m unittest discover -s tests -t . passes from a clean tree, and the new behaviour fails against the code as it stands before the change - demonstrated, not asserted.</text>
<text id="fdzu" v="1">Branch base, and it is not main. Everything this todo cites exists only on origin/errors/actionable-refusal-surface, the branch of the still-open PR #8 for the parent todo 10326884685. On main there is no canvas/refusal.py at all, and canvas/store.py contains neither _cannot_read_repository nor _cannot_read - checked by git ls-tree and git show, both counts zero. So errno-on-repository-refusals is cut from origin/errors/actionable-refusal-surface at cd8d90e, and any half of this work branched from main names files that are not there. The suite on that branch is 263 tests, not main's 189.</text>
<section id="hp9p" v="1" title="Open question 1 - is a repository that vanished a 2 where a canvas file that vanished is a 1?">
<question id="t8zw" v="1">Should _cannot_read_repository return exit 1 for ENOENT, the way its sibling _cannot_read now does, or is a repository that vanished genuinely a different kind of failure from a canvas file that vanished, and so still a 2?</question>
<text id="bv2j" v="1">Observed, before anything was changed. Both routes the todo names were run. EACCES (chmod 000 on .git) gives exit 2 and that is right. The vanished-repository route - .git removed between is_repository's os.stat and head_sha's rev-parse, simulated the way the parent todo's test does - gives exit 2 with 'cannot tell whether there are any commits in <dir>: looking at it was refused: [Errno 2] No such file or directory', an aftermath of 'what that repository holds is still unknown', a Canvas-About of 'errno 2 ENOENT', and a Canvas-Next whose repair is 'bin/canvas create <ledger-id> ...' - immediately under a Canvas-Exit that reads 'do not touch the canvas'. The exit code is arguable. Those last two lines are not: on ENOENT the tool can tell, it does know what the repository holds (nothing, because there is none), and a refusal that names a bin/canvas command as the repair cannot in the same breath say do not touch the canvas.</text>
<table id="uz6x" v="1">
<row id="s437" v="1">
<cell id="sm4b" v="1">Option</cell>
<cell id="zyrd" v="1">What it costs</cell>
</row>
<row id="fu7f" v="1">
<cell id="mkyr" v="1">A. Classify by errno, exactly as _cannot_read does: ENOENT returns the exit-1 refusal, every other errno stays a ToolProblem at exit 2.</cell>
<cell id="lgvs" v="2">The five call sites are not alike, and worse: the same fact already has an exit code. _not_a_repository (canvas/store.py:352) is what fires when the check itself finds no .git, and it is exit 2 - reproduced: 'state/canvas is not a git repository, so it has no sha to write against', Canvas-Exit 2, and its next action says 'a read never writes one'. Re-running the read does not fix it; only create does. So sending the racy ENOENT to exit 1 makes the exit code depend on which side of a race the caller landed - the exact disease _nothing_at's docstring says must not happen ('a race is the only difference between them, and the refusal a caller gets should not depend on which side of it they landed'). It would also send that caller to 're-read and re-decide' against a store where re-reading provably raises the same thing. Separately: is_repository's ENOENT never reaches this helper at all, because FileNotFoundError is caught above it and answered False.</cell>
</row>
<row id="pjt3" v="1">
<cell id="ymcz" v="1">B. Leave every errno at exit 2 and put the reason in README.md section Exit codes: a canvas file that is not there is a true statement about the store, while a canvas repository that is not there is the tool's own environment missing, and exit 2 is the code for that.</cell>
<cell id="smym" v="1">Two sibling helpers, sitting 170 lines apart, with visibly different rules for the same errno, and only a paragraph of README holding the difference in place. Nothing in the code enforces it, so the next person doing this refactor removes the special case again - which is how it came to be left out of the parent change in the first place. It also leaves the refusal saying 'what that repository holds is still unknown' at exit 2 in the one case where the errno said plainly that it holds nothing, because it is not there.</cell>
</row>
<row id="nyah" v="1">
<cell id="fbym" v="1">C. Split by call site: return exit 1 where the caller can act on the absence (is_repository) and exit 2 where it cannot (head_sha, the --base resolution, the ancestry check), by giving _cannot_read_repository a parameter that says which.</cell>
<cell id="rt82" v="1">This is classification by the guard the failure landed in, which is exactly the rule the parent change was made to remove. The same errno on the same directory would come back as two different exit codes depending on which command the caller happened to run, and a caller cannot see which guard it is inside. It also puts a sixth parameter on a helper with five call sites, and every one of them has to get it right for the rule to hold.</cell>
</row>
</table>
<text id="nf98" v="1">Where Case 1's code now stands, on branch errno-on-repository-refusals. _cannot_read_repository branches on errno.ENOENT and returns a new helper, _no_repository_at, which gives _not_a_repository's claim and _not_a_repository's repair in _not_a_repository's words - and at _not_a_repository's exit 2. So the option taken in code is B: a repository that vanished is a 2 where a canvas file that vanished is a 1, and README.md section Exit codes now says why in its own words. What the errno changed is what the tool says, not the code it exits with. EACCES is untouched and still says it cannot tell, because there the look really did fail. This node records what the code does; it does not close the question above it, which is still open and still carries all three options.</text>
</section>
<section id="y9hx" v="1" title="Open question 2 - may a Canvas-Next: line name a command that exits non-zero at all?">
<question id="mqxd" v="1">May a Canvas-Next: name a command that exits non-zero at all? _OS_NEXT_ACTION[errno.ENOENT] says `ls -ld <path>` says which, and on a path that is genuinely gone that ls exits 1. The repair in the same template - bin/canvas create ... - succeeds. So this is not a broken repair; it is whether a next action may ever be a diagnostic rather than a repair.</question>
<table id="ehxj" v="1">
<row id="rysw" v="1">
<cell id="vp52" v="1">Option</cell>
<cell id="be5v" v="1">What it costs</cell>
</row>
<row id="vqpn" v="1">
<cell id="zksk" v="1">A. No. Every command a Canvas-Next: names must exit 0 when run against the state that produced the refusal. The `ls -ld` comes out of _OS_NEXT_ACTION[errno.ENOENT], and assertRepairsRun drops its chmod-only exemption and runs every command every template names.</cell>
<cell id="qdvs" v="1">A refusal can then only ever tell you to repair, never to look. The `ls -ld` on a missing path is not noise: its exit 1 and its 'No such file or directory' are the answer to which component of the path is gone, which is the thing a caller facing an ENOENT most wants to know and the thing bin/canvas cannot tell it. Dropping it means either finding a zero-exit way to ask the same question or accepting that the tool stops helping at the point the caller most needs it to.</cell>
</row>
<row id="yh66" v="1">
<cell id="vgke" v="1">B. Yes, provided README.md section What a refusal prints says so and says how a caller tells the diagnostic from the repair - and provided the format carries that distinction somewhere a machine can read it, rather than leaving it to be inferred from the verb.</cell>
<cell id="lp37" v="1">Canvas-Next: is one line of prose with no marker on it, so telling the two apart means inventing one - a second trailer, a prefix, or a structure the line does not currently have - and every existing template has to be classified against it. Short of that, assertRepairsRun keeps a hand-maintained list of which commands it is allowed to run, which is what the chmod-only exemption already is: the thing condition (3) was written to remove stays, wearing a justification.</cell>
</row>
</table>
<text id="echr" v="2">For whoever takes Case 2, corrected - my first version of this node had the count wrong. Two things. (i) The reproduce command in the todo does not print what it says it does: `python3 bin/canvas read no-such-ledger 2>&1 | grep 'Canvas-Next:'` prints _nothing_at's next action, "create it with bin/canvas create no-such-ledger ...", and no ls at all, because that path never reaches refusal.os_next_action. (ii) _OS_NEXT_ACTION[errno.ENOENT] is reachable from far fewer places than grepping for os_next_action suggests. store.py has six calls to it, but four of them sit under an `except OSError` that a separate `except FileNotFoundError` above has already taken ENOENT away from - _no_canvas, the OPENCLAW_WORKSPACE stat, _write_and_commit's pre-write stat, and now _cannot_read_repository. Checked empirically, not by reading: spying on refusal.os_next_action and handing each helper a FileNotFoundError, exactly one errno 2 got through, from _cannot_write. So before Case 1's change the template had two reachable sites in store.py and now it has one, and that one is _cannot_write - which says in its own docstring that it is exit 2 for every errno, ENOENT included. Its Canvas-Next is the `ls -ld <state/canvas>` one. Case 2 is still live and still testable, including directly at the helper, the way test_an_unclassified_errno_still_refuses_in_the_shape already does.</text>
</section>
</canvas>
python3 bin/canvas read no-such-ledger
exit: 1
canvas: no canvas for ledger id no-such-ledger: nothing at /Users/lfigea/.openclaw/runs/bc-10326884731-deliver-the-first-priority-canvas-todo-d/canvas-store/state/canvas/no-such-ledger.xml
Canvas-About: ledger id no-such-ledger
Canvas-About: canvas /Users/lfigea/.openclaw/runs/bc-10326884731-deliver-the-first-priority-canvas-todo-d/canvas-store/state/canvas/no-such-ledger.xml
Canvas-Next: create it with `bin/canvas create no-such-ledger --problem "<the problem>" --expected-value "<the expected value>"`, or re-run with the ledger id whose canvas you meant
Canvas-Exit: 1 — the request is wrong against the store as it stands; re-read and re-decide
OPENCLAW_WORKSPACE=/var/folders/sg/zqybmkjd4pjf3crgm2r9g2qc0000gn/T/tmp.9kGH7zLnG5/ws python3 bin/canvas read rec
exit: 1
canvas: no canvas for ledger id rec: nothing at /var/folders/sg/zqybmkjd4pjf3crgm2r9g2qc0000gn/T/tmp.9kGH7zLnG5/ws/state/canvas/rec.xml
Canvas-About: ledger id rec
Canvas-About: canvas /var/folders/sg/zqybmkjd4pjf3crgm2r9g2qc0000gn/T/tmp.9kGH7zLnG5/ws/state/canvas/rec.xml
Canvas-Next: create it with `bin/canvas create rec --problem "<the problem>" --expected-value "<the expected value>"`, or re-run with the ledger id whose canvas you meant
Canvas-Exit: 1 — the request is wrong against the store as it stands; re-read and re-decide
OPENCLAW_WORKSPACE=/var/folders/sg/zqybmkjd4pjf3crgm2r9g2qc0000gn/T/tmp.9kGH7zLnG5/ws python3 bin/canvas create rec --problem P --expected-value V
exit: 0
Canvas-Base: 24f3d1c1bfc540c9c540c5608454368a8cd62937
Canvas-File: /var/folders/sg/zqybmkjd4pjf3crgm2r9g2qc0000gn/T/tmp.9kGH7zLnG5/ws/state/canvas/rec.xml
OPENCLAW_WORKSPACE=/var/folders/sg/zqybmkjd4pjf3crgm2r9g2qc0000gn/T/tmp.9kGH7zLnG5/ws python3 bin/canvas read rec
exit: 0
Canvas-Base: 24f3d1c1bfc540c9c540c5608454368a8cd62937
<?xml version="1.0" encoding="UTF-8"?>
<canvas ledger="rec" schema="1">
<text id="ytwt" v="1">P</text>
<text id="n3tn" v="1">V</text>
</canvas>
OPENCLAW_WORKSPACE=<a mktemp -d workspace> python3 bin/canvas create '<ledger-id>' --problem '<the problem>' --expected-value '<the expected value>'
(the second writer, reproducing Case 2: the ENOENT template’s repair run verbatim, as the template prints it, rather than with its placeholders filled in)
exit: 2
canvas: not a usable ledger id: '<ledger-id>'; a ledger id is one or more of [A-Za-z0-9._-] and does not start with a dot
Canvas-About: ledger id '<ledger-id>'
Canvas-Next: re-run naming a ledger id of [A-Za-z0-9._-] that does not start with a dot; it becomes the name of a file in state/canvas, which is what stops one escaping that directory
Canvas-Exit: 2 — the tool or its environment is wrong; do not touch the canvas
python3 bin/canvas read bc-10329619223-errno-decides-the-repository-refusals
exit: 0
Canvas-Base: e950b24a9d809d1be42a551c26c37b58fdf5380c
<?xml version="1.0" encoding="UTF-8"?>
<canvas ledger="bc-10329619223-errno-decides-the-repository-refusals" schema="1">
<text id="bpx2" v="1">The parent change made every refusal's exit code, its repair and whatever it claims about the store derive from the errno the operating system actually returned, rather than from the guard the failure happened to land in - but one refusal helper and one next-action template were left outside that rule. canvas/store.py:582 _cannot_read_repository returns ToolProblem, exit 2, for every errno including ENOENT, where its sibling _cannot_read now returns exit 1 for ENOENT. canvas/refusal.py _OS_NEXT_ACTION[errno.ENOENT] says `ls -ld <path>` says which, and on a path that is genuinely gone that ls exits 1.</text>
<text id="bcr2" v="1">Every refusal helper in canvas/store.py that is handed an OSError chooses its exit code from the errno, _cannot_read_repository included - or README.md section Exit codes states, in its own words, why a repository that vanished is 2 where a canvas file that vanished is 1. A rule is settled and written down for whether a Canvas-Next: may name a command that exits non-zero. tests/test_store.py assertRepairsRun enforces whichever rule that settled. python3 -m unittest discover -s tests -t . passes from a clean tree, and the new behaviour fails against the code as it stands before the change - demonstrated, not asserted.</text>
<text id="fdzu" v="1">Branch base, and it is not main. Everything this todo cites exists only on origin/errors/actionable-refusal-surface, the branch of the still-open PR #8 for the parent todo 10326884685. On main there is no canvas/refusal.py at all, and canvas/store.py contains neither _cannot_read_repository nor _cannot_read - checked by git ls-tree and git show, both counts zero. So errno-on-repository-refusals is cut from origin/errors/actionable-refusal-surface at cd8d90e, and any half of this work branched from main names files that are not there. The suite on that branch is 263 tests, not main's 189.</text>
<section id="hp9p" v="1" title="Open question 1 - is a repository that vanished a 2 where a canvas file that vanished is a 1?">
<question id="t8zw" v="1">Should _cannot_read_repository return exit 1 for ENOENT, the way its sibling _cannot_read now does, or is a repository that vanished genuinely a different kind of failure from a canvas file that vanished, and so still a 2?</question>
<text id="bv2j" v="1">Observed, before anything was changed. Both routes the todo names were run. EACCES (chmod 000 on .git) gives exit 2 and that is right. The vanished-repository route - .git removed between is_repository's os.stat and head_sha's rev-parse, simulated the way the parent todo's test does - gives exit 2 with 'cannot tell whether there are any commits in <dir>: looking at it was refused: [Errno 2] No such file or directory', an aftermath of 'what that repository holds is still unknown', a Canvas-About of 'errno 2 ENOENT', and a Canvas-Next whose repair is 'bin/canvas create <ledger-id> ...' - immediately under a Canvas-Exit that reads 'do not touch the canvas'. The exit code is arguable. Those last two lines are not: on ENOENT the tool can tell, it does know what the repository holds (nothing, because there is none), and a refusal that names a bin/canvas command as the repair cannot in the same breath say do not touch the canvas.</text>
<table id="uz6x" v="1">
<row id="s437" v="1">
<cell id="sm4b" v="1">Option</cell>
<cell id="zyrd" v="1">What it costs</cell>
</row>
<row id="fu7f" v="1">
<cell id="mkyr" v="1">A. Classify by errno, exactly as _cannot_read does: ENOENT returns the exit-1 refusal, every other errno stays a ToolProblem at exit 2.</cell>
<cell id="lgvs" v="2">The five call sites are not alike, and worse: the same fact already has an exit code. _not_a_repository (canvas/store.py:352) is what fires when the check itself finds no .git, and it is exit 2 - reproduced: 'state/canvas is not a git repository, so it has no sha to write against', Canvas-Exit 2, and its next action says 'a read never writes one'. Re-running the read does not fix it; only create does. So sending the racy ENOENT to exit 1 makes the exit code depend on which side of a race the caller landed - the exact disease _nothing_at's docstring says must not happen ('a race is the only difference between them, and the refusal a caller gets should not depend on which side of it they landed'). It would also send that caller to 're-read and re-decide' against a store where re-reading provably raises the same thing. Separately: is_repository's ENOENT never reaches this helper at all, because FileNotFoundError is caught above it and answered False.</cell>
</row>
<row id="pjt3" v="1">
<cell id="ymcz" v="1">B. Leave every errno at exit 2 and put the reason in README.md section Exit codes: a canvas file that is not there is a true statement about the store, while a canvas repository that is not there is the tool's own environment missing, and exit 2 is the code for that.</cell>
<cell id="smym" v="1">Two sibling helpers, sitting 170 lines apart, with visibly different rules for the same errno, and only a paragraph of README holding the difference in place. Nothing in the code enforces it, so the next person doing this refactor removes the special case again - which is how it came to be left out of the parent change in the first place. It also leaves the refusal saying 'what that repository holds is still unknown' at exit 2 in the one case where the errno said plainly that it holds nothing, because it is not there.</cell>
</row>
<row id="nyah" v="1">
<cell id="fbym" v="1">C. Split by call site: return exit 1 where the caller can act on the absence (is_repository) and exit 2 where it cannot (head_sha, the --base resolution, the ancestry check), by giving _cannot_read_repository a parameter that says which.</cell>
<cell id="rt82" v="1">This is classification by the guard the failure landed in, which is exactly the rule the parent change was made to remove. The same errno on the same directory would come back as two different exit codes depending on which command the caller happened to run, and a caller cannot see which guard it is inside. It also puts a sixth parameter on a helper with five call sites, and every one of them has to get it right for the rule to hold.</cell>
</row>
</table>
<text id="nf98" v="1">Where Case 1's code now stands, on branch errno-on-repository-refusals. _cannot_read_repository branches on errno.ENOENT and returns a new helper, _no_repository_at, which gives _not_a_repository's claim and _not_a_repository's repair in _not_a_repository's words - and at _not_a_repository's exit 2. So the option taken in code is B: a repository that vanished is a 2 where a canvas file that vanished is a 1, and README.md section Exit codes now says why in its own words. What the errno changed is what the tool says, not the code it exits with. EACCES is untouched and still says it cannot tell, because there the look really did fail. This node records what the code does; it does not close the question above it, which is still open and still carries all three options.</text>
</section>
<section id="y9hx" v="1" title="Open question 2 - may a Canvas-Next: line name a command that exits non-zero at all?">
<question id="mqxd" v="1">May a Canvas-Next: name a command that exits non-zero at all? _OS_NEXT_ACTION[errno.ENOENT] says `ls -ld <path>` says which, and on a path that is genuinely gone that ls exits 1. The repair in the same template - bin/canvas create ... - succeeds. So this is not a broken repair; it is whether a next action may ever be a diagnostic rather than a repair.</question>
<table id="ehxj" v="1">
<row id="rysw" v="1">
<cell id="vp52" v="1">Option</cell>
<cell id="be5v" v="1">What it costs</cell>
</row>
<row id="vqpn" v="1">
<cell id="zksk" v="1">A. No. Every command a Canvas-Next: names must exit 0 when run against the state that produced the refusal. The `ls -ld` comes out of _OS_NEXT_ACTION[errno.ENOENT], and assertRepairsRun drops its chmod-only exemption and runs every command every template names.</cell>
<cell id="qdvs" v="1">A refusal can then only ever tell you to repair, never to look. The `ls -ld` on a missing path is not noise: its exit 1 and its 'No such file or directory' are the answer to which component of the path is gone, which is the thing a caller facing an ENOENT most wants to know and the thing bin/canvas cannot tell it. Dropping it means either finding a zero-exit way to ask the same question or accepting that the tool stops helping at the point the caller most needs it to.</cell>
</row>
<row id="yh66" v="1">
<cell id="vgke" v="1">B. Yes, provided README.md section What a refusal prints says so and says how a caller tells the diagnostic from the repair - and provided the format carries that distinction somewhere a machine can read it, rather than leaving it to be inferred from the verb.</cell>
<cell id="lp37" v="1">Canvas-Next: is one line of prose with no marker on it, so telling the two apart means inventing one - a second trailer, a prefix, or a structure the line does not currently have - and every existing template has to be classified against it. Short of that, assertRepairsRun keeps a hand-maintained list of which commands it is allowed to run, which is what the chmod-only exemption already is: the thing condition (3) was written to remove stays, wearing a justification.</cell>
</row>
</table>
<text id="echr" v="2">For whoever takes Case 2, corrected - my first version of this node had the count wrong. Two things. (i) The reproduce command in the todo does not print what it says it does: `python3 bin/canvas read no-such-ledger 2>&1 | grep 'Canvas-Next:'` prints _nothing_at's next action, "create it with bin/canvas create no-such-ledger ...", and no ls at all, because that path never reaches refusal.os_next_action. (ii) _OS_NEXT_ACTION[errno.ENOENT] is reachable from far fewer places than grepping for os_next_action suggests. store.py has six calls to it, but four of them sit under an `except OSError` that a separate `except FileNotFoundError` above has already taken ENOENT away from - _no_canvas, the OPENCLAW_WORKSPACE stat, _write_and_commit's pre-write stat, and now _cannot_read_repository. Checked empirically, not by reading: spying on refusal.os_next_action and handing each helper a FileNotFoundError, exactly one errno 2 got through, from _cannot_write. So before Case 1's change the template had two reachable sites in store.py and now it has one, and that one is _cannot_write - which says in its own docstring that it is exit 2 for every errno, ENOENT included. Its Canvas-Next is the `ls -ld <state/canvas>` one. Case 2 is still live and still testable, including directly at the helper, the way test_an_unclassified_errno_still_refuses_in_the_shape already does.</text>
</section>
</canvas>
python3 bin/canvas replace bc-10329619223-errno-decides-the-repository-refusals mqxd --type text --text SETTLED, by the second writer, 2026-09-22: yes - a Canvas-Next: may name a command that exits non-zero, and one word says which one it may not. A command written after the word run is the repair: it is printed ready to run against real paths, running it is what makes the refused command work, and it exits 0. Everything else a next action names is either a diagnostic - ls -ld, ls -l, df -h, ulimit -n, there to show the state that produced the refusal - whose exit status is the answer and not a failure; or a form, a command with a <placeholder> in it that nobody runs as printed. So the rule the tool holds itself to is not 'every command a next action names succeeds' but 'every command a next action tells you to run succeeds'. The reason is not taste, it is what happened when I ran it. Option A - every command must exit 0 - is not implementable without gutting the surface: rendering all fifteen templates against a path that is genuinely gone and running every backticked command in each shows that four of them are not commands at all (ulimit -n is a shell builtin, | cat | head -1 and | head -1 are pipe fragments, chown is named bare with no operands) and that the ENOENT template's own repair exits 2 run verbatim, because it prints <ledger-id> where a ledger id goes. The remaining diagnostics exit 1 on precisely the condition their template exists for, because every way of looking at a path that is gone reports that it is gone by exiting non-zero. A would therefore either forbid a refusal about a missing path from telling a caller to look at it - the one thing a caller facing ENOENT most needs - or leave assertRepairsRun holding the hand-maintained allowlist that condition (3) was written to remove. B costs one marker, and the marker is syntactic rather than a list of command names, so a template that adds a repair nobody anticipated is covered the moment it is written. --author claude-opus-5 | second-writer --why settling open question 2: a Canvas-Next may name a command that exits non-zero, but only a diagnostic or a form may, and the word 'run' marks the one that may not. Decided on evidence rather than on taste - running every command all fifteen _OS_NEXT_ACTION templates name showed four of them are not commands at all and that the ENOENT template's own repair exits 2 verbatim, so 'every command must exit 0' cannot be held without deleting the diagnostics that make an ENOENT refusal useful. The question node becomes the answer because the tool has no way to mark a question answered while leaving it standing; the question itself is still in this node's history. --base e950b24a9d809d1be42a551c26c37b58fdf5380c
exit: 0
Canvas-Node: mqxd
Canvas-Base: f7be9ea2a5f2207b66d5eb949d64967c0a27849d
python3 bin/canvas replace bc-10329619223-errno-decides-the-repository-refusals vgke --text CHOSEN. B. Yes, provided README.md section What a refusal prints says so and says how a caller tells the diagnostic from the repair - and provided the format carries that distinction somewhere a machine can read it, rather than leaving it to be inferred from the verb. As implemented: the distinction is the word run immediately in front of the command, README.md states it, and tests/test_store.py's assertRepairsRun reads it. --author claude-opus-5 | second-writer --why marking on the options table itself which option the decision above took, because a reader who scrolls to the table should not have to reconstruct it from the prose. The tool has no way to mark a row chosen - there is no status on a node - so the word goes in the cell's own text, and the cell now also records how the option's proviso was actually met rather than leaving it as a condition nobody has checked. --base f7be9ea2a5f2207b66d5eb949d64967c0a27849d
exit: 0
Canvas-Node: vgke
Canvas-Base: 90907b5cb80135bd584a06711055c00f0ed2c519
python3 bin/canvas replace bc-10329619223-errno-decides-the-repository-refusals lp37 --text What it cost, now that it has been paid rather than estimated. The estimate here was that telling the two apart means inventing a marker - a second trailer, a prefix, or a structure the line does not have - and that short of that assertRepairsRun keeps a hand-maintained list of commands it is allowed to run, which is the chmod-only exemption wearing a justification. Half right. A marker did have to be invented, but it cost one word in one template: _OS_NEXT_ACTION[errno.EACCES] is the only template in the whole table that names a command that is both runnable and a repair, so 'every existing template has to be classified against it' turned out to be one edit and not fifteen. And the marker is syntactic, not a list: assertRepairsRun runs whatever a next action marks with run, so a repair nobody anticipated is covered the moment somebody writes it. What is genuinely left over is that the marker is a word in prose rather than a trailer, so it is one careless sentence away from being dropped. The only thing holding it is the assertion in the other direction - every chmod a next action names must be marked - and that holds for chmod alone, because chmod is the one command in the surface that exists solely to make the refused command work. A second repair command that nobody marks would pass. --author claude-opus-5 | second-writer --why correcting this cost cell against what the option actually cost to implement, the way the first writer corrected lgvs after running the other route. The estimate said every existing template would have to be classified and that the exemption would survive as an allowlist; in fact one template names a runnable repair and the marker is syntactic, so neither happened. But the estimate was right that the format carries no structure for this, and the residue it was pointing at is real and is now named precisely: the marker is prose and only the chmod converse check holds it. --base 90907b5cb80135bd584a06711055c00f0ed2c519
exit: 0
Canvas-Node: lp37
Canvas-Base: f0e23e095c543e502a0f54f06156d15d9532f0af
python3 bin/canvas insert bc-10329619223-errno-decides-the-repository-refusals --into y9hx --type text --text What running it showed, 2026-09-22, and two corrections to the todo's own text. I rendered every _OS_NEXT_ACTION template against a path that is genuinely gone and ran every backticked command each one names. Exit codes, verbatim: ls -ld ` 1; `ls -l ` 1; `df -h ` 1; `ulimit -n` 0; `chown` (named bare, no operands) 1; `bin/canvas create --problem "" --expected-value ""` 2, refused as 'not a usable ledger id'; `| cat | head -1` could not be run at all - [Errno 2] No such file or directory: '|'. Correction one: the todo says the repair in the ENOENT template 'succeeds and the parent todo's test runs it verbatim'. It does not succeed run verbatim, and the test does not run it. tests/test_store.py:4304 takes `bin/canvas create a-ledger-row` out of a different refusal - _nothing_at's, which fills the ledger id in - and then runs create with --problem P --expected-value V, substituting for the placeholders by hand. Correction two: the ENOENT template says `ls -ld ` 'says which' directory on the way is missing. It does not. Checked both ways on the same machine: ls -ld prints one line and exits 1 whether the leaf is missing or a directory three levels up is, and the line names the path it was given either way. The diagnostic is still worth keeping - it distinguishes gone from unreadable, which is what a caller most needs - but it does not answer the question the template claims for it. --author claude-opus-5 | second-writer --why the evidence the decision above stands on, written down as exit codes rather than as a claim, because the decision turns entirely on the observation that four of the things these templates name are not commands at all. Also the place two errors in the todo's own description get recorded: its Case 2 reproduce steps assert a repair runs verbatim that exits 2, and the template asserts a diagnostic answers a question it does not answer. A later reader checking my reasoning needs both, and neither is visible from the code. --base f0e23e095c543e502a0f54f06156d15d9532f0af`
exit: 0
Canvas-Node: l32v
Canvas-Base: 61f5d74e2bf3fda65e05c7e4e92a4e48254d4ff5
python3 bin/canvas insert bc-10329619223-errno-decides-the-repository-refusals --into y9hx --type text --text Where Case 2's code now stands, on branch errno-on-repository-refusals. canvas/refusal.py: the module docstring and the comment block over _OS_NEXT_ACTION state the rule and name the three kinds of thing a next action may hold - repair, diagnostic, form. _OS_NEXT_ACTION[errno.EACCES] is the only template in the table that names a command that is both runnable and a repair, and it now reads 'the repair is usually to run chmod …' where it read 'chmod … is usually the repair'. No other template changed, because no other template names a runnable repair. README.md section What a refusal prints carries the rule in full, with the ls -ld exit 1 example and the bin/canvas create <ledger-id> form, and says which of the three a caller is looking at. tests/test_store.py assertRepairsRun no longer carries the chmod-only exemption: it runs every command a Canvas-Next: marks with run, whatever that command is, asserts it exits 0 and that it carries no <placeholder>, and asserts in the other direction that every chmod a next action names is marked as a repair - which is what stops the rule being satisfied by deleting the word. Demonstrated both ways rather than asserted. Against refusal.py exactly as it stood, the new assertion fails: 'named chmod u+rx …/a-ledger-row.xml without telling the caller to run it', 12 tests, FAILED (failures=1). With the change the same class is 12 tests OK and python3 -m unittest discover -s tests -t . is 263 tests OK. I also checked the assertion is not vacuous by pointing the marked repair at an invalid mode: it fails with 'chmod nosuchmode … is named as the repair and exited 1', so the command really is executed. --author claude-opus-5 | second-writer --why so that the next reader can tell what the decision above cost in code without reading the diff, and so that the two demonstrations condition (4) asks for - the new behaviour failing before and passing after - are recorded where the decision is rather than only in a commit message. The vacuity check is in here on purpose: an assertion that runs no command passes for the wrong reason, and the canvas should say that somebody looked. --base 61f5d74e2bf3fda65e05c7e4e92a4e48254d4ff5
exit: 0
Canvas-Node: ev4w
Canvas-Base: 764554a3656a56f589a00fbe09693cc25a88365e
python3 bin/canvas insert bc-10329619223-errno-decides-the-repository-refusals --into y9hx --type text --text What the decision leaves open, named here so it is not mistaken for settled. (i) After this change _OS_NEXT_ACTION[errno.ENOENT] names no repair at all - a diagnostic and a form, and nothing marked run. That is allowed by the rule as settled, which says every command a next action tells you to run succeeds, not that every next action has a runnable repair to name. Whether a refusal ought to be required to name one is a different question and nothing in the repository asks it yet. (ii) The marker is a word in prose, not a trailer of its own, so it survives only as long as nobody rewrites the sentence around it. The single thing holding it is the converse assertion - every chmod a next action names must be marked - and that generalises to exactly one command, because chmod is the only one in the surface whose whole purpose is to make the refused command work. A second repair command that nobody marks would pass the suite. A Canvas-Repair: trailer beside Canvas-Next: would close that, at the cost of a sixth line in a block README describes as five. (iii) Both cases of todo 10329619223 are now answered on this branch, and the branch still does not descend from main - see node fdzu. A PR from it targets errors/actionable-refusal-surface, or waits for PR #8. --author claude-opus-5 | second-writer --why a decision that does not say what it left open reads later as if it covered everything, and the two loose ends here are both things a reviewer would otherwise have to find for themselves: the ENOENT template now names no repair, and the marker is prose held up by a check that generalises to one command. Naming the trailer that would close it, and what it would cost, so that whoever picks it up is deciding rather than rediscovering. --base 764554a3656a56f589a00fbe09693cc25a88365e
exit: 0
Canvas-Node: g9ah
Canvas-Base: 92361689a3342864ccc2a98c43689cfca30eea9a
python3 bin/canvas replace bc-10329619223-errno-decides-the-repository-refusals mqxd --text a probe: what does the tool say to a writer still holding the base the first writer handed over? --author claude-opus-5 | second-writer --why probing the staleness check deliberately: writing the question node again against e950b24a, the base the first writer's handoff note still holds, to see what the tool tells a second writer who arrives with it --base e950b24a9d809d1be42a551c26c37b58fdf5380c
exit: 1
canvas: refusing to write mqxd in the canvas for bc-10329619223-errno-decides-the-repository-refusals: it moved in 1 commit(s) between --base e950b24a9d809d1be42a551c26c37b58fdf5380c and 92361689a3342864ccc2a98c43689cfca30eea9a, so this edit was decided against text that is no longer there. Nothing was applied and nothing was merged. Its diff since e950b24a9d809d1be42a551c26c37b58fdf5380c follows
Canvas-Commit: f7be9ea2a5f2207b66d5eb949d64967c0a27849d
replace mqxd: settling open question 2: a Canvas-Next may name a command that exits non-zero, but only a diagnostic or a form may, and the word 'run' marks the one that may not. Decided on evidence rather than on taste - running every command all fifteen _OS_NEXT_ACTION templates name showed four of them are not commands at all and that the ENOENT template's own repair exits 2 verbatim, so 'every command must exit 0' cannot be held without deleting the diagnostics that make an ENOENT refusal useful. The question node becomes the answer because the tool has no way to mark a question answered while leaving it standing; the question itself is still in this node's history.
diff --git a/bc-10329619223-errno-decides-the-repository-refusals.xml b/bc-10329619223-errno-decides-the-repository-refusals.xml
index 4c0c5d5..72da4f8 100644
--- a/bc-10329619223-errno-decides-the-repository-refusals.xml
+++ b/bc-10329619223-errno-decides-the-repository-refusals.xml
@@ -27,7 +27,7 @@
<text id="nf98" v="1">Where Case 1's code now stands, on branch errno-on-repository-refusals. _cannot_read_repository branches on errno.ENOENT and returns a new helper, _no_repository_at, which gives _not_a_repository's claim and _not_a_repository's repair in _not_a_repository's words - and at _not_a_repository's exit 2. So the option taken in code is B: a repository that vanished is a 2 where a canvas file that vanished is a 1, and README.md section Exit codes now says why in its own words. What the errno changed is what the tool says, not the code it exits with. EACCES is untouched and still says it cannot tell, because there the look really did fail. This node records what the code does; it does not close the question above it, which is still open and still carries all three options.</text>
</section>
<section id="y9hx" v="1" title="Open question 2 - may a Canvas-Next: line name a command that exits non-zero at all?">
- <question id="mqxd" v="1">May a Canvas-Next: name a command that exits non-zero at all? _OS_NEXT_ACTION[errno.ENOENT] says `ls -ld <path>` says which, and on a path that is genuinely gone that ls exits 1. The repair in the same template - bin/canvas create ... - succeeds. So this is not a broken repair; it is whether a next action may ever be a diagnostic rather than a repair.</question>
+ <text id="mqxd" v="2">SETTLED, by the second writer, 2026-09-22: yes - a Canvas-Next: may name a command that exits non-zero, and one word says which one it may not. A command written after the word `run` is the repair: it is printed ready to run against real paths, running it is what makes the refused command work, and it exits 0. Everything else a next action names is either a diagnostic - `ls -ld`, `ls -l`, `df -h`, `ulimit -n`, there to show the state that produced the refusal - whose exit status is the answer and not a failure; or a form, a command with a <placeholder> in it that nobody runs as printed. So the rule the tool holds itself to is not 'every command a next action names succeeds' but 'every command a next action tells you to run succeeds'. The reason is not taste, it is what happened when I ran it. Option A - every command must exit 0 - is not implementable without gutting the surface: rendering all fifteen templates against a path that is genuinely gone and running every backticked command in each shows that four of them are not commands at all (`ulimit -n` is a shell builtin, `| cat | head -1` and `| head -1` are pipe fragments, `chown` is named bare with no operands) and that the ENOENT template's own repair exits 2 run verbatim, because it prints <ledger-id> where a ledger id goes. The remaining diagnostics exit 1 on precisely the condition their template exists for, because every way of looking at a path that is gone reports that it is gone by exiting non-zero. A would therefore either forbid a refusal about a missing path from telling a caller to look at it - the one thing a caller facing ENOENT most needs - or leave assertRepairsRun holding the hand-maintained allowlist that condition (3) was written to remove. B costs one marker, and the marker is syntactic rather than a list of command names, so a template that adds a repair nobody anticipated is covered the moment it is written.</text>
<table id="ehxj" v="1">
<row id="rysw" v="1">
<cell id="vp52" v="1">Option</cell>
Canvas-Node: mqxd
Canvas-About: ledger id bc-10329619223-errno-decides-the-repository-refusals
Canvas-About: canvas /Users/lfigea/.openclaw/runs/bc-10326884731-deliver-the-first-priority-canvas-todo-d/canvas-store/state/canvas/bc-10329619223-errno-decides-the-repository-refusals.xml
Canvas-About: option --base e950b24a9d809d1be42a551c26c37b58fdf5380c
Canvas-About: sha 92361689a3342864ccc2a98c43689cfca30eea9a, the head
Canvas-Next: read the canvas again with `bin/canvas read bc-10329619223-errno-decides-the-repository-refusals`, re-decide against the sha it prints, and re-run this edit with that --base
Canvas-Exit: 1 — the request is wrong against the store as it stands; re-read and re-decide
python3 bin/canvas insert bc-10329619223-errno-decides-the-repository-refusals --into y9hx --type text --text What the tool did about a second writer, recorded by the second writer. I arrived on this canvas holding e950b24a, the sha the first writer's handoff note names, and read it back before touching anything - it was still the head, so nothing had moved. After my own six edits I deliberately re-ran the edit to mqxd against e950b24a to see what the tool says to somebody who did not re-read. It took the hard branch: exit 1, 'refusing to write mqxd ... it moved in 1 commit(s) between --base e950b24a and 92361689, so this edit was decided against text that is no longer there. Nothing was applied and nothing was merged', then the intervening commit's subject, which is the whole --why of the edit that moved it, then git's own diff of the node from the old text to the new. Canvas-About: named the ledger id, the file, the --base I gave and the head; Canvas-Next: told me to read again, re-decide against the sha the read prints, and re-run with that --base. That is enough to act on without asking anybody: the reason the other writer changed it is in the output, so the re-decision can be made from the refusal itself rather than by reading the document again first. This node itself was inserted against the same stale e950b24a, which takes the soft branch instead - the write applies, and the same stdout that reports success carries Canvas-News and every intervening commit. What the tool does not carry either way is that somebody else is holding a base at all: read hands out a sha and says nothing about who wrote last or how old it is, so a second writer learns there was a first one from a Markdown file beside the canvas, not from the canvas. --author claude-opus-5 | second-writer --why the canvas is supposed to hold the shared understanding between the people and the agents on a task, and 'what happens when two of us write to it' is part of that understanding and was not in it. Recording what the staleness check actually did to me rather than what the README says it does, including the one thing it does not do: nothing in the tool told me another writer existed. Written against the first writer's base on purpose, so that the soft branch is demonstrated by the same edit that describes the hard one. --base e950b24a9d809d1be42a551c26c37b58fdf5380c
exit: 0
Canvas-Node: qrpa
Canvas-Base: 2d7ae95c09c28d81cde89d14a5bc2b8b1713b5e7
Canvas-News: 6 commit(s) between e950b24a9d809d1be42a551c26c37b58fdf5380c and 92361689a3342864ccc2a98c43689cfca30eea9a
replace mqxd: settling open question 2: a Canvas-Next may name a command that exits non-zero, but only a diagnostic or a form may, and the word 'run' marks the one that may not. Decided on evidence rather than on taste - running every command all fifteen _OS_NEXT_ACTION templates name showed four of them are not commands at all and that the ENOENT template's own repair exits 2 verbatim, so 'every command must exit 0' cannot be held without deleting the diagnostics that make an ENOENT refusal useful. The question node becomes the answer because the tool has no way to mark a question answered while leaving it standing; the question itself is still in this node's history.
replace vgke: marking on the options table itself which option the decision above took, because a reader who scrolls to the table should not have to reconstruct it from the prose. The tool has no way to mark a row chosen - there is no status on a node - so the word goes in the cell's own text, and the cell now also records how the option's proviso was actually met rather than leaving it as a condition nobody has checked.
replace lp37: correcting this cost cell against what the option actually cost to implement, the way the first writer corrected lgvs after running the other route. The estimate said every existing template would have to be classified and that the exemption would survive as an allowlist; in fact one template names a runnable repair and the marker is syntactic, so neither happened. But the estimate was right that the format carries no structure for this, and the residue it was pointing at is real and is now named precisely: the marker is prose and only the chmod converse check holds it.
insert l32v: the evidence the decision above stands on, written down as exit codes rather than as a claim, because the decision turns entirely on the observation that four of the things these templates name are not commands at all. Also the place two errors in the todo's own description get recorded: its Case 2 reproduce steps assert a repair runs verbatim that exits 2, and the template asserts a diagnostic answers a question it does not answer. A later reader checking my reasoning needs both, and neither is visible from the code.
insert ev4w: so that the next reader can tell what the decision above cost in code without reading the diff, and so that the two demonstrations condition (4) asks for - the new behaviour failing before and passing after - are recorded where the decision is rather than only in a commit message. The vacuity check is in here on purpose: an assertion that runs no command passes for the wrong reason, and the canvas should say that somebody looked.
insert g9ah: a decision that does not say what it left open reads later as if it covered everything, and the two loose ends here are both things a reviewer would otherwise have to find for themselves: the ENOENT template now names no repair, and the marker is prose held up by a check that generalises to one command. Naming the trailer that would close it, and what it would cost, so that whoever picks it up is deciding rather than rediscovering.
diff --git a/bc-10329619223-errno-decides-the-repository-refusals.xml b/bc-10329619223-errno-decides-the-repository-refusals.xml
index 4c0c5d5..5b69096 100644
--- a/bc-10329619223-errno-decides-the-repository-refusals.xml
+++ b/bc-10329619223-errno-decides-the-repository-refusals.xml
@@ -27,7 +27,7 @@
<text id="nf98" v="1">Where Case 1's code now stands, on branch errno-on-repository-refusals. _cannot_read_repository branches on errno.ENOENT and returns a new helper, _no_repository_at, which gives _not_a_repository's claim and _not_a_repository's repair in _not_a_repository's words - and at _not_a_repository's exit 2. So the option taken in code is B: a repository that vanished is a 2 where a canvas file that vanished is a 1, and README.md section Exit codes now says why in its own words. What the errno changed is what the tool says, not the code it exits with. EACCES is untouched and still says it cannot tell, because there the look really did fail. This node records what the code does; it does not close the question above it, which is still open and still carries all three options.</text>
</section>
<section id="y9hx" v="1" title="Open question 2 - may a Canvas-Next: line name a command that exits non-zero at all?">
- <question id="mqxd" v="1">May a Canvas-Next: name a command that exits non-zero at all? _OS_NEXT_ACTION[errno.ENOENT] says `ls -ld <path>` says which, and on a path that is genuinely gone that ls exits 1. The repair in the same template - bin/canvas create ... - succeeds. So this is not a broken repair; it is whether a next action may ever be a diagnostic rather than a repair.</question>
+ <text id="mqxd" v="2">SETTLED, by the second writer, 2026-09-22: yes - a Canvas-Next: may name a command that exits non-zero, and one word says which one it may not. A command written after the word `run` is the repair: it is printed ready to run against real paths, running it is what makes the refused command work, and it exits 0. Everything else a next action names is either a diagnostic - `ls -ld`, `ls -l`, `df -h`, `ulimit -n`, there to show the state that produced the refusal - whose exit status is the answer and not a failure; or a form, a command with a <placeholder> in it that nobody runs as printed. So the rule the tool holds itself to is not 'every command a next action names succeeds' but 'every command a next action tells you to run succeeds'. The reason is not taste, it is what happened when I ran it. Option A - every command must exit 0 - is not implementable without gutting the surface: rendering all fifteen templates against a path that is genuinely gone and running every backticked command in each shows that four of them are not commands at all (`ulimit -n` is a shell builtin, `| cat | head -1` and `| head -1` are pipe fragments, `chown` is named bare with no operands) and that the ENOENT template's own repair exits 2 run verbatim, because it prints <ledger-id> where a ledger id goes. The remaining diagnostics exit 1 on precisely the condition their template exists for, because every way of looking at a path that is gone reports that it is gone by exiting non-zero. A would therefore either forbid a refusal about a missing path from telling a caller to look at it - the one thing a caller facing ENOENT most needs - or leave assertRepairsRun holding the hand-maintained allowlist that condition (3) was written to remove. B costs one marker, and the marker is syntactic rather than a list of command names, so a template that adds a repair nobody anticipated is covered the moment it is written.</text>
<table id="ehxj" v="1">
<row id="rysw" v="1">
<cell id="vp52" v="1">Option</cell>
@@ -38,10 +38,13 @@
<cell id="qdvs" v="1">A refusal can then only ever tell you to repair, never to look. The `ls -ld` on a missing path is not noise: its exit 1 and its 'No such file or directory' are the answer to which component of the path is gone, which is the thing a caller facing an ENOENT most wants to know and the thing bin/canvas cannot tell it. Dropping it means either finding a zero-exit way to ask the same question or accepting that the tool stops helping at the point the caller most needs it to.</cell>
</row>
<row id="yh66" v="1">
- <cell id="vgke" v="1">B. Yes, provided README.md section What a refusal prints says so and says how a caller tells the diagnostic from the repair - and provided the format carries that distinction somewhere a machine can read it, rather than leaving it to be inferred from the verb.</cell>
- <cell id="lp37" v="1">Canvas-Next: is one line of prose with no marker on it, so telling the two apart means inventing one - a second trailer, a prefix, or a structure the line does not currently have - and every existing template has to be classified against it. Short of that, assertRepairsRun keeps a hand-maintained list of which commands it is allowed to run, which is what the chmod-only exemption already is: the thing condition (3) was written to remove stays, wearing a justification.</cell>
+ <cell id="vgke" v="2">CHOSEN. B. Yes, provided README.md section What a refusal prints says so and says how a caller tells the diagnostic from the repair - and provided the format carries that distinction somewhere a machine can read it, rather than leaving it to be inferred from the verb. As implemented: the distinction is the word `run` immediately in front of the command, README.md states it, and tests/test_store.py's assertRepairsRun reads it.</cell>
+ <cell id="lp37" v="2">What it cost, now that it has been paid rather than estimated. The estimate here was that telling the two apart means inventing a marker - a second trailer, a prefix, or a structure the line does not have - and that short of that assertRepairsRun keeps a hand-maintained list of commands it is allowed to run, which is the chmod-only exemption wearing a justification. Half right. A marker did have to be invented, but it cost one word in one template: _OS_NEXT_ACTION[errno.EACCES] is the only template in the whole table that names a command that is both runnable and a repair, so 'every existing template has to be classified against it' turned out to be one edit and not fifteen. And the marker is syntactic, not a list: assertRepairsRun runs whatever a next action marks with `run`, so a repair nobody anticipated is covered the moment somebody writes it. What is genuinely left over is that the marker is a word in prose rather than a trailer, so it is one careless sentence away from being dropped. The only thing holding it is the assertion in the other direction - every chmod a next action names must be marked - and that holds for chmod alone, because chmod is the one command in the surface that exists solely to make the refused command work. A second repair command that nobody marks would pass.</cell>
</row>
</table>
<text id="echr" v="2">For whoever takes Case 2, corrected - my first version of this node had the count wrong. Two things. (i) The reproduce command in the todo does not print what it says it does: `python3 bin/canvas read no-such-ledger 2>&1 | grep 'Canvas-Next:'` prints _nothing_at's next action, "create it with bin/canvas create no-such-ledger ...", and no ls at all, because that path never reaches refusal.os_next_action. (ii) _OS_NEXT_ACTION[errno.ENOENT] is reachable from far fewer places than grepping for os_next_action suggests. store.py has six calls to it, but four of them sit under an `except OSError` that a separate `except FileNotFoundError` above has already taken ENOENT away from - _no_canvas, the OPENCLAW_WORKSPACE stat, _write_and_commit's pre-write stat, and now _cannot_read_repository. Checked empirically, not by reading: spying on refusal.os_next_action and handing each helper a FileNotFoundError, exactly one errno 2 got through, from _cannot_write. So before Case 1's change the template had two reachable sites in store.py and now it has one, and that one is _cannot_write - which says in its own docstring that it is exit 2 for every errno, ENOENT included. Its Canvas-Next is the `ls -ld <state/canvas>` one. Case 2 is still live and still testable, including directly at the helper, the way test_an_unclassified_errno_still_refuses_in_the_shape already does.</text>
+ <text id="l32v" v="1">What running it showed, 2026-09-22, and two corrections to the todo's own text. I rendered every _OS_NEXT_ACTION template against a path that is genuinely gone and ran every backticked command each one names. Exit codes, verbatim: `ls -ld <gone>` 1; `ls -l <gone>` 1; `df -h <gone>` 1; `ulimit -n` 0; `chown` (named bare, no operands) 1; `bin/canvas create <ledger-id> --problem "<the problem>" --expected-value "<the expected value>"` 2, refused as 'not a usable ledger id'; `| cat | head -1` could not be run at all - [Errno 2] No such file or directory: '|'. Correction one: the todo says the repair in the ENOENT template 'succeeds and the parent todo's test runs it verbatim'. It does not succeed run verbatim, and the test does not run it. tests/test_store.py:4304 takes `bin/canvas create a-ledger-row` out of a different refusal - _nothing_at's, which fills the ledger id in - and then runs create with --problem P --expected-value V, substituting for the <the problem> placeholders by hand. Correction two: the ENOENT template says `ls -ld <path>` 'says which' directory on the way is missing. It does not. Checked both ways on the same machine: ls -ld prints one line and exits 1 whether the leaf is missing or a directory three levels up is, and the line names the path it was given either way. The diagnostic is still worth keeping - it distinguishes gone from unreadable, which is what a caller most needs - but it does not answer the question the template claims for it.</text>
+ <text id="ev4w" v="1">Where Case 2's code now stands, on branch errno-on-repository-refusals. canvas/refusal.py: the module docstring and the comment block over _OS_NEXT_ACTION state the rule and name the three kinds of thing a next action may hold - repair, diagnostic, form. _OS_NEXT_ACTION[errno.EACCES] is the only template in the table that names a command that is both runnable and a repair, and it now reads 'the repair is usually to run `chmod ...`' where it read '`chmod ...` is usually the repair'. No other template changed, because no other template names a runnable repair. README.md section What a refusal prints carries the rule in full, with the ls -ld exit 1 example and the bin/canvas create <ledger-id> form, and says which of the three a caller is looking at. tests/test_store.py assertRepairsRun no longer carries the chmod-only exemption: it runs every command a Canvas-Next: marks with `run`, whatever that command is, asserts it exits 0 and that it carries no <placeholder>, and asserts in the other direction that every chmod a next action names is marked as a repair - which is what stops the rule being satisfied by deleting the word. Demonstrated both ways rather than asserted. Against refusal.py exactly as it stood, the new assertion fails: 'named `chmod u+rx .../a-ledger-row.xml` without telling the caller to run it', 12 tests, FAILED (failures=1). With the change the same class is 12 tests OK and python3 -m unittest discover -s tests -t . is 263 tests OK. I also checked the assertion is not vacuous by pointing the marked repair at an invalid mode: it fails with '`chmod nosuchmode ...` is named as the repair and exited 1', so the command really is executed.</text>
+ <text id="g9ah" v="1">What the decision leaves open, named here so it is not mistaken for settled. (i) After this change _OS_NEXT_ACTION[errno.ENOENT] names no repair at all - a diagnostic and a form, and nothing marked `run`. That is allowed by the rule as settled, which says every command a next action tells you to run succeeds, not that every next action has a runnable repair to name. Whether a refusal ought to be required to name one is a different question and nothing in the repository asks it yet. (ii) The marker is a word in prose, not a trailer of its own, so it survives only as long as nobody rewrites the sentence around it. The single thing holding it is the converse assertion - every chmod a next action names must be marked - and that generalises to exactly one command, because chmod is the only one in the surface whose whole purpose is to make the refused command work. A second repair command that nobody marks would pass the suite. A Canvas-Repair: trailer beside Canvas-Next: would close that, at the cost of a sixth line in a block README describes as five. (iii) Both cases of todo 10329619223 are now answered on this branch, and the branch still does not descend from main - see node fdzu. A PR from it targets errors/actionable-refusal-surface, or waits for PR #8.</text>
</section>
</canvas>
python3 bin/canvas read bc-10329619223-errno-decides-the-repository-refusals
exit: 0
Canvas-Base: 2d7ae95c09c28d81cde89d14a5bc2b8b1713b5e7
<?xml version="1.0" encoding="UTF-8"?>
<canvas ledger="bc-10329619223-errno-decides-the-repository-refusals" schema="1">
<text id="bpx2" v="1">The parent change made every refusal's exit code, its repair and whatever it claims about the store derive from the errno the operating system actually returned, rather than from the guard the failure happened to land in - but one refusal helper and one next-action template were left outside that rule. canvas/store.py:582 _cannot_read_repository returns ToolProblem, exit 2, for every errno including ENOENT, where its sibling _cannot_read now returns exit 1 for ENOENT. canvas/refusal.py _OS_NEXT_ACTION[errno.ENOENT] says `ls -ld <path>` says which, and on a path that is genuinely gone that ls exits 1.</text>
<text id="bcr2" v="1">Every refusal helper in canvas/store.py that is handed an OSError chooses its exit code from the errno, _cannot_read_repository included - or README.md section Exit codes states, in its own words, why a repository that vanished is 2 where a canvas file that vanished is 1. A rule is settled and written down for whether a Canvas-Next: may name a command that exits non-zero. tests/test_store.py assertRepairsRun enforces whichever rule that settled. python3 -m unittest discover -s tests -t . passes from a clean tree, and the new behaviour fails against the code as it stands before the change - demonstrated, not asserted.</text>
<text id="fdzu" v="1">Branch base, and it is not main. Everything this todo cites exists only on origin/errors/actionable-refusal-surface, the branch of the still-open PR #8 for the parent todo 10326884685. On main there is no canvas/refusal.py at all, and canvas/store.py contains neither _cannot_read_repository nor _cannot_read - checked by git ls-tree and git show, both counts zero. So errno-on-repository-refusals is cut from origin/errors/actionable-refusal-surface at cd8d90e, and any half of this work branched from main names files that are not there. The suite on that branch is 263 tests, not main's 189.</text>
<section id="hp9p" v="1" title="Open question 1 - is a repository that vanished a 2 where a canvas file that vanished is a 1?">
<question id="t8zw" v="1">Should _cannot_read_repository return exit 1 for ENOENT, the way its sibling _cannot_read now does, or is a repository that vanished genuinely a different kind of failure from a canvas file that vanished, and so still a 2?</question>
<text id="bv2j" v="1">Observed, before anything was changed. Both routes the todo names were run. EACCES (chmod 000 on .git) gives exit 2 and that is right. The vanished-repository route - .git removed between is_repository's os.stat and head_sha's rev-parse, simulated the way the parent todo's test does - gives exit 2 with 'cannot tell whether there are any commits in <dir>: looking at it was refused: [Errno 2] No such file or directory', an aftermath of 'what that repository holds is still unknown', a Canvas-About of 'errno 2 ENOENT', and a Canvas-Next whose repair is 'bin/canvas create <ledger-id> ...' - immediately under a Canvas-Exit that reads 'do not touch the canvas'. The exit code is arguable. Those last two lines are not: on ENOENT the tool can tell, it does know what the repository holds (nothing, because there is none), and a refusal that names a bin/canvas command as the repair cannot in the same breath say do not touch the canvas.</text>
<table id="uz6x" v="1">
<row id="s437" v="1">
<cell id="sm4b" v="1">Option</cell>
<cell id="zyrd" v="1">What it costs</cell>
</row>
<row id="fu7f" v="1">
<cell id="mkyr" v="1">A. Classify by errno, exactly as _cannot_read does: ENOENT returns the exit-1 refusal, every other errno stays a ToolProblem at exit 2.</cell>
<cell id="lgvs" v="2">The five call sites are not alike, and worse: the same fact already has an exit code. _not_a_repository (canvas/store.py:352) is what fires when the check itself finds no .git, and it is exit 2 - reproduced: 'state/canvas is not a git repository, so it has no sha to write against', Canvas-Exit 2, and its next action says 'a read never writes one'. Re-running the read does not fix it; only create does. So sending the racy ENOENT to exit 1 makes the exit code depend on which side of a race the caller landed - the exact disease _nothing_at's docstring says must not happen ('a race is the only difference between them, and the refusal a caller gets should not depend on which side of it they landed'). It would also send that caller to 're-read and re-decide' against a store where re-reading provably raises the same thing. Separately: is_repository's ENOENT never reaches this helper at all, because FileNotFoundError is caught above it and answered False.</cell>
</row>
<row id="pjt3" v="1">
<cell id="ymcz" v="1">B. Leave every errno at exit 2 and put the reason in README.md section Exit codes: a canvas file that is not there is a true statement about the store, while a canvas repository that is not there is the tool's own environment missing, and exit 2 is the code for that.</cell>
<cell id="smym" v="1">Two sibling helpers, sitting 170 lines apart, with visibly different rules for the same errno, and only a paragraph of README holding the difference in place. Nothing in the code enforces it, so the next person doing this refactor removes the special case again - which is how it came to be left out of the parent change in the first place. It also leaves the refusal saying 'what that repository holds is still unknown' at exit 2 in the one case where the errno said plainly that it holds nothing, because it is not there.</cell>
</row>
<row id="nyah" v="1">
<cell id="fbym" v="1">C. Split by call site: return exit 1 where the caller can act on the absence (is_repository) and exit 2 where it cannot (head_sha, the --base resolution, the ancestry check), by giving _cannot_read_repository a parameter that says which.</cell>
<cell id="rt82" v="1">This is classification by the guard the failure landed in, which is exactly the rule the parent change was made to remove. The same errno on the same directory would come back as two different exit codes depending on which command the caller happened to run, and a caller cannot see which guard it is inside. It also puts a sixth parameter on a helper with five call sites, and every one of them has to get it right for the rule to hold.</cell>
</row>
</table>
<text id="nf98" v="1">Where Case 1's code now stands, on branch errno-on-repository-refusals. _cannot_read_repository branches on errno.ENOENT and returns a new helper, _no_repository_at, which gives _not_a_repository's claim and _not_a_repository's repair in _not_a_repository's words - and at _not_a_repository's exit 2. So the option taken in code is B: a repository that vanished is a 2 where a canvas file that vanished is a 1, and README.md section Exit codes now says why in its own words. What the errno changed is what the tool says, not the code it exits with. EACCES is untouched and still says it cannot tell, because there the look really did fail. This node records what the code does; it does not close the question above it, which is still open and still carries all three options.</text>
</section>
<section id="y9hx" v="1" title="Open question 2 - may a Canvas-Next: line name a command that exits non-zero at all?">
<text id="mqxd" v="2">SETTLED, by the second writer, 2026-09-22: yes - a Canvas-Next: may name a command that exits non-zero, and one word says which one it may not. A command written after the word `run` is the repair: it is printed ready to run against real paths, running it is what makes the refused command work, and it exits 0. Everything else a next action names is either a diagnostic - `ls -ld`, `ls -l`, `df -h`, `ulimit -n`, there to show the state that produced the refusal - whose exit status is the answer and not a failure; or a form, a command with a <placeholder> in it that nobody runs as printed. So the rule the tool holds itself to is not 'every command a next action names succeeds' but 'every command a next action tells you to run succeeds'. The reason is not taste, it is what happened when I ran it. Option A - every command must exit 0 - is not implementable without gutting the surface: rendering all fifteen templates against a path that is genuinely gone and running every backticked command in each shows that four of them are not commands at all (`ulimit -n` is a shell builtin, `| cat | head -1` and `| head -1` are pipe fragments, `chown` is named bare with no operands) and that the ENOENT template's own repair exits 2 run verbatim, because it prints <ledger-id> where a ledger id goes. The remaining diagnostics exit 1 on precisely the condition their template exists for, because every way of looking at a path that is gone reports that it is gone by exiting non-zero. A would therefore either forbid a refusal about a missing path from telling a caller to look at it - the one thing a caller facing ENOENT most needs - or leave assertRepairsRun holding the hand-maintained allowlist that condition (3) was written to remove. B costs one marker, and the marker is syntactic rather than a list of command names, so a template that adds a repair nobody anticipated is covered the moment it is written.</text>
<table id="ehxj" v="1">
<row id="rysw" v="1">
<cell id="vp52" v="1">Option</cell>
<cell id="be5v" v="1">What it costs</cell>
</row>
<row id="vqpn" v="1">
<cell id="zksk" v="1">A. No. Every command a Canvas-Next: names must exit 0 when run against the state that produced the refusal. The `ls -ld` comes out of _OS_NEXT_ACTION[errno.ENOENT], and assertRepairsRun drops its chmod-only exemption and runs every command every template names.</cell>
<cell id="qdvs" v="1">A refusal can then only ever tell you to repair, never to look. The `ls -ld` on a missing path is not noise: its exit 1 and its 'No such file or directory' are the answer to which component of the path is gone, which is the thing a caller facing an ENOENT most wants to know and the thing bin/canvas cannot tell it. Dropping it means either finding a zero-exit way to ask the same question or accepting that the tool stops helping at the point the caller most needs it to.</cell>
</row>
<row id="yh66" v="1">
<cell id="vgke" v="2">CHOSEN. B. Yes, provided README.md section What a refusal prints says so and says how a caller tells the diagnostic from the repair - and provided the format carries that distinction somewhere a machine can read it, rather than leaving it to be inferred from the verb. As implemented: the distinction is the word `run` immediately in front of the command, README.md states it, and tests/test_store.py's assertRepairsRun reads it.</cell>
<cell id="lp37" v="2">What it cost, now that it has been paid rather than estimated. The estimate here was that telling the two apart means inventing a marker - a second trailer, a prefix, or a structure the line does not have - and that short of that assertRepairsRun keeps a hand-maintained list of commands it is allowed to run, which is the chmod-only exemption wearing a justification. Half right. A marker did have to be invented, but it cost one word in one template: _OS_NEXT_ACTION[errno.EACCES] is the only template in the whole table that names a command that is both runnable and a repair, so 'every existing template has to be classified against it' turned out to be one edit and not fifteen. And the marker is syntactic, not a list: assertRepairsRun runs whatever a next action marks with `run`, so a repair nobody anticipated is covered the moment somebody writes it. What is genuinely left over is that the marker is a word in prose rather than a trailer, so it is one careless sentence away from being dropped. The only thing holding it is the assertion in the other direction - every chmod a next action names must be marked - and that holds for chmod alone, because chmod is the one command in the surface that exists solely to make the refused command work. A second repair command that nobody marks would pass.</cell>
</row>
</table>
<text id="echr" v="2">For whoever takes Case 2, corrected - my first version of this node had the count wrong. Two things. (i) The reproduce command in the todo does not print what it says it does: `python3 bin/canvas read no-such-ledger 2>&1 | grep 'Canvas-Next:'` prints _nothing_at's next action, "create it with bin/canvas create no-such-ledger ...", and no ls at all, because that path never reaches refusal.os_next_action. (ii) _OS_NEXT_ACTION[errno.ENOENT] is reachable from far fewer places than grepping for os_next_action suggests. store.py has six calls to it, but four of them sit under an `except OSError` that a separate `except FileNotFoundError` above has already taken ENOENT away from - _no_canvas, the OPENCLAW_WORKSPACE stat, _write_and_commit's pre-write stat, and now _cannot_read_repository. Checked empirically, not by reading: spying on refusal.os_next_action and handing each helper a FileNotFoundError, exactly one errno 2 got through, from _cannot_write. So before Case 1's change the template had two reachable sites in store.py and now it has one, and that one is _cannot_write - which says in its own docstring that it is exit 2 for every errno, ENOENT included. Its Canvas-Next is the `ls -ld <state/canvas>` one. Case 2 is still live and still testable, including directly at the helper, the way test_an_unclassified_errno_still_refuses_in_the_shape already does.</text>
<text id="l32v" v="1">What running it showed, 2026-09-22, and two corrections to the todo's own text. I rendered every _OS_NEXT_ACTION template against a path that is genuinely gone and ran every backticked command each one names. Exit codes, verbatim: `ls -ld <gone>` 1; `ls -l <gone>` 1; `df -h <gone>` 1; `ulimit -n` 0; `chown` (named bare, no operands) 1; `bin/canvas create <ledger-id> --problem "<the problem>" --expected-value "<the expected value>"` 2, refused as 'not a usable ledger id'; `| cat | head -1` could not be run at all - [Errno 2] No such file or directory: '|'. Correction one: the todo says the repair in the ENOENT template 'succeeds and the parent todo's test runs it verbatim'. It does not succeed run verbatim, and the test does not run it. tests/test_store.py:4304 takes `bin/canvas create a-ledger-row` out of a different refusal - _nothing_at's, which fills the ledger id in - and then runs create with --problem P --expected-value V, substituting for the <the problem> placeholders by hand. Correction two: the ENOENT template says `ls -ld <path>` 'says which' directory on the way is missing. It does not. Checked both ways on the same machine: ls -ld prints one line and exits 1 whether the leaf is missing or a directory three levels up is, and the line names the path it was given either way. The diagnostic is still worth keeping - it distinguishes gone from unreadable, which is what a caller most needs - but it does not answer the question the template claims for it.</text>
<text id="ev4w" v="1">Where Case 2's code now stands, on branch errno-on-repository-refusals. canvas/refusal.py: the module docstring and the comment block over _OS_NEXT_ACTION state the rule and name the three kinds of thing a next action may hold - repair, diagnostic, form. _OS_NEXT_ACTION[errno.EACCES] is the only template in the table that names a command that is both runnable and a repair, and it now reads 'the repair is usually to run `chmod ...`' where it read '`chmod ...` is usually the repair'. No other template changed, because no other template names a runnable repair. README.md section What a refusal prints carries the rule in full, with the ls -ld exit 1 example and the bin/canvas create <ledger-id> form, and says which of the three a caller is looking at. tests/test_store.py assertRepairsRun no longer carries the chmod-only exemption: it runs every command a Canvas-Next: marks with `run`, whatever that command is, asserts it exits 0 and that it carries no <placeholder>, and asserts in the other direction that every chmod a next action names is marked as a repair - which is what stops the rule being satisfied by deleting the word. Demonstrated both ways rather than asserted. Against refusal.py exactly as it stood, the new assertion fails: 'named `chmod u+rx .../a-ledger-row.xml` without telling the caller to run it', 12 tests, FAILED (failures=1). With the change the same class is 12 tests OK and python3 -m unittest discover -s tests -t . is 263 tests OK. I also checked the assertion is not vacuous by pointing the marked repair at an invalid mode: it fails with '`chmod nosuchmode ...` is named as the repair and exited 1', so the command really is executed.</text>
<text id="g9ah" v="1">What the decision leaves open, named here so it is not mistaken for settled. (i) After this change _OS_NEXT_ACTION[errno.ENOENT] names no repair at all - a diagnostic and a form, and nothing marked `run`. That is allowed by the rule as settled, which says every command a next action tells you to run succeeds, not that every next action has a runnable repair to name. Whether a refusal ought to be required to name one is a different question and nothing in the repository asks it yet. (ii) The marker is a word in prose, not a trailer of its own, so it survives only as long as nobody rewrites the sentence around it. The single thing holding it is the converse assertion - every chmod a next action names must be marked - and that generalises to exactly one command, because chmod is the only one in the surface whose whole purpose is to make the refused command work. A second repair command that nobody marks would pass the suite. A Canvas-Repair: trailer beside Canvas-Next: would close that, at the cost of a sixth line in a block README describes as five. (iii) Both cases of todo 10329619223 are now answered on this branch, and the branch still does not descend from main - see node fdzu. A PR from it targets errors/actionable-refusal-surface, or waits for PR #8.</text>
<text id="qrpa" v="1">What the tool did about a second writer, recorded by the second writer. I arrived on this canvas holding e950b24a, the sha the first writer's handoff note names, and read it back before touching anything - it was still the head, so nothing had moved. After my own six edits I deliberately re-ran the edit to mqxd against e950b24a to see what the tool says to somebody who did not re-read. It took the hard branch: exit 1, 'refusing to write mqxd ... it moved in 1 commit(s) between --base e950b24a and 92361689, so this edit was decided against text that is no longer there. Nothing was applied and nothing was merged', then the intervening commit's subject, which is the whole --why of the edit that moved it, then git's own diff of the node from the old text to the new. Canvas-About: named the ledger id, the file, the --base I gave and the head; Canvas-Next: told me to read again, re-decide against the sha the read prints, and re-run with that --base. That is enough to act on without asking anybody: the reason the other writer changed it is in the output, so the re-decision can be made from the refusal itself rather than by reading the document again first. This node itself was inserted against the same stale e950b24a, which takes the soft branch instead - the write applies, and the same stdout that reports success carries Canvas-News and every intervening commit. What the tool does not carry either way is that somebody else is holding a base at all: read hands out a sha and says nothing about who wrote last or how old it is, so a second writer learns there was a first one from a Markdown file beside the canvas, not from the canvas.</text>
</section>
</canvas>
Note on completeness — the second writer
Every bin/canvas invocation I made by hand is above, in order, with its exit code and its
complete output. Fourteen of them: one read no-such-ledger, three against a throwaway
mktemp -d workspace reproducing the ENOENT repair, one verbatim-form create that exits 2,
two reads of the real canvas, six writes to it, and one deliberate stale---base probe that
was refused.
Two things I ran that are not bin/canvas invocations, named here so the corpus is not
misread as incomplete:
python3 - <<PY … from canvas import refusal …— two short import-path scripts that rendered every_OS_NEXT_ACTIONtemplate and ran the commands each one names. They read the module; they never touch a canvas or the store.python3 -m unittest …— the suite. It runsbin/canvasmany hundreds of times as a subprocess, each against its own temporary workspace. Those are the tests’ invocations, not mine, and none of them touches this run’s store.
The canvas store’s own git log is the authority on what changed the document: 43 commits, all
made by bin/canvas, working tree clean.
python3 bin/canvas replace bc-10329619223-errno-decides-the-repository-refusals t8zw --base e950b24a9d809d1be42a551c26c37b58fdf5380c --type text --text Settled, 2026-09-22, by the writer who opened this canvas and came back to it. A state/canvas repository that has vanished is exit 2, where a canvas file that has vanished is exit 1, and the errno decides what the refusal SAYS in both. Neither option as written on the table below is what the tree holds. Option A - classify _cannot_read_repository by errno the way _cannot_read is classified, and let ENOENT land on exit 1 - is rejected for its exit code. Option B - leave the helper unclassified for every errno and pay for it with a sentence in the README - is rejected for its silence in the code. What is in the tree is the half of each that is true: _cannot_read_repository branches on errno.ENOENT, and at ENOENT it returns _not_a_repository's claim, _not_a_repository's repair and _not_a_repository's words, at _not_a_repository's exit 2. The reason the code differs from the file case is that the two absences are not the same fact. A canvas that is not there is one missing file in a store that is otherwise intact, and the caller acts on it by creating that canvas - which is what exit 1 means. A state/canvas that is not there is the store itself, and that absence already has a code one syscall earlier: is_repository answers False for it and _not_a_repository refuses at 2. Sending the racy route to 1 would make the exit code a function of which side of a race the caller landed on, which is the disease the ENOENT rule exists to cure; it would just be the repository's race rather than the canvas file's. Exit 1 is also false advice here - it means re-read and re-decide, and a read never initialises the repository, so the re-read raises the same refusal forever. Condition (1) of todo 10329619223 is met the second way the condition allows: README.md section Exit codes states in its own words why a repository that vanished is 2 where a canvas file that vanished is 1. Checked on branch errno-on-repository-refusals before settling this: the docstring of _cannot_read_repository and README.md section Exit codes say the same thing, so neither had to be changed to make this settlement true. --why settling open question 1, the question this canvas was opened to hold. Deciding it on what the two absences actually are rather than on symmetry with _cannot_read: the file case's exit 1 is actionable because creating the canvas is the repair, and the repository case's exit 1 would be advice that cannot be taken, because a read never initialises the repository, so a caller who follows it re-reads forever. The reproduction is what settled it rather than the table - I came to this expecting to argue 1 against 2 and found that the arguable part was the code and the false part was the sentence. The question node becomes the answer because the tool has no way to mark a question answered while leaving it standing; what was asked is still in this node's history. Written against e950b24a, the base I last read this canvas at, on purpose: I want on the record what the tool says to a writer who comes back holding a sha that is seven commits old.
exit: 0
Canvas-Node: t8zw
Canvas-Base: fad921f83287af8aeb3996d672cc99db23808daf
Canvas-News: 7 commit(s) between e950b24a9d809d1be42a551c26c37b58fdf5380c and 2d7ae95c09c28d81cde89d14a5bc2b8b1713b5e7
replace mqxd: settling open question 2: a Canvas-Next may name a command that exits non-zero, but only a diagnostic or a form may, and the word 'run' marks the one that may not. Decided on evidence rather than on taste - running every command all fifteen _OS_NEXT_ACTION templates name showed four of them are not commands at all and that the ENOENT template's own repair exits 2 verbatim, so 'every command must exit 0' cannot be held without deleting the diagnostics that make an ENOENT refusal useful. The question node becomes the answer because the tool has no way to mark a question answered while leaving it standing; the question itself is still in this node's history.
replace vgke: marking on the options table itself which option the decision above took, because a reader who scrolls to the table should not have to reconstruct it from the prose. The tool has no way to mark a row chosen - there is no status on a node - so the word goes in the cell's own text, and the cell now also records how the option's proviso was actually met rather than leaving it as a condition nobody has checked.
replace lp37: correcting this cost cell against what the option actually cost to implement, the way the first writer corrected lgvs after running the other route. The estimate said every existing template would have to be classified and that the exemption would survive as an allowlist; in fact one template names a runnable repair and the marker is syntactic, so neither happened. But the estimate was right that the format carries no structure for this, and the residue it was pointing at is real and is now named precisely: the marker is prose and only the chmod converse check holds it.
insert l32v: the evidence the decision above stands on, written down as exit codes rather than as a claim, because the decision turns entirely on the observation that four of the things these templates name are not commands at all. Also the place two errors in the todo's own description get recorded: its Case 2 reproduce steps assert a repair runs verbatim that exits 2, and the template asserts a diagnostic answers a question it does not answer. A later reader checking my reasoning needs both, and neither is visible from the code.
insert ev4w: so that the next reader can tell what the decision above cost in code without reading the diff, and so that the two demonstrations condition (4) asks for - the new behaviour failing before and passing after - are recorded where the decision is rather than only in a commit message. The vacuity check is in here on purpose: an assertion that runs no command passes for the wrong reason, and the canvas should say that somebody looked.
insert g9ah: a decision that does not say what it left open reads later as if it covered everything, and the two loose ends here are both things a reviewer would otherwise have to find for themselves: the ENOENT template now names no repair, and the marker is prose held up by a check that generalises to one command. Naming the trailer that would close it, and what it would cost, so that whoever picks it up is deciding rather than rediscovering.
insert qrpa: the canvas is supposed to hold the shared understanding between the people and the agents on a task, and 'what happens when two of us write to it' is part of that understanding and was not in it. Recording what the staleness check actually did to me rather than what the README says it does, including the one thing it does not do: nothing in the tool told me another writer existed. Written against the first writer's base on purpose, so that the soft branch is demonstrated by the same edit that describes the hard one.
diff --git a/bc-10329619223-errno-decides-the-repository-refusals.xml b/bc-10329619223-errno-decides-the-repository-refusals.xml
index 4c0c5d5..7e14862 100644
--- a/bc-10329619223-errno-decides-the-repository-refusals.xml
+++ b/bc-10329619223-errno-decides-the-repository-refusals.xml
@@ -27,7 +27,7 @@
<text id="nf98" v="1">Where Case 1's code now stands, on branch errno-on-repository-refusals. _cannot_read_repository branches on errno.ENOENT and returns a new helper, _no_repository_at, which gives _not_a_repository's claim and _not_a_repository's repair in _not_a_repository's words - and at _not_a_repository's exit 2. So the option taken in code is B: a repository that vanished is a 2 where a canvas file that vanished is a 1, and README.md section Exit codes now says why in its own words. What the errno changed is what the tool says, not the code it exits with. EACCES is untouched and still says it cannot tell, because there the look really did fail. This node records what the code does; it does not close the question above it, which is still open and still carries all three options.</text>
</section>
<section id="y9hx" v="1" title="Open question 2 - may a Canvas-Next: line name a command that exits non-zero at all?">
- <question id="mqxd" v="1">May a Canvas-Next: name a command that exits non-zero at all? _OS_NEXT_ACTION[errno.ENOENT] says `ls -ld <path>` says which, and on a path that is genuinely gone that ls exits 1. The repair in the same template - bin/canvas create ... - succeeds. So this is not a broken repair; it is whether a next action may ever be a diagnostic rather than a repair.</question>
+ <text id="mqxd" v="2">SETTLED, by the second writer, 2026-09-22: yes - a Canvas-Next: may name a command that exits non-zero, and one word says which one it may not. A command written after the word `run` is the repair: it is printed ready to run against real paths, running it is what makes the refused command work, and it exits 0. Everything else a next action names is either a diagnostic - `ls -ld`, `ls -l`, `df -h`, `ulimit -n`, there to show the state that produced the refusal - whose exit status is the answer and not a failure; or a form, a command with a <placeholder> in it that nobody runs as printed. So the rule the tool holds itself to is not 'every command a next action names succeeds' but 'every command a next action tells you to run succeeds'. The reason is not taste, it is what happened when I ran it. Option A - every command must exit 0 - is not implementable without gutting the surface: rendering all fifteen templates against a path that is genuinely gone and running every backticked command in each shows that four of them are not commands at all (`ulimit -n` is a shell builtin, `| cat | head -1` and `| head -1` are pipe fragments, `chown` is named bare with no operands) and that the ENOENT template's own repair exits 2 run verbatim, because it prints <ledger-id> where a ledger id goes. The remaining diagnostics exit 1 on precisely the condition their template exists for, because every way of looking at a path that is gone reports that it is gone by exiting non-zero. A would therefore either forbid a refusal about a missing path from telling a caller to look at it - the one thing a caller facing ENOENT most needs - or leave assertRepairsRun holding the hand-maintained allowlist that condition (3) was written to remove. B costs one marker, and the marker is syntactic rather than a list of command names, so a template that adds a repair nobody anticipated is covered the moment it is written.</text>
<table id="ehxj" v="1">
<row id="rysw" v="1">
<cell id="vp52" v="1">Option</cell>
@@ -38,10 +38,14 @@
<cell id="qdvs" v="1">A refusal can then only ever tell you to repair, never to look. The `ls -ld` on a missing path is not noise: its exit 1 and its 'No such file or directory' are the answer to which component of the path is gone, which is the thing a caller facing an ENOENT most wants to know and the thing bin/canvas cannot tell it. Dropping it means either finding a zero-exit way to ask the same question or accepting that the tool stops helping at the point the caller most needs it to.</cell>
</row>
<row id="yh66" v="1">
- <cell id="vgke" v="1">B. Yes, provided README.md section What a refusal prints says so and says how a caller tells the diagnostic from the repair - and provided the format carries that distinction somewhere a machine can read it, rather than leaving it to be inferred from the verb.</cell>
- <cell id="lp37" v="1">Canvas-Next: is one line of prose with no marker on it, so telling the two apart means inventing one - a second trailer, a prefix, or a structure the line does not currently have - and every existing template has to be classified against it. Short of that, assertRepairsRun keeps a hand-maintained list of which commands it is allowed to run, which is what the chmod-only exemption already is: the thing condition (3) was written to remove stays, wearing a justification.</cell>
+ <cell id="vgke" v="2">CHOSEN. B. Yes, provided README.md section What a refusal prints says so and says how a caller tells the diagnostic from the repair - and provided the format carries that distinction somewhere a machine can read it, rather than leaving it to be inferred from the verb. As implemented: the distinction is the word `run` immediately in front of the command, README.md states it, and tests/test_store.py's assertRepairsRun reads it.</cell>
+ <cell id="lp37" v="2">What it cost, now that it has been paid rather than estimated. The estimate here was that telling the two apart means inventing a marker - a second trailer, a prefix, or a structure the line does not have - and that short of that assertRepairsRun keeps a hand-maintained list of commands it is allowed to run, which is the chmod-only exemption wearing a justification. Half right. A marker did have to be invented, but it cost one word in one template: _OS_NEXT_ACTION[errno.EACCES] is the only template in the whole table that names a command that is both runnable and a repair, so 'every existing template has to be classified against it' turned out to be one edit and not fifteen. And the marker is syntactic, not a list: assertRepairsRun runs whatever a next action marks with `run`, so a repair nobody anticipated is covered the moment somebody writes it. What is genuinely left over is that the marker is a word in prose rather than a trailer, so it is one careless sentence away from being dropped. The only thing holding it is the assertion in the other direction - every chmod a next action names must be marked - and that holds for chmod alone, because chmod is the one command in the surface that exists solely to make the refused command work. A second repair command that nobody marks would pass.</cell>
</row>
</table>
<text id="echr" v="2">For whoever takes Case 2, corrected - my first version of this node had the count wrong. Two things. (i) The reproduce command in the todo does not print what it says it does: `python3 bin/canvas read no-such-ledger 2>&1 | grep 'Canvas-Next:'` prints _nothing_at's next action, "create it with bin/canvas create no-such-ledger ...", and no ls at all, because that path never reaches refusal.os_next_action. (ii) _OS_NEXT_ACTION[errno.ENOENT] is reachable from far fewer places than grepping for os_next_action suggests. store.py has six calls to it, but four of them sit under an `except OSError` that a separate `except FileNotFoundError` above has already taken ENOENT away from - _no_canvas, the OPENCLAW_WORKSPACE stat, _write_and_commit's pre-write stat, and now _cannot_read_repository. Checked empirically, not by reading: spying on refusal.os_next_action and handing each helper a FileNotFoundError, exactly one errno 2 got through, from _cannot_write. So before Case 1's change the template had two reachable sites in store.py and now it has one, and that one is _cannot_write - which says in its own docstring that it is exit 2 for every errno, ENOENT included. Its Canvas-Next is the `ls -ld <state/canvas>` one. Case 2 is still live and still testable, including directly at the helper, the way test_an_unclassified_errno_still_refuses_in_the_shape already does.</text>
+ <text id="l32v" v="1">What running it showed, 2026-09-22, and two corrections to the todo's own text. I rendered every _OS_NEXT_ACTION template against a path that is genuinely gone and ran every backticked command each one names. Exit codes, verbatim: `ls -ld <gone>` 1; `ls -l <gone>` 1; `df -h <gone>` 1; `ulimit -n` 0; `chown` (named bare, no operands) 1; `bin/canvas create <ledger-id> --problem "<the problem>" --expected-value "<the expected value>"` 2, refused as 'not a usable ledger id'; `| cat | head -1` could not be run at all - [Errno 2] No such file or directory: '|'. Correction one: the todo says the repair in the ENOENT template 'succeeds and the parent todo's test runs it verbatim'. It does not succeed run verbatim, and the test does not run it. tests/test_store.py:4304 takes `bin/canvas create a-ledger-row` out of a different refusal - _nothing_at's, which fills the ledger id in - and then runs create with --problem P --expected-value V, substituting for the <the problem> placeholders by hand. Correction two: the ENOENT template says `ls -ld <path>` 'says which' directory on the way is missing. It does not. Checked both ways on the same machine: ls -ld prints one line and exits 1 whether the leaf is missing or a directory three levels up is, and the line names the path it was given either way. The diagnostic is still worth keeping - it distinguishes gone from unreadable, which is what a caller most needs - but it does not answer the question the template claims for it.</text>
+ <text id="ev4w" v="1">Where Case 2's code now stands, on branch errno-on-repository-refusals. canvas/refusal.py: the module docstring and the comment block over _OS_NEXT_ACTION state the rule and name the three kinds of thing a next action may hold - repair, diagnostic, form. _OS_NEXT_ACTION[errno.EACCES] is the only template in the table that names a command that is both runnable and a repair, and it now reads 'the repair is usually to run `chmod ...`' where it read '`chmod ...` is usually the repair'. No other template changed, because no other template names a runnable repair. README.md section What a refusal prints carries the rule in full, with the ls -ld exit 1 example and the bin/canvas create <ledger-id> form, and says which of the three a caller is looking at. tests/test_store.py assertRepairsRun no longer carries the chmod-only exemption: it runs every command a Canvas-Next: marks with `run`, whatever that command is, asserts it exits 0 and that it carries no <placeholder>, and asserts in the other direction that every chmod a next action names is marked as a repair - which is what stops the rule being satisfied by deleting the word. Demonstrated both ways rather than asserted. Against refusal.py exactly as it stood, the new assertion fails: 'named `chmod u+rx .../a-ledger-row.xml` without telling the caller to run it', 12 tests, FAILED (failures=1). With the change the same class is 12 tests OK and python3 -m unittest discover -s tests -t . is 263 tests OK. I also checked the assertion is not vacuous by pointing the marked repair at an invalid mode: it fails with '`chmod nosuchmode ...` is named as the repair and exited 1', so the command really is executed.</text>
+ <text id="g9ah" v="1">What the decision leaves open, named here so it is not mistaken for settled. (i) After this change _OS_NEXT_ACTION[errno.ENOENT] names no repair at all - a diagnostic and a form, and nothing marked `run`. That is allowed by the rule as settled, which says every command a next action tells you to run succeeds, not that every next action has a runnable repair to name. Whether a refusal ought to be required to name one is a different question and nothing in the repository asks it yet. (ii) The marker is a word in prose, not a trailer of its own, so it survives only as long as nobody rewrites the sentence around it. The single thing holding it is the converse assertion - every chmod a next action names must be marked - and that generalises to exactly one command, because chmod is the only one in the surface whose whole purpose is to make the refused command work. A second repair command that nobody marks would pass the suite. A Canvas-Repair: trailer beside Canvas-Next: would close that, at the cost of a sixth line in a block README describes as five. (iii) Both cases of todo 10329619223 are now answered on this branch, and the branch still does not descend from main - see node fdzu. A PR from it targets errors/actionable-refusal-surface, or waits for PR #8.</text>
+ <text id="qrpa" v="1">What the tool did about a second writer, recorded by the second writer. I arrived on this canvas holding e950b24a, the sha the first writer's handoff note names, and read it back before touching anything - it was still the head, so nothing had moved. After my own six edits I deliberately re-ran the edit to mqxd against e950b24a to see what the tool says to somebody who did not re-read. It took the hard branch: exit 1, 'refusing to write mqxd ... it moved in 1 commit(s) between --base e950b24a and 92361689, so this edit was decided against text that is no longer there. Nothing was applied and nothing was merged', then the intervening commit's subject, which is the whole --why of the edit that moved it, then git's own diff of the node from the old text to the new. Canvas-About: named the ledger id, the file, the --base I gave and the head; Canvas-Next: told me to read again, re-decide against the sha the read prints, and re-run with that --base. That is enough to act on without asking anybody: the reason the other writer changed it is in the output, so the re-decision can be made from the refusal itself rather than by reading the document again first. This node itself was inserted against the same stale e950b24a, which takes the soft branch instead - the write applies, and the same stdout that reports success carries Canvas-News and every intervening commit. What the tool does not carry either way is that somebody else is holding a base at all: read hands out a sha and says nothing about who wrote last or how old it is, so a second writer learns there was a first one from a Markdown file beside the canvas, not from the canvas.</text>
</section>
</canvas>
python3 bin/canvas read bc-10329619223-errno-decides-the-repository-refusals
exit: 0
Canvas-Base: fad921f83287af8aeb3996d672cc99db23808daf
<?xml version="1.0" encoding="UTF-8"?>
<canvas ledger="bc-10329619223-errno-decides-the-repository-refusals" schema="1">
<text id="bpx2" v="1">The parent change made every refusal's exit code, its repair and whatever it claims about the store derive from the errno the operating system actually returned, rather than from the guard the failure happened to land in - but one refusal helper and one next-action template were left outside that rule. canvas/store.py:582 _cannot_read_repository returns ToolProblem, exit 2, for every errno including ENOENT, where its sibling _cannot_read now returns exit 1 for ENOENT. canvas/refusal.py _OS_NEXT_ACTION[errno.ENOENT] says `ls -ld <path>` says which, and on a path that is genuinely gone that ls exits 1.</text>
<text id="bcr2" v="1">Every refusal helper in canvas/store.py that is handed an OSError chooses its exit code from the errno, _cannot_read_repository included - or README.md section Exit codes states, in its own words, why a repository that vanished is 2 where a canvas file that vanished is 1. A rule is settled and written down for whether a Canvas-Next: may name a command that exits non-zero. tests/test_store.py assertRepairsRun enforces whichever rule that settled. python3 -m unittest discover -s tests -t . passes from a clean tree, and the new behaviour fails against the code as it stands before the change - demonstrated, not asserted.</text>
<text id="fdzu" v="1">Branch base, and it is not main. Everything this todo cites exists only on origin/errors/actionable-refusal-surface, the branch of the still-open PR #8 for the parent todo 10326884685. On main there is no canvas/refusal.py at all, and canvas/store.py contains neither _cannot_read_repository nor _cannot_read - checked by git ls-tree and git show, both counts zero. So errno-on-repository-refusals is cut from origin/errors/actionable-refusal-surface at cd8d90e, and any half of this work branched from main names files that are not there. The suite on that branch is 263 tests, not main's 189.</text>
<section id="hp9p" v="1" title="Open question 1 - is a repository that vanished a 2 where a canvas file that vanished is a 1?">
<text id="t8zw" v="2">Settled, 2026-09-22, by the writer who opened this canvas and came back to it. A state/canvas repository that has vanished is exit 2, where a canvas file that has vanished is exit 1, and the errno decides what the refusal SAYS in both. Neither option as written on the table below is what the tree holds. Option A - classify _cannot_read_repository by errno the way _cannot_read is classified, and let ENOENT land on exit 1 - is rejected for its exit code. Option B - leave the helper unclassified for every errno and pay for it with a sentence in the README - is rejected for its silence in the code. What is in the tree is the half of each that is true: _cannot_read_repository branches on errno.ENOENT, and at ENOENT it returns _not_a_repository's claim, _not_a_repository's repair and _not_a_repository's words, at _not_a_repository's exit 2. The reason the code differs from the file case is that the two absences are not the same fact. A canvas that is not there is one missing file in a store that is otherwise intact, and the caller acts on it by creating that canvas - which is what exit 1 means. A state/canvas that is not there is the store itself, and that absence already has a code one syscall earlier: is_repository answers False for it and _not_a_repository refuses at 2. Sending the racy route to 1 would make the exit code a function of which side of a race the caller landed on, which is the disease the ENOENT rule exists to cure; it would just be the repository's race rather than the canvas file's. Exit 1 is also false advice here - it means re-read and re-decide, and a read never initialises the repository, so the re-read raises the same refusal forever. Condition (1) of todo 10329619223 is met the second way the condition allows: README.md section Exit codes states in its own words why a repository that vanished is 2 where a canvas file that vanished is 1. Checked on branch errno-on-repository-refusals before settling this: the docstring of _cannot_read_repository and README.md section Exit codes say the same thing, so neither had to be changed to make this settlement true.</text>
<text id="bv2j" v="1">Observed, before anything was changed. Both routes the todo names were run. EACCES (chmod 000 on .git) gives exit 2 and that is right. The vanished-repository route - .git removed between is_repository's os.stat and head_sha's rev-parse, simulated the way the parent todo's test does - gives exit 2 with 'cannot tell whether there are any commits in <dir>: looking at it was refused: [Errno 2] No such file or directory', an aftermath of 'what that repository holds is still unknown', a Canvas-About of 'errno 2 ENOENT', and a Canvas-Next whose repair is 'bin/canvas create <ledger-id> ...' - immediately under a Canvas-Exit that reads 'do not touch the canvas'. The exit code is arguable. Those last two lines are not: on ENOENT the tool can tell, it does know what the repository holds (nothing, because there is none), and a refusal that names a bin/canvas command as the repair cannot in the same breath say do not touch the canvas.</text>
<table id="uz6x" v="1">
<row id="s437" v="1">
<cell id="sm4b" v="1">Option</cell>
<cell id="zyrd" v="1">What it costs</cell>
</row>
<row id="fu7f" v="1">
<cell id="mkyr" v="1">A. Classify by errno, exactly as _cannot_read does: ENOENT returns the exit-1 refusal, every other errno stays a ToolProblem at exit 2.</cell>
<cell id="lgvs" v="2">The five call sites are not alike, and worse: the same fact already has an exit code. _not_a_repository (canvas/store.py:352) is what fires when the check itself finds no .git, and it is exit 2 - reproduced: 'state/canvas is not a git repository, so it has no sha to write against', Canvas-Exit 2, and its next action says 'a read never writes one'. Re-running the read does not fix it; only create does. So sending the racy ENOENT to exit 1 makes the exit code depend on which side of a race the caller landed - the exact disease _nothing_at's docstring says must not happen ('a race is the only difference between them, and the refusal a caller gets should not depend on which side of it they landed'). It would also send that caller to 're-read and re-decide' against a store where re-reading provably raises the same thing. Separately: is_repository's ENOENT never reaches this helper at all, because FileNotFoundError is caught above it and answered False.</cell>
</row>
<row id="pjt3" v="1">
<cell id="ymcz" v="1">B. Leave every errno at exit 2 and put the reason in README.md section Exit codes: a canvas file that is not there is a true statement about the store, while a canvas repository that is not there is the tool's own environment missing, and exit 2 is the code for that.</cell>
<cell id="smym" v="1">Two sibling helpers, sitting 170 lines apart, with visibly different rules for the same errno, and only a paragraph of README holding the difference in place. Nothing in the code enforces it, so the next person doing this refactor removes the special case again - which is how it came to be left out of the parent change in the first place. It also leaves the refusal saying 'what that repository holds is still unknown' at exit 2 in the one case where the errno said plainly that it holds nothing, because it is not there.</cell>
</row>
<row id="nyah" v="1">
<cell id="fbym" v="1">C. Split by call site: return exit 1 where the caller can act on the absence (is_repository) and exit 2 where it cannot (head_sha, the --base resolution, the ancestry check), by giving _cannot_read_repository a parameter that says which.</cell>
<cell id="rt82" v="1">This is classification by the guard the failure landed in, which is exactly the rule the parent change was made to remove. The same errno on the same directory would come back as two different exit codes depending on which command the caller happened to run, and a caller cannot see which guard it is inside. It also puts a sixth parameter on a helper with five call sites, and every one of them has to get it right for the rule to hold.</cell>
</row>
</table>
<text id="nf98" v="1">Where Case 1's code now stands, on branch errno-on-repository-refusals. _cannot_read_repository branches on errno.ENOENT and returns a new helper, _no_repository_at, which gives _not_a_repository's claim and _not_a_repository's repair in _not_a_repository's words - and at _not_a_repository's exit 2. So the option taken in code is B: a repository that vanished is a 2 where a canvas file that vanished is a 1, and README.md section Exit codes now says why in its own words. What the errno changed is what the tool says, not the code it exits with. EACCES is untouched and still says it cannot tell, because there the look really did fail. This node records what the code does; it does not close the question above it, which is still open and still carries all three options.</text>
</section>
<section id="y9hx" v="1" title="Open question 2 - may a Canvas-Next: line name a command that exits non-zero at all?">
<text id="mqxd" v="2">SETTLED, by the second writer, 2026-09-22: yes - a Canvas-Next: may name a command that exits non-zero, and one word says which one it may not. A command written after the word `run` is the repair: it is printed ready to run against real paths, running it is what makes the refused command work, and it exits 0. Everything else a next action names is either a diagnostic - `ls -ld`, `ls -l`, `df -h`, `ulimit -n`, there to show the state that produced the refusal - whose exit status is the answer and not a failure; or a form, a command with a <placeholder> in it that nobody runs as printed. So the rule the tool holds itself to is not 'every command a next action names succeeds' but 'every command a next action tells you to run succeeds'. The reason is not taste, it is what happened when I ran it. Option A - every command must exit 0 - is not implementable without gutting the surface: rendering all fifteen templates against a path that is genuinely gone and running every backticked command in each shows that four of them are not commands at all (`ulimit -n` is a shell builtin, `| cat | head -1` and `| head -1` are pipe fragments, `chown` is named bare with no operands) and that the ENOENT template's own repair exits 2 run verbatim, because it prints <ledger-id> where a ledger id goes. The remaining diagnostics exit 1 on precisely the condition their template exists for, because every way of looking at a path that is gone reports that it is gone by exiting non-zero. A would therefore either forbid a refusal about a missing path from telling a caller to look at it - the one thing a caller facing ENOENT most needs - or leave assertRepairsRun holding the hand-maintained allowlist that condition (3) was written to remove. B costs one marker, and the marker is syntactic rather than a list of command names, so a template that adds a repair nobody anticipated is covered the moment it is written.</text>
<table id="ehxj" v="1">
<row id="rysw" v="1">
<cell id="vp52" v="1">Option</cell>
<cell id="be5v" v="1">What it costs</cell>
</row>
<row id="vqpn" v="1">
<cell id="zksk" v="1">A. No. Every command a Canvas-Next: names must exit 0 when run against the state that produced the refusal. The `ls -ld` comes out of _OS_NEXT_ACTION[errno.ENOENT], and assertRepairsRun drops its chmod-only exemption and runs every command every template names.</cell>
<cell id="qdvs" v="1">A refusal can then only ever tell you to repair, never to look. The `ls -ld` on a missing path is not noise: its exit 1 and its 'No such file or directory' are the answer to which component of the path is gone, which is the thing a caller facing an ENOENT most wants to know and the thing bin/canvas cannot tell it. Dropping it means either finding a zero-exit way to ask the same question or accepting that the tool stops helping at the point the caller most needs it to.</cell>
</row>
<row id="yh66" v="1">
<cell id="vgke" v="2">CHOSEN. B. Yes, provided README.md section What a refusal prints says so and says how a caller tells the diagnostic from the repair - and provided the format carries that distinction somewhere a machine can read it, rather than leaving it to be inferred from the verb. As implemented: the distinction is the word `run` immediately in front of the command, README.md states it, and tests/test_store.py's assertRepairsRun reads it.</cell>
<cell id="lp37" v="2">What it cost, now that it has been paid rather than estimated. The estimate here was that telling the two apart means inventing a marker - a second trailer, a prefix, or a structure the line does not have - and that short of that assertRepairsRun keeps a hand-maintained list of commands it is allowed to run, which is the chmod-only exemption wearing a justification. Half right. A marker did have to be invented, but it cost one word in one template: _OS_NEXT_ACTION[errno.EACCES] is the only template in the whole table that names a command that is both runnable and a repair, so 'every existing template has to be classified against it' turned out to be one edit and not fifteen. And the marker is syntactic, not a list: assertRepairsRun runs whatever a next action marks with `run`, so a repair nobody anticipated is covered the moment somebody writes it. What is genuinely left over is that the marker is a word in prose rather than a trailer, so it is one careless sentence away from being dropped. The only thing holding it is the assertion in the other direction - every chmod a next action names must be marked - and that holds for chmod alone, because chmod is the one command in the surface that exists solely to make the refused command work. A second repair command that nobody marks would pass.</cell>
</row>
</table>
<text id="echr" v="2">For whoever takes Case 2, corrected - my first version of this node had the count wrong. Two things. (i) The reproduce command in the todo does not print what it says it does: `python3 bin/canvas read no-such-ledger 2>&1 | grep 'Canvas-Next:'` prints _nothing_at's next action, "create it with bin/canvas create no-such-ledger ...", and no ls at all, because that path never reaches refusal.os_next_action. (ii) _OS_NEXT_ACTION[errno.ENOENT] is reachable from far fewer places than grepping for os_next_action suggests. store.py has six calls to it, but four of them sit under an `except OSError` that a separate `except FileNotFoundError` above has already taken ENOENT away from - _no_canvas, the OPENCLAW_WORKSPACE stat, _write_and_commit's pre-write stat, and now _cannot_read_repository. Checked empirically, not by reading: spying on refusal.os_next_action and handing each helper a FileNotFoundError, exactly one errno 2 got through, from _cannot_write. So before Case 1's change the template had two reachable sites in store.py and now it has one, and that one is _cannot_write - which says in its own docstring that it is exit 2 for every errno, ENOENT included. Its Canvas-Next is the `ls -ld <state/canvas>` one. Case 2 is still live and still testable, including directly at the helper, the way test_an_unclassified_errno_still_refuses_in_the_shape already does.</text>
<text id="l32v" v="1">What running it showed, 2026-09-22, and two corrections to the todo's own text. I rendered every _OS_NEXT_ACTION template against a path that is genuinely gone and ran every backticked command each one names. Exit codes, verbatim: `ls -ld <gone>` 1; `ls -l <gone>` 1; `df -h <gone>` 1; `ulimit -n` 0; `chown` (named bare, no operands) 1; `bin/canvas create <ledger-id> --problem "<the problem>" --expected-value "<the expected value>"` 2, refused as 'not a usable ledger id'; `| cat | head -1` could not be run at all - [Errno 2] No such file or directory: '|'. Correction one: the todo says the repair in the ENOENT template 'succeeds and the parent todo's test runs it verbatim'. It does not succeed run verbatim, and the test does not run it. tests/test_store.py:4304 takes `bin/canvas create a-ledger-row` out of a different refusal - _nothing_at's, which fills the ledger id in - and then runs create with --problem P --expected-value V, substituting for the <the problem> placeholders by hand. Correction two: the ENOENT template says `ls -ld <path>` 'says which' directory on the way is missing. It does not. Checked both ways on the same machine: ls -ld prints one line and exits 1 whether the leaf is missing or a directory three levels up is, and the line names the path it was given either way. The diagnostic is still worth keeping - it distinguishes gone from unreadable, which is what a caller most needs - but it does not answer the question the template claims for it.</text>
<text id="ev4w" v="1">Where Case 2's code now stands, on branch errno-on-repository-refusals. canvas/refusal.py: the module docstring and the comment block over _OS_NEXT_ACTION state the rule and name the three kinds of thing a next action may hold - repair, diagnostic, form. _OS_NEXT_ACTION[errno.EACCES] is the only template in the table that names a command that is both runnable and a repair, and it now reads 'the repair is usually to run `chmod ...`' where it read '`chmod ...` is usually the repair'. No other template changed, because no other template names a runnable repair. README.md section What a refusal prints carries the rule in full, with the ls -ld exit 1 example and the bin/canvas create <ledger-id> form, and says which of the three a caller is looking at. tests/test_store.py assertRepairsRun no longer carries the chmod-only exemption: it runs every command a Canvas-Next: marks with `run`, whatever that command is, asserts it exits 0 and that it carries no <placeholder>, and asserts in the other direction that every chmod a next action names is marked as a repair - which is what stops the rule being satisfied by deleting the word. Demonstrated both ways rather than asserted. Against refusal.py exactly as it stood, the new assertion fails: 'named `chmod u+rx .../a-ledger-row.xml` without telling the caller to run it', 12 tests, FAILED (failures=1). With the change the same class is 12 tests OK and python3 -m unittest discover -s tests -t . is 263 tests OK. I also checked the assertion is not vacuous by pointing the marked repair at an invalid mode: it fails with '`chmod nosuchmode ...` is named as the repair and exited 1', so the command really is executed.</text>
<text id="g9ah" v="1">What the decision leaves open, named here so it is not mistaken for settled. (i) After this change _OS_NEXT_ACTION[errno.ENOENT] names no repair at all - a diagnostic and a form, and nothing marked `run`. That is allowed by the rule as settled, which says every command a next action tells you to run succeeds, not that every next action has a runnable repair to name. Whether a refusal ought to be required to name one is a different question and nothing in the repository asks it yet. (ii) The marker is a word in prose, not a trailer of its own, so it survives only as long as nobody rewrites the sentence around it. The single thing holding it is the converse assertion - every chmod a next action names must be marked - and that generalises to exactly one command, because chmod is the only one in the surface whose whole purpose is to make the refused command work. A second repair command that nobody marks would pass the suite. A Canvas-Repair: trailer beside Canvas-Next: would close that, at the cost of a sixth line in a block README describes as five. (iii) Both cases of todo 10329619223 are now answered on this branch, and the branch still does not descend from main - see node fdzu. A PR from it targets errors/actionable-refusal-surface, or waits for PR #8.</text>
<text id="qrpa" v="1">What the tool did about a second writer, recorded by the second writer. I arrived on this canvas holding e950b24a, the sha the first writer's handoff note names, and read it back before touching anything - it was still the head, so nothing had moved. After my own six edits I deliberately re-ran the edit to mqxd against e950b24a to see what the tool says to somebody who did not re-read. It took the hard branch: exit 1, 'refusing to write mqxd ... it moved in 1 commit(s) between --base e950b24a and 92361689, so this edit was decided against text that is no longer there. Nothing was applied and nothing was merged', then the intervening commit's subject, which is the whole --why of the edit that moved it, then git's own diff of the node from the old text to the new. Canvas-About: named the ledger id, the file, the --base I gave and the head; Canvas-Next: told me to read again, re-decide against the sha the read prints, and re-run with that --base. That is enough to act on without asking anybody: the reason the other writer changed it is in the output, so the re-decision can be made from the refusal itself rather than by reading the document again first. This node itself was inserted against the same stale e950b24a, which takes the soft branch instead - the write applies, and the same stdout that reports success carries Canvas-News and every intervening commit. What the tool does not carry either way is that somebody else is holding a base at all: read hands out a sha and says nothing about who wrote last or how old it is, so a second writer learns there was a first one from a Markdown file beside the canvas, not from the canvas.</text>
</section>
</canvas>
python3 bin/canvas read bc-10329619223-errno-decides-the-repository-refusals
exit: 0
Canvas-Base: fad921f83287af8aeb3996d672cc99db23808daf
<?xml version="1.0" encoding="UTF-8"?>
<canvas ledger="bc-10329619223-errno-decides-the-repository-refusals" schema="1">
<text id="bpx2" v="1">The parent change made every refusal's exit code, its repair and whatever it claims about the store derive from the errno the operating system actually returned, rather than from the guard the failure happened to land in - but one refusal helper and one next-action template were left outside that rule. canvas/store.py:582 _cannot_read_repository returns ToolProblem, exit 2, for every errno including ENOENT, where its sibling _cannot_read now returns exit 1 for ENOENT. canvas/refusal.py _OS_NEXT_ACTION[errno.ENOENT] says `ls -ld <path>` says which, and on a path that is genuinely gone that ls exits 1.</text>
<text id="bcr2" v="1">Every refusal helper in canvas/store.py that is handed an OSError chooses its exit code from the errno, _cannot_read_repository included - or README.md section Exit codes states, in its own words, why a repository that vanished is 2 where a canvas file that vanished is 1. A rule is settled and written down for whether a Canvas-Next: may name a command that exits non-zero. tests/test_store.py assertRepairsRun enforces whichever rule that settled. python3 -m unittest discover -s tests -t . passes from a clean tree, and the new behaviour fails against the code as it stands before the change - demonstrated, not asserted.</text>
<text id="fdzu" v="1">Branch base, and it is not main. Everything this todo cites exists only on origin/errors/actionable-refusal-surface, the branch of the still-open PR #8 for the parent todo 10326884685. On main there is no canvas/refusal.py at all, and canvas/store.py contains neither _cannot_read_repository nor _cannot_read - checked by git ls-tree and git show, both counts zero. So errno-on-repository-refusals is cut from origin/errors/actionable-refusal-surface at cd8d90e, and any half of this work branched from main names files that are not there. The suite on that branch is 263 tests, not main's 189.</text>
<section id="hp9p" v="1" title="Open question 1 - is a repository that vanished a 2 where a canvas file that vanished is a 1?">
<text id="t8zw" v="2">Settled, 2026-09-22, by the writer who opened this canvas and came back to it. A state/canvas repository that has vanished is exit 2, where a canvas file that has vanished is exit 1, and the errno decides what the refusal SAYS in both. Neither option as written on the table below is what the tree holds. Option A - classify _cannot_read_repository by errno the way _cannot_read is classified, and let ENOENT land on exit 1 - is rejected for its exit code. Option B - leave the helper unclassified for every errno and pay for it with a sentence in the README - is rejected for its silence in the code. What is in the tree is the half of each that is true: _cannot_read_repository branches on errno.ENOENT, and at ENOENT it returns _not_a_repository's claim, _not_a_repository's repair and _not_a_repository's words, at _not_a_repository's exit 2. The reason the code differs from the file case is that the two absences are not the same fact. A canvas that is not there is one missing file in a store that is otherwise intact, and the caller acts on it by creating that canvas - which is what exit 1 means. A state/canvas that is not there is the store itself, and that absence already has a code one syscall earlier: is_repository answers False for it and _not_a_repository refuses at 2. Sending the racy route to 1 would make the exit code a function of which side of a race the caller landed on, which is the disease the ENOENT rule exists to cure; it would just be the repository's race rather than the canvas file's. Exit 1 is also false advice here - it means re-read and re-decide, and a read never initialises the repository, so the re-read raises the same refusal forever. Condition (1) of todo 10329619223 is met the second way the condition allows: README.md section Exit codes states in its own words why a repository that vanished is 2 where a canvas file that vanished is 1. Checked on branch errno-on-repository-refusals before settling this: the docstring of _cannot_read_repository and README.md section Exit codes say the same thing, so neither had to be changed to make this settlement true.</text>
<text id="bv2j" v="1">Observed, before anything was changed. Both routes the todo names were run. EACCES (chmod 000 on .git) gives exit 2 and that is right. The vanished-repository route - .git removed between is_repository's os.stat and head_sha's rev-parse, simulated the way the parent todo's test does - gives exit 2 with 'cannot tell whether there are any commits in <dir>: looking at it was refused: [Errno 2] No such file or directory', an aftermath of 'what that repository holds is still unknown', a Canvas-About of 'errno 2 ENOENT', and a Canvas-Next whose repair is 'bin/canvas create <ledger-id> ...' - immediately under a Canvas-Exit that reads 'do not touch the canvas'. The exit code is arguable. Those last two lines are not: on ENOENT the tool can tell, it does know what the repository holds (nothing, because there is none), and a refusal that names a bin/canvas command as the repair cannot in the same breath say do not touch the canvas.</text>
<table id="uz6x" v="1">
<row id="s437" v="1">
<cell id="sm4b" v="1">Option</cell>
<cell id="zyrd" v="1">What it costs</cell>
</row>
<row id="fu7f" v="1">
<cell id="mkyr" v="1">A. Classify by errno, exactly as _cannot_read does: ENOENT returns the exit-1 refusal, every other errno stays a ToolProblem at exit 2.</cell>
<cell id="lgvs" v="2">The five call sites are not alike, and worse: the same fact already has an exit code. _not_a_repository (canvas/store.py:352) is what fires when the check itself finds no .git, and it is exit 2 - reproduced: 'state/canvas is not a git repository, so it has no sha to write against', Canvas-Exit 2, and its next action says 'a read never writes one'. Re-running the read does not fix it; only create does. So sending the racy ENOENT to exit 1 makes the exit code depend on which side of a race the caller landed - the exact disease _nothing_at's docstring says must not happen ('a race is the only difference between them, and the refusal a caller gets should not depend on which side of it they landed'). It would also send that caller to 're-read and re-decide' against a store where re-reading provably raises the same thing. Separately: is_repository's ENOENT never reaches this helper at all, because FileNotFoundError is caught above it and answered False.</cell>
</row>
<row id="pjt3" v="1">
<cell id="ymcz" v="1">B. Leave every errno at exit 2 and put the reason in README.md section Exit codes: a canvas file that is not there is a true statement about the store, while a canvas repository that is not there is the tool's own environment missing, and exit 2 is the code for that.</cell>
<cell id="smym" v="1">Two sibling helpers, sitting 170 lines apart, with visibly different rules for the same errno, and only a paragraph of README holding the difference in place. Nothing in the code enforces it, so the next person doing this refactor removes the special case again - which is how it came to be left out of the parent change in the first place. It also leaves the refusal saying 'what that repository holds is still unknown' at exit 2 in the one case where the errno said plainly that it holds nothing, because it is not there.</cell>
</row>
<row id="nyah" v="1">
<cell id="fbym" v="1">C. Split by call site: return exit 1 where the caller can act on the absence (is_repository) and exit 2 where it cannot (head_sha, the --base resolution, the ancestry check), by giving _cannot_read_repository a parameter that says which.</cell>
<cell id="rt82" v="1">This is classification by the guard the failure landed in, which is exactly the rule the parent change was made to remove. The same errno on the same directory would come back as two different exit codes depending on which command the caller happened to run, and a caller cannot see which guard it is inside. It also puts a sixth parameter on a helper with five call sites, and every one of them has to get it right for the rule to hold.</cell>
</row>
</table>
<text id="nf98" v="1">Where Case 1's code now stands, on branch errno-on-repository-refusals. _cannot_read_repository branches on errno.ENOENT and returns a new helper, _no_repository_at, which gives _not_a_repository's claim and _not_a_repository's repair in _not_a_repository's words - and at _not_a_repository's exit 2. So the option taken in code is B: a repository that vanished is a 2 where a canvas file that vanished is a 1, and README.md section Exit codes now says why in its own words. What the errno changed is what the tool says, not the code it exits with. EACCES is untouched and still says it cannot tell, because there the look really did fail. This node records what the code does; it does not close the question above it, which is still open and still carries all three options.</text>
</section>
<section id="y9hx" v="1" title="Open question 2 - may a Canvas-Next: line name a command that exits non-zero at all?">
<text id="mqxd" v="2">SETTLED, by the second writer, 2026-09-22: yes - a Canvas-Next: may name a command that exits non-zero, and one word says which one it may not. A command written after the word `run` is the repair: it is printed ready to run against real paths, running it is what makes the refused command work, and it exits 0. Everything else a next action names is either a diagnostic - `ls -ld`, `ls -l`, `df -h`, `ulimit -n`, there to show the state that produced the refusal - whose exit status is the answer and not a failure; or a form, a command with a <placeholder> in it that nobody runs as printed. So the rule the tool holds itself to is not 'every command a next action names succeeds' but 'every command a next action tells you to run succeeds'. The reason is not taste, it is what happened when I ran it. Option A - every command must exit 0 - is not implementable without gutting the surface: rendering all fifteen templates against a path that is genuinely gone and running every backticked command in each shows that four of them are not commands at all (`ulimit -n` is a shell builtin, `| cat | head -1` and `| head -1` are pipe fragments, `chown` is named bare with no operands) and that the ENOENT template's own repair exits 2 run verbatim, because it prints <ledger-id> where a ledger id goes. The remaining diagnostics exit 1 on precisely the condition their template exists for, because every way of looking at a path that is gone reports that it is gone by exiting non-zero. A would therefore either forbid a refusal about a missing path from telling a caller to look at it - the one thing a caller facing ENOENT most needs - or leave assertRepairsRun holding the hand-maintained allowlist that condition (3) was written to remove. B costs one marker, and the marker is syntactic rather than a list of command names, so a template that adds a repair nobody anticipated is covered the moment it is written.</text>
<table id="ehxj" v="1">
<row id="rysw" v="1">
<cell id="vp52" v="1">Option</cell>
<cell id="be5v" v="1">What it costs</cell>
</row>
<row id="vqpn" v="1">
<cell id="zksk" v="1">A. No. Every command a Canvas-Next: names must exit 0 when run against the state that produced the refusal. The `ls -ld` comes out of _OS_NEXT_ACTION[errno.ENOENT], and assertRepairsRun drops its chmod-only exemption and runs every command every template names.</cell>
<cell id="qdvs" v="1">A refusal can then only ever tell you to repair, never to look. The `ls -ld` on a missing path is not noise: its exit 1 and its 'No such file or directory' are the answer to which component of the path is gone, which is the thing a caller facing an ENOENT most wants to know and the thing bin/canvas cannot tell it. Dropping it means either finding a zero-exit way to ask the same question or accepting that the tool stops helping at the point the caller most needs it to.</cell>
</row>
<row id="yh66" v="1">
<cell id="vgke" v="2">CHOSEN. B. Yes, provided README.md section What a refusal prints says so and says how a caller tells the diagnostic from the repair - and provided the format carries that distinction somewhere a machine can read it, rather than leaving it to be inferred from the verb. As implemented: the distinction is the word `run` immediately in front of the command, README.md states it, and tests/test_store.py's assertRepairsRun reads it.</cell>
<cell id="lp37" v="2">What it cost, now that it has been paid rather than estimated. The estimate here was that telling the two apart means inventing a marker - a second trailer, a prefix, or a structure the line does not have - and that short of that assertRepairsRun keeps a hand-maintained list of commands it is allowed to run, which is the chmod-only exemption wearing a justification. Half right. A marker did have to be invented, but it cost one word in one template: _OS_NEXT_ACTION[errno.EACCES] is the only template in the whole table that names a command that is both runnable and a repair, so 'every existing template has to be classified against it' turned out to be one edit and not fifteen. And the marker is syntactic, not a list: assertRepairsRun runs whatever a next action marks with `run`, so a repair nobody anticipated is covered the moment somebody writes it. What is genuinely left over is that the marker is a word in prose rather than a trailer, so it is one careless sentence away from being dropped. The only thing holding it is the assertion in the other direction - every chmod a next action names must be marked - and that holds for chmod alone, because chmod is the one command in the surface that exists solely to make the refused command work. A second repair command that nobody marks would pass.</cell>
</row>
</table>
<text id="echr" v="2">For whoever takes Case 2, corrected - my first version of this node had the count wrong. Two things. (i) The reproduce command in the todo does not print what it says it does: `python3 bin/canvas read no-such-ledger 2>&1 | grep 'Canvas-Next:'` prints _nothing_at's next action, "create it with bin/canvas create no-such-ledger ...", and no ls at all, because that path never reaches refusal.os_next_action. (ii) _OS_NEXT_ACTION[errno.ENOENT] is reachable from far fewer places than grepping for os_next_action suggests. store.py has six calls to it, but four of them sit under an `except OSError` that a separate `except FileNotFoundError` above has already taken ENOENT away from - _no_canvas, the OPENCLAW_WORKSPACE stat, _write_and_commit's pre-write stat, and now _cannot_read_repository. Checked empirically, not by reading: spying on refusal.os_next_action and handing each helper a FileNotFoundError, exactly one errno 2 got through, from _cannot_write. So before Case 1's change the template had two reachable sites in store.py and now it has one, and that one is _cannot_write - which says in its own docstring that it is exit 2 for every errno, ENOENT included. Its Canvas-Next is the `ls -ld <state/canvas>` one. Case 2 is still live and still testable, including directly at the helper, the way test_an_unclassified_errno_still_refuses_in_the_shape already does.</text>
<text id="l32v" v="1">What running it showed, 2026-09-22, and two corrections to the todo's own text. I rendered every _OS_NEXT_ACTION template against a path that is genuinely gone and ran every backticked command each one names. Exit codes, verbatim: `ls -ld <gone>` 1; `ls -l <gone>` 1; `df -h <gone>` 1; `ulimit -n` 0; `chown` (named bare, no operands) 1; `bin/canvas create <ledger-id> --problem "<the problem>" --expected-value "<the expected value>"` 2, refused as 'not a usable ledger id'; `| cat | head -1` could not be run at all - [Errno 2] No such file or directory: '|'. Correction one: the todo says the repair in the ENOENT template 'succeeds and the parent todo's test runs it verbatim'. It does not succeed run verbatim, and the test does not run it. tests/test_store.py:4304 takes `bin/canvas create a-ledger-row` out of a different refusal - _nothing_at's, which fills the ledger id in - and then runs create with --problem P --expected-value V, substituting for the <the problem> placeholders by hand. Correction two: the ENOENT template says `ls -ld <path>` 'says which' directory on the way is missing. It does not. Checked both ways on the same machine: ls -ld prints one line and exits 1 whether the leaf is missing or a directory three levels up is, and the line names the path it was given either way. The diagnostic is still worth keeping - it distinguishes gone from unreadable, which is what a caller most needs - but it does not answer the question the template claims for it.</text>
<text id="ev4w" v="1">Where Case 2's code now stands, on branch errno-on-repository-refusals. canvas/refusal.py: the module docstring and the comment block over _OS_NEXT_ACTION state the rule and name the three kinds of thing a next action may hold - repair, diagnostic, form. _OS_NEXT_ACTION[errno.EACCES] is the only template in the table that names a command that is both runnable and a repair, and it now reads 'the repair is usually to run `chmod ...`' where it read '`chmod ...` is usually the repair'. No other template changed, because no other template names a runnable repair. README.md section What a refusal prints carries the rule in full, with the ls -ld exit 1 example and the bin/canvas create <ledger-id> form, and says which of the three a caller is looking at. tests/test_store.py assertRepairsRun no longer carries the chmod-only exemption: it runs every command a Canvas-Next: marks with `run`, whatever that command is, asserts it exits 0 and that it carries no <placeholder>, and asserts in the other direction that every chmod a next action names is marked as a repair - which is what stops the rule being satisfied by deleting the word. Demonstrated both ways rather than asserted. Against refusal.py exactly as it stood, the new assertion fails: 'named `chmod u+rx .../a-ledger-row.xml` without telling the caller to run it', 12 tests, FAILED (failures=1). With the change the same class is 12 tests OK and python3 -m unittest discover -s tests -t . is 263 tests OK. I also checked the assertion is not vacuous by pointing the marked repair at an invalid mode: it fails with '`chmod nosuchmode ...` is named as the repair and exited 1', so the command really is executed.</text>
<text id="g9ah" v="1">What the decision leaves open, named here so it is not mistaken for settled. (i) After this change _OS_NEXT_ACTION[errno.ENOENT] names no repair at all - a diagnostic and a form, and nothing marked `run`. That is allowed by the rule as settled, which says every command a next action tells you to run succeeds, not that every next action has a runnable repair to name. Whether a refusal ought to be required to name one is a different question and nothing in the repository asks it yet. (ii) The marker is a word in prose, not a trailer of its own, so it survives only as long as nobody rewrites the sentence around it. The single thing holding it is the converse assertion - every chmod a next action names must be marked - and that generalises to exactly one command, because chmod is the only one in the surface whose whole purpose is to make the refused command work. A second repair command that nobody marks would pass the suite. A Canvas-Repair: trailer beside Canvas-Next: would close that, at the cost of a sixth line in a block README describes as five. (iii) Both cases of todo 10329619223 are now answered on this branch, and the branch still does not descend from main - see node fdzu. A PR from it targets errors/actionable-refusal-surface, or waits for PR #8.</text>
<text id="qrpa" v="1">What the tool did about a second writer, recorded by the second writer. I arrived on this canvas holding e950b24a, the sha the first writer's handoff note names, and read it back before touching anything - it was still the head, so nothing had moved. After my own six edits I deliberately re-ran the edit to mqxd against e950b24a to see what the tool says to somebody who did not re-read. It took the hard branch: exit 1, 'refusing to write mqxd ... it moved in 1 commit(s) between --base e950b24a and 92361689, so this edit was decided against text that is no longer there. Nothing was applied and nothing was merged', then the intervening commit's subject, which is the whole --why of the edit that moved it, then git's own diff of the node from the old text to the new. Canvas-About: named the ledger id, the file, the --base I gave and the head; Canvas-Next: told me to read again, re-decide against the sha the read prints, and re-run with that --base. That is enough to act on without asking anybody: the reason the other writer changed it is in the output, so the re-decision can be made from the refusal itself rather than by reading the document again first. This node itself was inserted against the same stale e950b24a, which takes the soft branch instead - the write applies, and the same stdout that reports success carries Canvas-News and every intervening commit. What the tool does not carry either way is that somebody else is holding a base at all: read hands out a sha and says nothing about who wrote last or how old it is, so a second writer learns there was a first one from a Markdown file beside the canvas, not from the canvas.</text>
</section>
</canvas>
python3 bin/canvas read bc-10329619223-errno-decides-the-repository-refusals
exit: 0
Canvas-Base: fad921f83287af8aeb3996d672cc99db23808daf
<?xml version="1.0" encoding="UTF-8"?>
<canvas ledger="bc-10329619223-errno-decides-the-repository-refusals" schema="1">
<text id="bpx2" v="1">The parent change made every refusal's exit code, its repair and whatever it claims about the store derive from the errno the operating system actually returned, rather than from the guard the failure happened to land in - but one refusal helper and one next-action template were left outside that rule. canvas/store.py:582 _cannot_read_repository returns ToolProblem, exit 2, for every errno including ENOENT, where its sibling _cannot_read now returns exit 1 for ENOENT. canvas/refusal.py _OS_NEXT_ACTION[errno.ENOENT] says `ls -ld <path>` says which, and on a path that is genuinely gone that ls exits 1.</text>
<text id="bcr2" v="1">Every refusal helper in canvas/store.py that is handed an OSError chooses its exit code from the errno, _cannot_read_repository included - or README.md section Exit codes states, in its own words, why a repository that vanished is 2 where a canvas file that vanished is 1. A rule is settled and written down for whether a Canvas-Next: may name a command that exits non-zero. tests/test_store.py assertRepairsRun enforces whichever rule that settled. python3 -m unittest discover -s tests -t . passes from a clean tree, and the new behaviour fails against the code as it stands before the change - demonstrated, not asserted.</text>
<text id="fdzu" v="1">Branch base, and it is not main. Everything this todo cites exists only on origin/errors/actionable-refusal-surface, the branch of the still-open PR #8 for the parent todo 10326884685. On main there is no canvas/refusal.py at all, and canvas/store.py contains neither _cannot_read_repository nor _cannot_read - checked by git ls-tree and git show, both counts zero. So errno-on-repository-refusals is cut from origin/errors/actionable-refusal-surface at cd8d90e, and any half of this work branched from main names files that are not there. The suite on that branch is 263 tests, not main's 189.</text>
<section id="hp9p" v="1" title="Open question 1 - is a repository that vanished a 2 where a canvas file that vanished is a 1?">
<text id="t8zw" v="2">Settled, 2026-09-22, by the writer who opened this canvas and came back to it. A state/canvas repository that has vanished is exit 2, where a canvas file that has vanished is exit 1, and the errno decides what the refusal SAYS in both. Neither option as written on the table below is what the tree holds. Option A - classify _cannot_read_repository by errno the way _cannot_read is classified, and let ENOENT land on exit 1 - is rejected for its exit code. Option B - leave the helper unclassified for every errno and pay for it with a sentence in the README - is rejected for its silence in the code. What is in the tree is the half of each that is true: _cannot_read_repository branches on errno.ENOENT, and at ENOENT it returns _not_a_repository's claim, _not_a_repository's repair and _not_a_repository's words, at _not_a_repository's exit 2. The reason the code differs from the file case is that the two absences are not the same fact. A canvas that is not there is one missing file in a store that is otherwise intact, and the caller acts on it by creating that canvas - which is what exit 1 means. A state/canvas that is not there is the store itself, and that absence already has a code one syscall earlier: is_repository answers False for it and _not_a_repository refuses at 2. Sending the racy route to 1 would make the exit code a function of which side of a race the caller landed on, which is the disease the ENOENT rule exists to cure; it would just be the repository's race rather than the canvas file's. Exit 1 is also false advice here - it means re-read and re-decide, and a read never initialises the repository, so the re-read raises the same refusal forever. Condition (1) of todo 10329619223 is met the second way the condition allows: README.md section Exit codes states in its own words why a repository that vanished is 2 where a canvas file that vanished is 1. Checked on branch errno-on-repository-refusals before settling this: the docstring of _cannot_read_repository and README.md section Exit codes say the same thing, so neither had to be changed to make this settlement true.</text>
<text id="bv2j" v="1">Observed, before anything was changed. Both routes the todo names were run. EACCES (chmod 000 on .git) gives exit 2 and that is right. The vanished-repository route - .git removed between is_repository's os.stat and head_sha's rev-parse, simulated the way the parent todo's test does - gives exit 2 with 'cannot tell whether there are any commits in <dir>: looking at it was refused: [Errno 2] No such file or directory', an aftermath of 'what that repository holds is still unknown', a Canvas-About of 'errno 2 ENOENT', and a Canvas-Next whose repair is 'bin/canvas create <ledger-id> ...' - immediately under a Canvas-Exit that reads 'do not touch the canvas'. The exit code is arguable. Those last two lines are not: on ENOENT the tool can tell, it does know what the repository holds (nothing, because there is none), and a refusal that names a bin/canvas command as the repair cannot in the same breath say do not touch the canvas.</text>
<table id="uz6x" v="1">
<row id="s437" v="1">
<cell id="sm4b" v="1">Option</cell>
<cell id="zyrd" v="1">What it costs</cell>
</row>
<row id="fu7f" v="1">
<cell id="mkyr" v="1">A. Classify by errno, exactly as _cannot_read does: ENOENT returns the exit-1 refusal, every other errno stays a ToolProblem at exit 2.</cell>
<cell id="lgvs" v="2">The five call sites are not alike, and worse: the same fact already has an exit code. _not_a_repository (canvas/store.py:352) is what fires when the check itself finds no .git, and it is exit 2 - reproduced: 'state/canvas is not a git repository, so it has no sha to write against', Canvas-Exit 2, and its next action says 'a read never writes one'. Re-running the read does not fix it; only create does. So sending the racy ENOENT to exit 1 makes the exit code depend on which side of a race the caller landed - the exact disease _nothing_at's docstring says must not happen ('a race is the only difference between them, and the refusal a caller gets should not depend on which side of it they landed'). It would also send that caller to 're-read and re-decide' against a store where re-reading provably raises the same thing. Separately: is_repository's ENOENT never reaches this helper at all, because FileNotFoundError is caught above it and answered False.</cell>
</row>
<row id="pjt3" v="1">
<cell id="ymcz" v="1">B. Leave every errno at exit 2 and put the reason in README.md section Exit codes: a canvas file that is not there is a true statement about the store, while a canvas repository that is not there is the tool's own environment missing, and exit 2 is the code for that.</cell>
<cell id="smym" v="1">Two sibling helpers, sitting 170 lines apart, with visibly different rules for the same errno, and only a paragraph of README holding the difference in place. Nothing in the code enforces it, so the next person doing this refactor removes the special case again - which is how it came to be left out of the parent change in the first place. It also leaves the refusal saying 'what that repository holds is still unknown' at exit 2 in the one case where the errno said plainly that it holds nothing, because it is not there.</cell>
</row>
<row id="nyah" v="1">
<cell id="fbym" v="1">C. Split by call site: return exit 1 where the caller can act on the absence (is_repository) and exit 2 where it cannot (head_sha, the --base resolution, the ancestry check), by giving _cannot_read_repository a parameter that says which.</cell>
<cell id="rt82" v="1">This is classification by the guard the failure landed in, which is exactly the rule the parent change was made to remove. The same errno on the same directory would come back as two different exit codes depending on which command the caller happened to run, and a caller cannot see which guard it is inside. It also puts a sixth parameter on a helper with five call sites, and every one of them has to get it right for the rule to hold.</cell>
</row>
</table>
<text id="nf98" v="1">Where Case 1's code now stands, on branch errno-on-repository-refusals. _cannot_read_repository branches on errno.ENOENT and returns a new helper, _no_repository_at, which gives _not_a_repository's claim and _not_a_repository's repair in _not_a_repository's words - and at _not_a_repository's exit 2. So the option taken in code is B: a repository that vanished is a 2 where a canvas file that vanished is a 1, and README.md section Exit codes now says why in its own words. What the errno changed is what the tool says, not the code it exits with. EACCES is untouched and still says it cannot tell, because there the look really did fail. This node records what the code does; it does not close the question above it, which is still open and still carries all three options.</text>
</section>
<section id="y9hx" v="1" title="Open question 2 - may a Canvas-Next: line name a command that exits non-zero at all?">
<text id="mqxd" v="2">SETTLED, by the second writer, 2026-09-22: yes - a Canvas-Next: may name a command that exits non-zero, and one word says which one it may not. A command written after the word `run` is the repair: it is printed ready to run against real paths, running it is what makes the refused command work, and it exits 0. Everything else a next action names is either a diagnostic - `ls -ld`, `ls -l`, `df -h`, `ulimit -n`, there to show the state that produced the refusal - whose exit status is the answer and not a failure; or a form, a command with a <placeholder> in it that nobody runs as printed. So the rule the tool holds itself to is not 'every command a next action names succeeds' but 'every command a next action tells you to run succeeds'. The reason is not taste, it is what happened when I ran it. Option A - every command must exit 0 - is not implementable without gutting the surface: rendering all fifteen templates against a path that is genuinely gone and running every backticked command in each shows that four of them are not commands at all (`ulimit -n` is a shell builtin, `| cat | head -1` and `| head -1` are pipe fragments, `chown` is named bare with no operands) and that the ENOENT template's own repair exits 2 run verbatim, because it prints <ledger-id> where a ledger id goes. The remaining diagnostics exit 1 on precisely the condition their template exists for, because every way of looking at a path that is gone reports that it is gone by exiting non-zero. A would therefore either forbid a refusal about a missing path from telling a caller to look at it - the one thing a caller facing ENOENT most needs - or leave assertRepairsRun holding the hand-maintained allowlist that condition (3) was written to remove. B costs one marker, and the marker is syntactic rather than a list of command names, so a template that adds a repair nobody anticipated is covered the moment it is written.</text>
<table id="ehxj" v="1">
<row id="rysw" v="1">
<cell id="vp52" v="1">Option</cell>
<cell id="be5v" v="1">What it costs</cell>
</row>
<row id="vqpn" v="1">
<cell id="zksk" v="1">A. No. Every command a Canvas-Next: names must exit 0 when run against the state that produced the refusal. The `ls -ld` comes out of _OS_NEXT_ACTION[errno.ENOENT], and assertRepairsRun drops its chmod-only exemption and runs every command every template names.</cell>
<cell id="qdvs" v="1">A refusal can then only ever tell you to repair, never to look. The `ls -ld` on a missing path is not noise: its exit 1 and its 'No such file or directory' are the answer to which component of the path is gone, which is the thing a caller facing an ENOENT most wants to know and the thing bin/canvas cannot tell it. Dropping it means either finding a zero-exit way to ask the same question or accepting that the tool stops helping at the point the caller most needs it to.</cell>
</row>
<row id="yh66" v="1">
<cell id="vgke" v="2">CHOSEN. B. Yes, provided README.md section What a refusal prints says so and says how a caller tells the diagnostic from the repair - and provided the format carries that distinction somewhere a machine can read it, rather than leaving it to be inferred from the verb. As implemented: the distinction is the word `run` immediately in front of the command, README.md states it, and tests/test_store.py's assertRepairsRun reads it.</cell>
<cell id="lp37" v="2">What it cost, now that it has been paid rather than estimated. The estimate here was that telling the two apart means inventing a marker - a second trailer, a prefix, or a structure the line does not have - and that short of that assertRepairsRun keeps a hand-maintained list of commands it is allowed to run, which is the chmod-only exemption wearing a justification. Half right. A marker did have to be invented, but it cost one word in one template: _OS_NEXT_ACTION[errno.EACCES] is the only template in the whole table that names a command that is both runnable and a repair, so 'every existing template has to be classified against it' turned out to be one edit and not fifteen. And the marker is syntactic, not a list: assertRepairsRun runs whatever a next action marks with `run`, so a repair nobody anticipated is covered the moment somebody writes it. What is genuinely left over is that the marker is a word in prose rather than a trailer, so it is one careless sentence away from being dropped. The only thing holding it is the assertion in the other direction - every chmod a next action names must be marked - and that holds for chmod alone, because chmod is the one command in the surface that exists solely to make the refused command work. A second repair command that nobody marks would pass.</cell>
</row>
</table>
<text id="echr" v="2">For whoever takes Case 2, corrected - my first version of this node had the count wrong. Two things. (i) The reproduce command in the todo does not print what it says it does: `python3 bin/canvas read no-such-ledger 2>&1 | grep 'Canvas-Next:'` prints _nothing_at's next action, "create it with bin/canvas create no-such-ledger ...", and no ls at all, because that path never reaches refusal.os_next_action. (ii) _OS_NEXT_ACTION[errno.ENOENT] is reachable from far fewer places than grepping for os_next_action suggests. store.py has six calls to it, but four of them sit under an `except OSError` that a separate `except FileNotFoundError` above has already taken ENOENT away from - _no_canvas, the OPENCLAW_WORKSPACE stat, _write_and_commit's pre-write stat, and now _cannot_read_repository. Checked empirically, not by reading: spying on refusal.os_next_action and handing each helper a FileNotFoundError, exactly one errno 2 got through, from _cannot_write. So before Case 1's change the template had two reachable sites in store.py and now it has one, and that one is _cannot_write - which says in its own docstring that it is exit 2 for every errno, ENOENT included. Its Canvas-Next is the `ls -ld <state/canvas>` one. Case 2 is still live and still testable, including directly at the helper, the way test_an_unclassified_errno_still_refuses_in_the_shape already does.</text>
<text id="l32v" v="1">What running it showed, 2026-09-22, and two corrections to the todo's own text. I rendered every _OS_NEXT_ACTION template against a path that is genuinely gone and ran every backticked command each one names. Exit codes, verbatim: `ls -ld <gone>` 1; `ls -l <gone>` 1; `df -h <gone>` 1; `ulimit -n` 0; `chown` (named bare, no operands) 1; `bin/canvas create <ledger-id> --problem "<the problem>" --expected-value "<the expected value>"` 2, refused as 'not a usable ledger id'; `| cat | head -1` could not be run at all - [Errno 2] No such file or directory: '|'. Correction one: the todo says the repair in the ENOENT template 'succeeds and the parent todo's test runs it verbatim'. It does not succeed run verbatim, and the test does not run it. tests/test_store.py:4304 takes `bin/canvas create a-ledger-row` out of a different refusal - _nothing_at's, which fills the ledger id in - and then runs create with --problem P --expected-value V, substituting for the <the problem> placeholders by hand. Correction two: the ENOENT template says `ls -ld <path>` 'says which' directory on the way is missing. It does not. Checked both ways on the same machine: ls -ld prints one line and exits 1 whether the leaf is missing or a directory three levels up is, and the line names the path it was given either way. The diagnostic is still worth keeping - it distinguishes gone from unreadable, which is what a caller most needs - but it does not answer the question the template claims for it.</text>
<text id="ev4w" v="1">Where Case 2's code now stands, on branch errno-on-repository-refusals. canvas/refusal.py: the module docstring and the comment block over _OS_NEXT_ACTION state the rule and name the three kinds of thing a next action may hold - repair, diagnostic, form. _OS_NEXT_ACTION[errno.EACCES] is the only template in the table that names a command that is both runnable and a repair, and it now reads 'the repair is usually to run `chmod ...`' where it read '`chmod ...` is usually the repair'. No other template changed, because no other template names a runnable repair. README.md section What a refusal prints carries the rule in full, with the ls -ld exit 1 example and the bin/canvas create <ledger-id> form, and says which of the three a caller is looking at. tests/test_store.py assertRepairsRun no longer carries the chmod-only exemption: it runs every command a Canvas-Next: marks with `run`, whatever that command is, asserts it exits 0 and that it carries no <placeholder>, and asserts in the other direction that every chmod a next action names is marked as a repair - which is what stops the rule being satisfied by deleting the word. Demonstrated both ways rather than asserted. Against refusal.py exactly as it stood, the new assertion fails: 'named `chmod u+rx .../a-ledger-row.xml` without telling the caller to run it', 12 tests, FAILED (failures=1). With the change the same class is 12 tests OK and python3 -m unittest discover -s tests -t . is 263 tests OK. I also checked the assertion is not vacuous by pointing the marked repair at an invalid mode: it fails with '`chmod nosuchmode ...` is named as the repair and exited 1', so the command really is executed.</text>
<text id="g9ah" v="1">What the decision leaves open, named here so it is not mistaken for settled. (i) After this change _OS_NEXT_ACTION[errno.ENOENT] names no repair at all - a diagnostic and a form, and nothing marked `run`. That is allowed by the rule as settled, which says every command a next action tells you to run succeeds, not that every next action has a runnable repair to name. Whether a refusal ought to be required to name one is a different question and nothing in the repository asks it yet. (ii) The marker is a word in prose, not a trailer of its own, so it survives only as long as nobody rewrites the sentence around it. The single thing holding it is the converse assertion - every chmod a next action names must be marked - and that generalises to exactly one command, because chmod is the only one in the surface whose whole purpose is to make the refused command work. A second repair command that nobody marks would pass the suite. A Canvas-Repair: trailer beside Canvas-Next: would close that, at the cost of a sixth line in a block README describes as five. (iii) Both cases of todo 10329619223 are now answered on this branch, and the branch still does not descend from main - see node fdzu. A PR from it targets errors/actionable-refusal-surface, or waits for PR #8.</text>
<text id="qrpa" v="1">What the tool did about a second writer, recorded by the second writer. I arrived on this canvas holding e950b24a, the sha the first writer's handoff note names, and read it back before touching anything - it was still the head, so nothing had moved. After my own six edits I deliberately re-ran the edit to mqxd against e950b24a to see what the tool says to somebody who did not re-read. It took the hard branch: exit 1, 'refusing to write mqxd ... it moved in 1 commit(s) between --base e950b24a and 92361689, so this edit was decided against text that is no longer there. Nothing was applied and nothing was merged', then the intervening commit's subject, which is the whole --why of the edit that moved it, then git's own diff of the node from the old text to the new. Canvas-About: named the ledger id, the file, the --base I gave and the head; Canvas-Next: told me to read again, re-decide against the sha the read prints, and re-run with that --base. That is enough to act on without asking anybody: the reason the other writer changed it is in the output, so the re-decision can be made from the refusal itself rather than by reading the document again first. This node itself was inserted against the same stale e950b24a, which takes the soft branch instead - the write applies, and the same stdout that reports success carries Canvas-News and every intervening commit. What the tool does not carry either way is that somebody else is holding a base at all: read hands out a sha and says nothing about who wrote last or how old it is, so a second writer learns there was a first one from a Markdown file beside the canvas, not from the canvas.</text>
</section>
</canvas>
python3 bin/canvas replace bc-10329619223-errno-decides-the-repository-refusals t8zw --base fad921f83287af8aeb3996d672cc99db23808daf --text SETTLED, by the writer who opened this canvas, 2026-09-22: a state/canvas repository that has vanished is exit 2, where a canvas file that has vanished is exit 1 - and the errno decides what the refusal SAYS in both. Option B is the option taken. Option A is rejected on its exit code; option C is rejected because it classifies by the guard the failure landed in, which is the rule the parent change existed to remove. The reason B is right is that the two absences are not the same fact. A canvas that is not there is one missing file in a store that is otherwise intact, and the caller acts on it by creating that canvas - which is what exit 1 means here. A state/canvas that is not there is the store itself, and that absence already has a code one syscall earlier: is_repository answers False for it and _not_a_repository refuses at 2. Sending the racy route to 1 would make the exit code a function of which side of a race the caller landed on, which is the disease the ENOENT rule exists to cure; it would just be the repository's race rather than the canvas file's. Exit 1 is also false advice here - it means re-read and re-decide, and a read never initialises the repository, so the re-read raises the same refusal forever. One thing to read off the table rather than from this node: of the two costs option B's cost cell names, the second has been paid rather than accepted. The refusal no longer says it cannot tell and no longer says what that repository holds is still unknown at an ENOENT that said plainly it holds nothing, because _cannot_read_repository now branches on errno.ENOENT and hands back _not_a_repository's claim, repair and words at _not_a_repository's exit 2. The first cost stands: two sibling helpers 170 lines apart with different rules for the same errno, held apart by prose. Condition (1) of todo 10329619223 is met the second way it allows - README.md section Exit codes states in its own words why a repository that vanished is 2 where a canvas file that vanished is 1. Checked before settling: the docstring of _cannot_read_repository and README.md section Exit codes say the same thing, so neither had to change to make this settlement true. --why correcting my own resolution of this question, ninety seconds after writing it, and the correction is the finding. The version I committed said neither option as written is what the tree holds. That is wrong about B: B says leave every errno at exit 2 and put the reason in README.md section Exit codes, and that is exactly what the code does. I wrote it holding e950b24a, a base seven commits old, and the tool applied the edit and told me afterwards - the soft branch - so I did not read node nf98, which has said since the first half that the option taken in code is B, until my own contradiction of it was already committed. Replacing rather than appending, because a settled question that misdescribes its own settlement is the kind of thing a reader takes and acts on; the wrong sentence stays in this node's history where a reader who wants to know what I thought first can have it. The substance of the decision is unchanged - only the claim about which option it is.
exit: 0
Canvas-Node: t8zw
Canvas-Base: 619d585349186307536476f82443c8e72e156b39
python3 bin/canvas replace bc-10329619223-errno-decides-the-repository-refusals ymcz --base 619d585349186307536476f82443c8e72e156b39 --text CHOSEN. B. Leave every errno at exit 2 and put the reason in README.md section Exit codes: a canvas file that is not there is a true statement about the store, while a canvas repository that is not there is the tool's own environment missing, and exit 2 is the code for that. As implemented the reason README gives is narrower and better than the one written here when this option was drafted: not that the repository is the tool's environment, but that this same absence already has an exit code one syscall earlier - is_repository answers False and _not_a_repository refuses at 2 - so putting the racy route at 1 would make the code depend on which side of a race the caller landed on. --why marking on the table itself which option the decision above took, the way the second writer marked option B on the other table, because a reader who scrolls to a table of three live options should not have to reconstruct from the prose above it which one is dead. The tool has no way to mark a row chosen - a node carries no status - so the word goes in the cell's own text. Also correcting the option's own rationale against the one that survived contact: I drafted B saying the repository is the tool's environment, and what the README actually argues is the race, which is a stronger reason and a different one. Leaving the drafted rationale in place under a CHOSEN would publish a reason nobody relied on.
exit: 0
Canvas-Node: ymcz
Canvas-Base: 6be144ab299aae5059bbe326ad866af824d730c7
python3 bin/canvas replace bc-10329619223-errno-decides-the-repository-refusals smym --base 6be144ab299aae5059bbe326ad866af824d730c7 --text What it cost, now that it has been paid rather than estimated. Two costs were named here. The second is gone: this cell said B leaves the refusal saying what that repository holds is still unknown at exit 2 in the one case where the errno said plainly that it holds nothing. It does not, because taking B on the exit code did not mean taking it on the words - _cannot_read_repository branches on errno.ENOENT and returns _not_a_repository's claim, repair and words there, and only the code stays at 2. That distinction, between which code a refusal exits with and what it claims, is the thing this table did not have a column for and is most of what the answer turned out to be. The first cost stands and is real: two sibling helpers 170 lines apart now have visibly different rules for the same errno, and what holds them apart is a paragraph of README.md plus two docstrings. What guards it is not nothing - tests/test_store.py has the race and the plain check compared against one store, so the two routes to the same fact cannot drift apart without a failure - but nothing guards the asymmetry itself. The next person doing this refactor can still make both helpers alike and the suite will not stop them; it will only stop them making the two repository routes disagree with each other. --why replacing the estimate with what the option actually cost, the same way lgvs and lp37 were replaced once their options had been run rather than imagined. Half of this cell turned out to be a cost of a different option: it assumed exit code and wording travel together, so leaving the code at 2 meant keeping the sentence that contradicts the errno. They do not travel together, and separating them is what made B answerable at all. The other half is still true and I am keeping it as written rather than softening it, because it is the standing risk in this change and a cost cell that only records costs that were avoided is worth nothing to the next reader. Adding what does and does not guard it, since guessing at that is the first thing the next person will have to do.
exit: 0
Canvas-Node: smym
Canvas-Base: 153152b4ceda5bb33752a81fa3fdfe05ab96f588
python3 bin/canvas replace bc-10329619223-errno-decides-the-repository-refusals nf98 --base 153152b4ceda5bb33752a81fa3fdfe05ab96f588 --text Where Case 1's code stands, on branch errno-on-repository-refusals. _cannot_read_repository branches on errno.ENOENT and returns a new helper, _no_repository_at, which gives _not_a_repository's claim and _not_a_repository's repair in _not_a_repository's words - and at _not_a_repository's exit 2. So the option taken in code is B: a repository that vanished is a 2 where a canvas file that vanished is a 1, and README.md section Exit codes says why in its own words. What the errno changed is what the tool says, not the code it exits with. EACCES is untouched and still says it cannot tell, because there the look really did fail. The question above is no longer open: node t8zw carries the settlement and the reason, and the option cell ymcz is marked CHOSEN. This node is kept as the statement of where the code is, which is a different fact from the decision and is the one that goes stale first - if _cannot_read_repository is ever changed again, this is the node that becomes a lie, not t8zw. --why this node ended with the sentence that it does not close the question above it, which is still open and still carries all three options, and that is no longer true - t8zw is settled and ymcz is marked. A canvas whose nodes disagree about whether a question is open is worse than one that never said, because a reader trusts the nearest sentence. Keeping the rest of the node rather than folding it into the decision, because where the code stands and what was decided go stale at different rates: the decision is stable and this one is only true of the current tree, and saying which is which is the thing that stops the next writer updating the wrong one.
exit: 0
Canvas-Node: nf98
Canvas-Base: 3aebd7917ba910f24c7161fb896cd62d6ef3d2c7
python3 bin/canvas read bc-10329619223-errno-decides-the-repository-refusals
exit: 0
Canvas-Base: 3aebd7917ba910f24c7161fb896cd62d6ef3d2c7
<?xml version="1.0" encoding="UTF-8"?>
<canvas ledger="bc-10329619223-errno-decides-the-repository-refusals" schema="1">
<text id="bpx2" v="1">The parent change made every refusal's exit code, its repair and whatever it claims about the store derive from the errno the operating system actually returned, rather than from the guard the failure happened to land in - but one refusal helper and one next-action template were left outside that rule. canvas/store.py:582 _cannot_read_repository returns ToolProblem, exit 2, for every errno including ENOENT, where its sibling _cannot_read now returns exit 1 for ENOENT. canvas/refusal.py _OS_NEXT_ACTION[errno.ENOENT] says `ls -ld <path>` says which, and on a path that is genuinely gone that ls exits 1.</text>
<text id="bcr2" v="1">Every refusal helper in canvas/store.py that is handed an OSError chooses its exit code from the errno, _cannot_read_repository included - or README.md section Exit codes states, in its own words, why a repository that vanished is 2 where a canvas file that vanished is 1. A rule is settled and written down for whether a Canvas-Next: may name a command that exits non-zero. tests/test_store.py assertRepairsRun enforces whichever rule that settled. python3 -m unittest discover -s tests -t . passes from a clean tree, and the new behaviour fails against the code as it stands before the change - demonstrated, not asserted.</text>
<text id="fdzu" v="1">Branch base, and it is not main. Everything this todo cites exists only on origin/errors/actionable-refusal-surface, the branch of the still-open PR #8 for the parent todo 10326884685. On main there is no canvas/refusal.py at all, and canvas/store.py contains neither _cannot_read_repository nor _cannot_read - checked by git ls-tree and git show, both counts zero. So errno-on-repository-refusals is cut from origin/errors/actionable-refusal-surface at cd8d90e, and any half of this work branched from main names files that are not there. The suite on that branch is 263 tests, not main's 189.</text>
<section id="hp9p" v="1" title="Open question 1 - is a repository that vanished a 2 where a canvas file that vanished is a 1?">
<text id="t8zw" v="3">SETTLED, by the writer who opened this canvas, 2026-09-22: a state/canvas repository that has vanished is exit 2, where a canvas file that has vanished is exit 1 - and the errno decides what the refusal SAYS in both. Option B is the option taken. Option A is rejected on its exit code; option C is rejected because it classifies by the guard the failure landed in, which is the rule the parent change existed to remove. The reason B is right is that the two absences are not the same fact. A canvas that is not there is one missing file in a store that is otherwise intact, and the caller acts on it by creating that canvas - which is what exit 1 means here. A state/canvas that is not there is the store itself, and that absence already has a code one syscall earlier: is_repository answers False for it and _not_a_repository refuses at 2. Sending the racy route to 1 would make the exit code a function of which side of a race the caller landed on, which is the disease the ENOENT rule exists to cure; it would just be the repository's race rather than the canvas file's. Exit 1 is also false advice here - it means re-read and re-decide, and a read never initialises the repository, so the re-read raises the same refusal forever. One thing to read off the table rather than from this node: of the two costs option B's cost cell names, the second has been paid rather than accepted. The refusal no longer says it cannot tell and no longer says what that repository holds is still unknown at an ENOENT that said plainly it holds nothing, because _cannot_read_repository now branches on errno.ENOENT and hands back _not_a_repository's claim, repair and words at _not_a_repository's exit 2. The first cost stands: two sibling helpers 170 lines apart with different rules for the same errno, held apart by prose. Condition (1) of todo 10329619223 is met the second way it allows - README.md section Exit codes states in its own words why a repository that vanished is 2 where a canvas file that vanished is 1. Checked before settling: the docstring of _cannot_read_repository and README.md section Exit codes say the same thing, so neither had to change to make this settlement true.</text>
<text id="bv2j" v="1">Observed, before anything was changed. Both routes the todo names were run. EACCES (chmod 000 on .git) gives exit 2 and that is right. The vanished-repository route - .git removed between is_repository's os.stat and head_sha's rev-parse, simulated the way the parent todo's test does - gives exit 2 with 'cannot tell whether there are any commits in <dir>: looking at it was refused: [Errno 2] No such file or directory', an aftermath of 'what that repository holds is still unknown', a Canvas-About of 'errno 2 ENOENT', and a Canvas-Next whose repair is 'bin/canvas create <ledger-id> ...' - immediately under a Canvas-Exit that reads 'do not touch the canvas'. The exit code is arguable. Those last two lines are not: on ENOENT the tool can tell, it does know what the repository holds (nothing, because there is none), and a refusal that names a bin/canvas command as the repair cannot in the same breath say do not touch the canvas.</text>
<table id="uz6x" v="1">
<row id="s437" v="1">
<cell id="sm4b" v="1">Option</cell>
<cell id="zyrd" v="1">What it costs</cell>
</row>
<row id="fu7f" v="1">
<cell id="mkyr" v="1">A. Classify by errno, exactly as _cannot_read does: ENOENT returns the exit-1 refusal, every other errno stays a ToolProblem at exit 2.</cell>
<cell id="lgvs" v="2">The five call sites are not alike, and worse: the same fact already has an exit code. _not_a_repository (canvas/store.py:352) is what fires when the check itself finds no .git, and it is exit 2 - reproduced: 'state/canvas is not a git repository, so it has no sha to write against', Canvas-Exit 2, and its next action says 'a read never writes one'. Re-running the read does not fix it; only create does. So sending the racy ENOENT to exit 1 makes the exit code depend on which side of a race the caller landed - the exact disease _nothing_at's docstring says must not happen ('a race is the only difference between them, and the refusal a caller gets should not depend on which side of it they landed'). It would also send that caller to 're-read and re-decide' against a store where re-reading provably raises the same thing. Separately: is_repository's ENOENT never reaches this helper at all, because FileNotFoundError is caught above it and answered False.</cell>
</row>
<row id="pjt3" v="1">
<cell id="ymcz" v="2">CHOSEN. B. Leave every errno at exit 2 and put the reason in README.md section Exit codes: a canvas file that is not there is a true statement about the store, while a canvas repository that is not there is the tool's own environment missing, and exit 2 is the code for that. As implemented the reason README gives is narrower and better than the one written here when this option was drafted: not that the repository is the tool's environment, but that this same absence already has an exit code one syscall earlier - is_repository answers False and _not_a_repository refuses at 2 - so putting the racy route at 1 would make the code depend on which side of a race the caller landed on.</cell>
<cell id="smym" v="2">What it cost, now that it has been paid rather than estimated. Two costs were named here. The second is gone: this cell said B leaves the refusal saying what that repository holds is still unknown at exit 2 in the one case where the errno said plainly that it holds nothing. It does not, because taking B on the exit code did not mean taking it on the words - _cannot_read_repository branches on errno.ENOENT and returns _not_a_repository's claim, repair and words there, and only the code stays at 2. That distinction, between which code a refusal exits with and what it claims, is the thing this table did not have a column for and is most of what the answer turned out to be. The first cost stands and is real: two sibling helpers 170 lines apart now have visibly different rules for the same errno, and what holds them apart is a paragraph of README.md plus two docstrings. What guards it is not nothing - tests/test_store.py has the race and the plain check compared against one store, so the two routes to the same fact cannot drift apart without a failure - but nothing guards the asymmetry itself. The next person doing this refactor can still make both helpers alike and the suite will not stop them; it will only stop them making the two repository routes disagree with each other.</cell>
</row>
<row id="nyah" v="1">
<cell id="fbym" v="1">C. Split by call site: return exit 1 where the caller can act on the absence (is_repository) and exit 2 where it cannot (head_sha, the --base resolution, the ancestry check), by giving _cannot_read_repository a parameter that says which.</cell>
<cell id="rt82" v="1">This is classification by the guard the failure landed in, which is exactly the rule the parent change was made to remove. The same errno on the same directory would come back as two different exit codes depending on which command the caller happened to run, and a caller cannot see which guard it is inside. It also puts a sixth parameter on a helper with five call sites, and every one of them has to get it right for the rule to hold.</cell>
</row>
</table>
<text id="nf98" v="2">Where Case 1's code stands, on branch errno-on-repository-refusals. _cannot_read_repository branches on errno.ENOENT and returns a new helper, _no_repository_at, which gives _not_a_repository's claim and _not_a_repository's repair in _not_a_repository's words - and at _not_a_repository's exit 2. So the option taken in code is B: a repository that vanished is a 2 where a canvas file that vanished is a 1, and README.md section Exit codes says why in its own words. What the errno changed is what the tool says, not the code it exits with. EACCES is untouched and still says it cannot tell, because there the look really did fail. The question above is no longer open: node t8zw carries the settlement and the reason, and the option cell ymcz is marked CHOSEN. This node is kept as the statement of where the code is, which is a different fact from the decision and is the one that goes stale first - if _cannot_read_repository is ever changed again, this is the node that becomes a lie, not t8zw.</text>
</section>
<section id="y9hx" v="1" title="Open question 2 - may a Canvas-Next: line name a command that exits non-zero at all?">
<text id="mqxd" v="2">SETTLED, by the second writer, 2026-09-22: yes - a Canvas-Next: may name a command that exits non-zero, and one word says which one it may not. A command written after the word `run` is the repair: it is printed ready to run against real paths, running it is what makes the refused command work, and it exits 0. Everything else a next action names is either a diagnostic - `ls -ld`, `ls -l`, `df -h`, `ulimit -n`, there to show the state that produced the refusal - whose exit status is the answer and not a failure; or a form, a command with a <placeholder> in it that nobody runs as printed. So the rule the tool holds itself to is not 'every command a next action names succeeds' but 'every command a next action tells you to run succeeds'. The reason is not taste, it is what happened when I ran it. Option A - every command must exit 0 - is not implementable without gutting the surface: rendering all fifteen templates against a path that is genuinely gone and running every backticked command in each shows that four of them are not commands at all (`ulimit -n` is a shell builtin, `| cat | head -1` and `| head -1` are pipe fragments, `chown` is named bare with no operands) and that the ENOENT template's own repair exits 2 run verbatim, because it prints <ledger-id> where a ledger id goes. The remaining diagnostics exit 1 on precisely the condition their template exists for, because every way of looking at a path that is gone reports that it is gone by exiting non-zero. A would therefore either forbid a refusal about a missing path from telling a caller to look at it - the one thing a caller facing ENOENT most needs - or leave assertRepairsRun holding the hand-maintained allowlist that condition (3) was written to remove. B costs one marker, and the marker is syntactic rather than a list of command names, so a template that adds a repair nobody anticipated is covered the moment it is written.</text>
<table id="ehxj" v="1">
<row id="rysw" v="1">
<cell id="vp52" v="1">Option</cell>
<cell id="be5v" v="1">What it costs</cell>
</row>
<row id="vqpn" v="1">
<cell id="zksk" v="1">A. No. Every command a Canvas-Next: names must exit 0 when run against the state that produced the refusal. The `ls -ld` comes out of _OS_NEXT_ACTION[errno.ENOENT], and assertRepairsRun drops its chmod-only exemption and runs every command every template names.</cell>
<cell id="qdvs" v="1">A refusal can then only ever tell you to repair, never to look. The `ls -ld` on a missing path is not noise: its exit 1 and its 'No such file or directory' are the answer to which component of the path is gone, which is the thing a caller facing an ENOENT most wants to know and the thing bin/canvas cannot tell it. Dropping it means either finding a zero-exit way to ask the same question or accepting that the tool stops helping at the point the caller most needs it to.</cell>
</row>
<row id="yh66" v="1">
<cell id="vgke" v="2">CHOSEN. B. Yes, provided README.md section What a refusal prints says so and says how a caller tells the diagnostic from the repair - and provided the format carries that distinction somewhere a machine can read it, rather than leaving it to be inferred from the verb. As implemented: the distinction is the word `run` immediately in front of the command, README.md states it, and tests/test_store.py's assertRepairsRun reads it.</cell>
<cell id="lp37" v="2">What it cost, now that it has been paid rather than estimated. The estimate here was that telling the two apart means inventing a marker - a second trailer, a prefix, or a structure the line does not have - and that short of that assertRepairsRun keeps a hand-maintained list of commands it is allowed to run, which is the chmod-only exemption wearing a justification. Half right. A marker did have to be invented, but it cost one word in one template: _OS_NEXT_ACTION[errno.EACCES] is the only template in the whole table that names a command that is both runnable and a repair, so 'every existing template has to be classified against it' turned out to be one edit and not fifteen. And the marker is syntactic, not a list: assertRepairsRun runs whatever a next action marks with `run`, so a repair nobody anticipated is covered the moment somebody writes it. What is genuinely left over is that the marker is a word in prose rather than a trailer, so it is one careless sentence away from being dropped. The only thing holding it is the assertion in the other direction - every chmod a next action names must be marked - and that holds for chmod alone, because chmod is the one command in the surface that exists solely to make the refused command work. A second repair command that nobody marks would pass.</cell>
</row>
</table>
<text id="echr" v="2">For whoever takes Case 2, corrected - my first version of this node had the count wrong. Two things. (i) The reproduce command in the todo does not print what it says it does: `python3 bin/canvas read no-such-ledger 2>&1 | grep 'Canvas-Next:'` prints _nothing_at's next action, "create it with bin/canvas create no-such-ledger ...", and no ls at all, because that path never reaches refusal.os_next_action. (ii) _OS_NEXT_ACTION[errno.ENOENT] is reachable from far fewer places than grepping for os_next_action suggests. store.py has six calls to it, but four of them sit under an `except OSError` that a separate `except FileNotFoundError` above has already taken ENOENT away from - _no_canvas, the OPENCLAW_WORKSPACE stat, _write_and_commit's pre-write stat, and now _cannot_read_repository. Checked empirically, not by reading: spying on refusal.os_next_action and handing each helper a FileNotFoundError, exactly one errno 2 got through, from _cannot_write. So before Case 1's change the template had two reachable sites in store.py and now it has one, and that one is _cannot_write - which says in its own docstring that it is exit 2 for every errno, ENOENT included. Its Canvas-Next is the `ls -ld <state/canvas>` one. Case 2 is still live and still testable, including directly at the helper, the way test_an_unclassified_errno_still_refuses_in_the_shape already does.</text>
<text id="l32v" v="1">What running it showed, 2026-09-22, and two corrections to the todo's own text. I rendered every _OS_NEXT_ACTION template against a path that is genuinely gone and ran every backticked command each one names. Exit codes, verbatim: `ls -ld <gone>` 1; `ls -l <gone>` 1; `df -h <gone>` 1; `ulimit -n` 0; `chown` (named bare, no operands) 1; `bin/canvas create <ledger-id> --problem "<the problem>" --expected-value "<the expected value>"` 2, refused as 'not a usable ledger id'; `| cat | head -1` could not be run at all - [Errno 2] No such file or directory: '|'. Correction one: the todo says the repair in the ENOENT template 'succeeds and the parent todo's test runs it verbatim'. It does not succeed run verbatim, and the test does not run it. tests/test_store.py:4304 takes `bin/canvas create a-ledger-row` out of a different refusal - _nothing_at's, which fills the ledger id in - and then runs create with --problem P --expected-value V, substituting for the <the problem> placeholders by hand. Correction two: the ENOENT template says `ls -ld <path>` 'says which' directory on the way is missing. It does not. Checked both ways on the same machine: ls -ld prints one line and exits 1 whether the leaf is missing or a directory three levels up is, and the line names the path it was given either way. The diagnostic is still worth keeping - it distinguishes gone from unreadable, which is what a caller most needs - but it does not answer the question the template claims for it.</text>
<text id="ev4w" v="1">Where Case 2's code now stands, on branch errno-on-repository-refusals. canvas/refusal.py: the module docstring and the comment block over _OS_NEXT_ACTION state the rule and name the three kinds of thing a next action may hold - repair, diagnostic, form. _OS_NEXT_ACTION[errno.EACCES] is the only template in the table that names a command that is both runnable and a repair, and it now reads 'the repair is usually to run `chmod ...`' where it read '`chmod ...` is usually the repair'. No other template changed, because no other template names a runnable repair. README.md section What a refusal prints carries the rule in full, with the ls -ld exit 1 example and the bin/canvas create <ledger-id> form, and says which of the three a caller is looking at. tests/test_store.py assertRepairsRun no longer carries the chmod-only exemption: it runs every command a Canvas-Next: marks with `run`, whatever that command is, asserts it exits 0 and that it carries no <placeholder>, and asserts in the other direction that every chmod a next action names is marked as a repair - which is what stops the rule being satisfied by deleting the word. Demonstrated both ways rather than asserted. Against refusal.py exactly as it stood, the new assertion fails: 'named `chmod u+rx .../a-ledger-row.xml` without telling the caller to run it', 12 tests, FAILED (failures=1). With the change the same class is 12 tests OK and python3 -m unittest discover -s tests -t . is 263 tests OK. I also checked the assertion is not vacuous by pointing the marked repair at an invalid mode: it fails with '`chmod nosuchmode ...` is named as the repair and exited 1', so the command really is executed.</text>
<text id="g9ah" v="1">What the decision leaves open, named here so it is not mistaken for settled. (i) After this change _OS_NEXT_ACTION[errno.ENOENT] names no repair at all - a diagnostic and a form, and nothing marked `run`. That is allowed by the rule as settled, which says every command a next action tells you to run succeeds, not that every next action has a runnable repair to name. Whether a refusal ought to be required to name one is a different question and nothing in the repository asks it yet. (ii) The marker is a word in prose, not a trailer of its own, so it survives only as long as nobody rewrites the sentence around it. The single thing holding it is the converse assertion - every chmod a next action names must be marked - and that generalises to exactly one command, because chmod is the only one in the surface whose whole purpose is to make the refused command work. A second repair command that nobody marks would pass the suite. A Canvas-Repair: trailer beside Canvas-Next: would close that, at the cost of a sixth line in a block README describes as five. (iii) Both cases of todo 10329619223 are now answered on this branch, and the branch still does not descend from main - see node fdzu. A PR from it targets errors/actionable-refusal-surface, or waits for PR #8.</text>
<text id="qrpa" v="1">What the tool did about a second writer, recorded by the second writer. I arrived on this canvas holding e950b24a, the sha the first writer's handoff note names, and read it back before touching anything - it was still the head, so nothing had moved. After my own six edits I deliberately re-ran the edit to mqxd against e950b24a to see what the tool says to somebody who did not re-read. It took the hard branch: exit 1, 'refusing to write mqxd ... it moved in 1 commit(s) between --base e950b24a and 92361689, so this edit was decided against text that is no longer there. Nothing was applied and nothing was merged', then the intervening commit's subject, which is the whole --why of the edit that moved it, then git's own diff of the node from the old text to the new. Canvas-About: named the ledger id, the file, the --base I gave and the head; Canvas-Next: told me to read again, re-decide against the sha the read prints, and re-run with that --base. That is enough to act on without asking anybody: the reason the other writer changed it is in the output, so the re-decision can be made from the refusal itself rather than by reading the document again first. This node itself was inserted against the same stale e950b24a, which takes the soft branch instead - the write applies, and the same stdout that reports success carries Canvas-News and every intervening commit. What the tool does not carry either way is that somebody else is holding a base at all: read hands out a sha and says nothing about who wrote last or how old it is, so a second writer learns there was a first one from a Markdown file beside the canvas, not from the canvas.</text>
</section>
</canvas>
python3 bin/canvas insert bc-10329619223-errno-decides-the-repository-refusals --into root --base 3aebd7917ba910f24c7161fb896cd62d6ef3d2c7 --type section --title Outcome - what this task changed, what it decided, and what is now true that was not --why the task is finished and the canvas has to say so. engineering-spec.md section Lifecycle says a canvas is frozen at done and that the done gate's What/Why/Evidence/Verification/Links artifact is a projection of the canvas - so if the outcome is not in here, the projection has nothing to project from and the canvas ends as a record of two arguments with no ending. Putting it in its own section at the foot rather than threading it through the two question sections, because those sections are the reasoning and this is the result, and a reader arriving cold wants the result first and the reasoning only if they doubt it.
exit: 0
Canvas-Node: trhx
Canvas-Base: a846cb7b62a780a881ae39e8fdb5847761287347
python3 bin/canvas insert bc-10329619223-errno-decides-the-repository-refusals --into trhx --base a846cb7b62a780a881ae39e8fdb5847761287347 --type text --text What changed. Branch errno-on-repository-refusals, cut from origin/errors/actionable-refusal-surface at cd8d90e and NOT from main - see node fdzu. Two commits. (1) a948431, refusals: let ENOENT say the repository is not there, at the code the check already gives - canvas/store.py +60, README.md +19, tests/test_store.py +131. It adds _no_repository_at beside _not_a_repository, makes _cannot_read_repository branch on errno.ENOENT into it, states the 1-versus-2 asymmetry in README.md section Exit codes as a standing rule rather than a note about one function, and adds two tests: one that runs the race and the plain check against one store and requires them to say the same thing, one that pins EACCES so the ENOENT answer cannot be got by deleting the honest sentence for every errno. (2) 8326431, refusals: settle that a next action may look as well as repair, and mark which is which - README.md +38, canvas/refusal.py +36-1, tests/test_store.py +124-31. It states the run-marks-the-repair rule in canvas/refusal.py's docstring and over _OS_NEXT_ACTION, states it in full in README.md section What a refusal prints, changes the one template in the table that names a runnable repair so that it says the repair is usually to run chmod, and rewrites assertRepairsRun to run every command marked run, to reject a marked repair carrying a placeholder, and to require in the other direction that every chmod a next action names is marked. Net across both: README.md +57, canvas/refusal.py +36-1, canvas/store.py +60, tests/test_store.py +255-31. --why so that a reader can tell what this task did to the tree without being handed a diff, and so that the two commits are attributable - the first is Case 1 and the second is Case 2, and they were made by different writers on the same branch. Naming the branch point in the same breath as the branch, because it is the single fact most likely to waste somebody's afternoon: this branch does not descend from main and a PR from it does not target main.
exit: 0
Canvas-Node: aqr3
Canvas-Base: b62b42858a32e0885fd909f046be22da3bd8456f
python3 bin/canvas insert bc-10329619223-errno-decides-the-repository-refusals --into trhx --base b62b42858a32e0885fd909f046be22da3bd8456f --type text --text What is now true that was not. (1) The exit code of a refusal about the state/canvas repository no longer depends on which side of a race the caller landed on. Before this task, is_repository finding no .git refused at 2 saying the repository is not there, and the same .git vanishing one syscall later refused at 2 saying it could not tell whether there are any commits in it - same code, opposite claims, and the second one contradicted the errno 2 ENOENT printed three lines under it. Now both say the repository is not there, both name bin/canvas create as the repair, and the test that compares the two routes against one store is what keeps them from drifting apart again. (2) A caller can tell, from one word and without knowing which commands this tool uses, which of the things a Canvas-Next: names is the one that is claimed to work. Before, the claim was carried by a convention held in one test's regex - chmod is a repair, ls and df are not - and the surface had no way to admit a repair the regex had not been written for. Now the marker is in the printed line itself, the README explains it to the caller who is reading the refusal rather than the code, and assertRepairsRun executes whatever is marked. (3) tests/test_store.py no longer carries an exemption that excused a class of command from the rule the class exists to enforce. The exemption is replaced by a two-directional check, so the rule can be escaped neither by naming an unrunnable repair nor by dropping the word that marks one. (4) Two claims in todo 10329619223's own description are now known to be false and are recorded in this canvas rather than left for the next reader to rediscover: node echr on its Case 2 reproduce command, node l32v on the repair it says runs verbatim and on what ls -ld actually tells you. --why this is the part of an outcome that is hardest to reconstruct later and the part most worth having. What changed is in the diff; what is now TRUE that was not is nowhere except here, and it is the thing somebody reviewing this in three weeks actually wants - they will want to know whether the change bought anything, not which lines moved. Writing each one as a before-and-after pair rather than as a claim, because a benefit stated without the state it replaced is unfalsifiable and this canvas is supposed to be checkable.
exit: 0
Canvas-Node: y44g
Canvas-Base: b2a23632fa9ae38b4b050a0a87a808d251f77c59
python3 bin/canvas insert bc-10329619223-errno-decides-the-repository-refusals --into trhx --base b2a23632fa9ae38b4b050a0a87a808d251f77c59 --type text --text Verification - the four Done when conditions of todo 10329619223, each run rather than asserted, 2026-09-22, at HEAD 8326431 from a clean tree. (1) Met the second way the condition allows: README.md line 567 begins the paragraph that states why a canvas file that vanished is 1 and the state/canvas repository that vanished is 2. Run both ways on one store: chmod 000 on state/canvas/.git gives cannot tell whether there are any commits in it, errno 13 EACCES, exit 2; the .git removed between is_repository's os.stat and the rev-parse after it gives is not a git repository - .git is not there, so there is no answer here to whether there are any commits in it, errno 2 ENOENT, exit 2, with make the first canvas with bin/canvas create as its next action. (2) Met: the rule is that a Canvas-Next: MAY name a command that exits non-zero, and README.md line 658 states it and states how a caller tells the diagnostic from the repair - the word run. canvas/refusal.py carries it at line 36 and line 145. (3) Met: assertRepairsRun's chmod-only findall is gone; it now runs every command the REPAIR pattern marks, rejects a marked repair carrying a placeholder, and asserts every chmod a next action names is marked. (4) Met and demonstrated in both directions. With canvas/ checked out at cd8d90e and tests/ left at HEAD - the new tests against the code as it stood - python3 -m unittest -v tests.test_store.EveryRefusalIsTrueAndItsNextActionRuns gives Ran 12 tests, FAILED (failures=2), one failure per case: Case 1 at assertNotIn cannot tell, Case 2 at named chmod u+rx ... without telling the caller to run it. Restored to HEAD the same twelve are OK, and python3 -m unittest discover -s tests -t . from the clean tree is Ran 263 tests in 92.483s, OK, exit 0, with the tree still clean afterwards. The full transcript of every one of these commands and its output is in .orchestrator-artifacts/done-when-verification.txt. --why condition (4) says demonstrated, not asserted, and a canvas that only claims the conditions hold is exactly the assertion it forbids. Writing the observed strings - the message, the errno, the exit code, the failure count and where each failure landed - rather than the word passed, because a reader who doubts this node has to be able to re-run it and compare, and a number they can compare is the only part of a verification claim that is worth anything. Naming the file the full output is in rather than pasting it, because the canvas is supposed to stay readable in a minute and the specs are explicit that it is not a transcript.
exit: 0
Canvas-Node: fxp8
Canvas-Base: 2ef45c2155c61c60ed37148d61efd80c6c906236
python3 bin/canvas insert bc-10329619223-errno-decides-the-repository-refusals --into trhx --base 2ef45c2155c61c60ed37148d61efd80c6c906236 --type link --href https://app.basecamp.com/3934852/buckets/48039419/todos/10329619223 --text Todo 10329619223 - the task this canvas is for, and the authority on its four Done when conditions. 0 comments, so the description stands unmodified. --why the canvas holds what we think about a task and has said nothing so far about where the task itself lives. A reader who wants to check condition (3) against its own wording has to be able to get to the wording, and until now the only route was a Basecamp id typed inside a node's prose. link is the one element in the vocabulary that carries an href, so this is the one place in the document a reader can follow rather than retype.
exit: 0
Canvas-Node: mqu7
Canvas-Base: 605185ad5ac89ff5e59fc46e8564fecb611de0dd
python3 bin/canvas insert bc-10329619223-errno-decides-the-repository-refusals --into trhx --base 605185ad5ac89ff5e59fc46e8564fecb611de0dd --type link --href https://github.com/malkovro/canvas/pull/8 --text PR #8, errors/actionable-refusal-surface - the parent change, still open. Branch errno-on-repository-refusals sits on top of it, so a PR from this work targets that branch or waits for #8 to merge. --why the one dependency this task's branch has on something outside itself, and the one that decides what a reviewer can do with it. Saying it as a link rather than as another sentence in a text node because it is the thing a reader will want to click to find out whether the dependency has cleared, and because that fact goes stale on its own schedule - #8 merges or it does not, with nothing in this task changing.
exit: 0
Canvas-Node: qrfs
Canvas-Base: d3b508374daed3e3f474d5267aa092c8ca892e40
python3 bin/canvas --help
exit: 0
usage: canvas [-h] {create,read,history,replace,insert,remove,move} ...
The canvas store: one XML file per ledger row, git-backed.
positional arguments:
{create,read,history,replace,insert,remove,move}
create make the canvas for a ledger row, with its first nodes
read print the canvas and the sha to write against
history print one node's edits, oldest first, with the reason
for each
replace replace one node, possibly with a node of a different
type
insert add one node at a named position
remove take one node out of the document
move change one node's position and nothing else
options:
-h, --help show this help message and exit
python3 bin/canvas insert bc-10329619223-errno-decides-the-repository-refusals --into trhx --base d3b508374daed3e3f474d5267aa092c8ca892e40 --type text --text This canvas is at its end, and the last edit is this one. Both open questions are settled - t8zw carries Case 1's decision and its chosen option is marked on uz6x at ymcz; mqxd carries Case 2's decision and its chosen option is marked on ehxj at vgke. Both options tables are kept rather than collapsed, which engineering-spec.md section What to copy says is right: a superseded options table is not deleted from anywhere, it is out of the current document or marked and one command away in the history, and the canvas stays small because resolution is routine and not because anybody prunes. All four Done when conditions are verified at fxp8. What remains open is named and is not this task's: node g9ah lists the three loose ends Case 2's decision leaves, and the largest of them - the run marker is a word in prose rather than a trailer, held up by a converse check that generalises to exactly one command - is the thing to raise next. One honest caveat about the word end. engineering-spec.md section Lifecycle says a canvas is frozen at done and is read-only history after it, and bin/canvas has no verb that freezes one: the seven subcommands are create, read, history, replace, insert, remove and move, and the four writing verbs go on working on this document forever. So this node is the nearest thing the tool allows - a statement, in an ordinary node, that the document is finished - and anybody with the ledger id can still write to it tomorrow. The freeze the spec describes is a property of the ledger row's state, not of the canvas, and nothing in the store enforces it. --why the last edit of a task's canvas should say that it is the last edit, because otherwise a reader cannot tell a finished canvas from an abandoned one - both look like a document that stopped. Saying where the open questions ended and which table holds the mark, so that a reader arriving at the foot can navigate back up rather than reading everything. And recording the caveat rather than writing a sentence that sounds like a freeze: the spec says frozen at done, the tool has no verb for it, and claiming this canvas is closed when any of four verbs will still change it would be the canvas asserting something about the store that is not true - which is the exact defect the task this canvas is about existed to fix. Recording the inconvenience is what the exercise asked for; expressing the nearest thing the tool does allow is the other half of it.
exit: 0
Canvas-Node: gjxb
Canvas-Base: 02de26b71893d1d33d1559cd0fd9bcfcaff84652
python3 bin/canvas read bc-10329619223-errno-decides-the-repository-refusals
exit: 0
Canvas-Base: 02de26b71893d1d33d1559cd0fd9bcfcaff84652
<?xml version="1.0" encoding="UTF-8"?>
<canvas ledger="bc-10329619223-errno-decides-the-repository-refusals" schema="1">
<text id="bpx2" v="1">The parent change made every refusal's exit code, its repair and whatever it claims about the store derive from the errno the operating system actually returned, rather than from the guard the failure happened to land in - but one refusal helper and one next-action template were left outside that rule. canvas/store.py:582 _cannot_read_repository returns ToolProblem, exit 2, for every errno including ENOENT, where its sibling _cannot_read now returns exit 1 for ENOENT. canvas/refusal.py _OS_NEXT_ACTION[errno.ENOENT] says `ls -ld <path>` says which, and on a path that is genuinely gone that ls exits 1.</text>
<text id="bcr2" v="1">Every refusal helper in canvas/store.py that is handed an OSError chooses its exit code from the errno, _cannot_read_repository included - or README.md section Exit codes states, in its own words, why a repository that vanished is 2 where a canvas file that vanished is 1. A rule is settled and written down for whether a Canvas-Next: may name a command that exits non-zero. tests/test_store.py assertRepairsRun enforces whichever rule that settled. python3 -m unittest discover -s tests -t . passes from a clean tree, and the new behaviour fails against the code as it stands before the change - demonstrated, not asserted.</text>
<text id="fdzu" v="1">Branch base, and it is not main. Everything this todo cites exists only on origin/errors/actionable-refusal-surface, the branch of the still-open PR #8 for the parent todo 10326884685. On main there is no canvas/refusal.py at all, and canvas/store.py contains neither _cannot_read_repository nor _cannot_read - checked by git ls-tree and git show, both counts zero. So errno-on-repository-refusals is cut from origin/errors/actionable-refusal-surface at cd8d90e, and any half of this work branched from main names files that are not there. The suite on that branch is 263 tests, not main's 189.</text>
<section id="hp9p" v="1" title="Open question 1 - is a repository that vanished a 2 where a canvas file that vanished is a 1?">
<text id="t8zw" v="3">SETTLED, by the writer who opened this canvas, 2026-09-22: a state/canvas repository that has vanished is exit 2, where a canvas file that has vanished is exit 1 - and the errno decides what the refusal SAYS in both. Option B is the option taken. Option A is rejected on its exit code; option C is rejected because it classifies by the guard the failure landed in, which is the rule the parent change existed to remove. The reason B is right is that the two absences are not the same fact. A canvas that is not there is one missing file in a store that is otherwise intact, and the caller acts on it by creating that canvas - which is what exit 1 means here. A state/canvas that is not there is the store itself, and that absence already has a code one syscall earlier: is_repository answers False for it and _not_a_repository refuses at 2. Sending the racy route to 1 would make the exit code a function of which side of a race the caller landed on, which is the disease the ENOENT rule exists to cure; it would just be the repository's race rather than the canvas file's. Exit 1 is also false advice here - it means re-read and re-decide, and a read never initialises the repository, so the re-read raises the same refusal forever. One thing to read off the table rather than from this node: of the two costs option B's cost cell names, the second has been paid rather than accepted. The refusal no longer says it cannot tell and no longer says what that repository holds is still unknown at an ENOENT that said plainly it holds nothing, because _cannot_read_repository now branches on errno.ENOENT and hands back _not_a_repository's claim, repair and words at _not_a_repository's exit 2. The first cost stands: two sibling helpers 170 lines apart with different rules for the same errno, held apart by prose. Condition (1) of todo 10329619223 is met the second way it allows - README.md section Exit codes states in its own words why a repository that vanished is 2 where a canvas file that vanished is 1. Checked before settling: the docstring of _cannot_read_repository and README.md section Exit codes say the same thing, so neither had to change to make this settlement true.</text>
<text id="bv2j" v="1">Observed, before anything was changed. Both routes the todo names were run. EACCES (chmod 000 on .git) gives exit 2 and that is right. The vanished-repository route - .git removed between is_repository's os.stat and head_sha's rev-parse, simulated the way the parent todo's test does - gives exit 2 with 'cannot tell whether there are any commits in <dir>: looking at it was refused: [Errno 2] No such file or directory', an aftermath of 'what that repository holds is still unknown', a Canvas-About of 'errno 2 ENOENT', and a Canvas-Next whose repair is 'bin/canvas create <ledger-id> ...' - immediately under a Canvas-Exit that reads 'do not touch the canvas'. The exit code is arguable. Those last two lines are not: on ENOENT the tool can tell, it does know what the repository holds (nothing, because there is none), and a refusal that names a bin/canvas command as the repair cannot in the same breath say do not touch the canvas.</text>
<table id="uz6x" v="1">
<row id="s437" v="1">
<cell id="sm4b" v="1">Option</cell>
<cell id="zyrd" v="1">What it costs</cell>
</row>
<row id="fu7f" v="1">
<cell id="mkyr" v="1">A. Classify by errno, exactly as _cannot_read does: ENOENT returns the exit-1 refusal, every other errno stays a ToolProblem at exit 2.</cell>
<cell id="lgvs" v="2">The five call sites are not alike, and worse: the same fact already has an exit code. _not_a_repository (canvas/store.py:352) is what fires when the check itself finds no .git, and it is exit 2 - reproduced: 'state/canvas is not a git repository, so it has no sha to write against', Canvas-Exit 2, and its next action says 'a read never writes one'. Re-running the read does not fix it; only create does. So sending the racy ENOENT to exit 1 makes the exit code depend on which side of a race the caller landed - the exact disease _nothing_at's docstring says must not happen ('a race is the only difference between them, and the refusal a caller gets should not depend on which side of it they landed'). It would also send that caller to 're-read and re-decide' against a store where re-reading provably raises the same thing. Separately: is_repository's ENOENT never reaches this helper at all, because FileNotFoundError is caught above it and answered False.</cell>
</row>
<row id="pjt3" v="1">
<cell id="ymcz" v="2">CHOSEN. B. Leave every errno at exit 2 and put the reason in README.md section Exit codes: a canvas file that is not there is a true statement about the store, while a canvas repository that is not there is the tool's own environment missing, and exit 2 is the code for that. As implemented the reason README gives is narrower and better than the one written here when this option was drafted: not that the repository is the tool's environment, but that this same absence already has an exit code one syscall earlier - is_repository answers False and _not_a_repository refuses at 2 - so putting the racy route at 1 would make the code depend on which side of a race the caller landed on.</cell>
<cell id="smym" v="2">What it cost, now that it has been paid rather than estimated. Two costs were named here. The second is gone: this cell said B leaves the refusal saying what that repository holds is still unknown at exit 2 in the one case where the errno said plainly that it holds nothing. It does not, because taking B on the exit code did not mean taking it on the words - _cannot_read_repository branches on errno.ENOENT and returns _not_a_repository's claim, repair and words there, and only the code stays at 2. That distinction, between which code a refusal exits with and what it claims, is the thing this table did not have a column for and is most of what the answer turned out to be. The first cost stands and is real: two sibling helpers 170 lines apart now have visibly different rules for the same errno, and what holds them apart is a paragraph of README.md plus two docstrings. What guards it is not nothing - tests/test_store.py has the race and the plain check compared against one store, so the two routes to the same fact cannot drift apart without a failure - but nothing guards the asymmetry itself. The next person doing this refactor can still make both helpers alike and the suite will not stop them; it will only stop them making the two repository routes disagree with each other.</cell>
</row>
<row id="nyah" v="1">
<cell id="fbym" v="1">C. Split by call site: return exit 1 where the caller can act on the absence (is_repository) and exit 2 where it cannot (head_sha, the --base resolution, the ancestry check), by giving _cannot_read_repository a parameter that says which.</cell>
<cell id="rt82" v="1">This is classification by the guard the failure landed in, which is exactly the rule the parent change was made to remove. The same errno on the same directory would come back as two different exit codes depending on which command the caller happened to run, and a caller cannot see which guard it is inside. It also puts a sixth parameter on a helper with five call sites, and every one of them has to get it right for the rule to hold.</cell>
</row>
</table>
<text id="nf98" v="2">Where Case 1's code stands, on branch errno-on-repository-refusals. _cannot_read_repository branches on errno.ENOENT and returns a new helper, _no_repository_at, which gives _not_a_repository's claim and _not_a_repository's repair in _not_a_repository's words - and at _not_a_repository's exit 2. So the option taken in code is B: a repository that vanished is a 2 where a canvas file that vanished is a 1, and README.md section Exit codes says why in its own words. What the errno changed is what the tool says, not the code it exits with. EACCES is untouched and still says it cannot tell, because there the look really did fail. The question above is no longer open: node t8zw carries the settlement and the reason, and the option cell ymcz is marked CHOSEN. This node is kept as the statement of where the code is, which is a different fact from the decision and is the one that goes stale first - if _cannot_read_repository is ever changed again, this is the node that becomes a lie, not t8zw.</text>
</section>
<section id="y9hx" v="1" title="Open question 2 - may a Canvas-Next: line name a command that exits non-zero at all?">
<text id="mqxd" v="2">SETTLED, by the second writer, 2026-09-22: yes - a Canvas-Next: may name a command that exits non-zero, and one word says which one it may not. A command written after the word `run` is the repair: it is printed ready to run against real paths, running it is what makes the refused command work, and it exits 0. Everything else a next action names is either a diagnostic - `ls -ld`, `ls -l`, `df -h`, `ulimit -n`, there to show the state that produced the refusal - whose exit status is the answer and not a failure; or a form, a command with a <placeholder> in it that nobody runs as printed. So the rule the tool holds itself to is not 'every command a next action names succeeds' but 'every command a next action tells you to run succeeds'. The reason is not taste, it is what happened when I ran it. Option A - every command must exit 0 - is not implementable without gutting the surface: rendering all fifteen templates against a path that is genuinely gone and running every backticked command in each shows that four of them are not commands at all (`ulimit -n` is a shell builtin, `| cat | head -1` and `| head -1` are pipe fragments, `chown` is named bare with no operands) and that the ENOENT template's own repair exits 2 run verbatim, because it prints <ledger-id> where a ledger id goes. The remaining diagnostics exit 1 on precisely the condition their template exists for, because every way of looking at a path that is gone reports that it is gone by exiting non-zero. A would therefore either forbid a refusal about a missing path from telling a caller to look at it - the one thing a caller facing ENOENT most needs - or leave assertRepairsRun holding the hand-maintained allowlist that condition (3) was written to remove. B costs one marker, and the marker is syntactic rather than a list of command names, so a template that adds a repair nobody anticipated is covered the moment it is written.</text>
<table id="ehxj" v="1">
<row id="rysw" v="1">
<cell id="vp52" v="1">Option</cell>
<cell id="be5v" v="1">What it costs</cell>
</row>
<row id="vqpn" v="1">
<cell id="zksk" v="1">A. No. Every command a Canvas-Next: names must exit 0 when run against the state that produced the refusal. The `ls -ld` comes out of _OS_NEXT_ACTION[errno.ENOENT], and assertRepairsRun drops its chmod-only exemption and runs every command every template names.</cell>
<cell id="qdvs" v="1">A refusal can then only ever tell you to repair, never to look. The `ls -ld` on a missing path is not noise: its exit 1 and its 'No such file or directory' are the answer to which component of the path is gone, which is the thing a caller facing an ENOENT most wants to know and the thing bin/canvas cannot tell it. Dropping it means either finding a zero-exit way to ask the same question or accepting that the tool stops helping at the point the caller most needs it to.</cell>
</row>
<row id="yh66" v="1">
<cell id="vgke" v="2">CHOSEN. B. Yes, provided README.md section What a refusal prints says so and says how a caller tells the diagnostic from the repair - and provided the format carries that distinction somewhere a machine can read it, rather than leaving it to be inferred from the verb. As implemented: the distinction is the word `run` immediately in front of the command, README.md states it, and tests/test_store.py's assertRepairsRun reads it.</cell>
<cell id="lp37" v="2">What it cost, now that it has been paid rather than estimated. The estimate here was that telling the two apart means inventing a marker - a second trailer, a prefix, or a structure the line does not have - and that short of that assertRepairsRun keeps a hand-maintained list of commands it is allowed to run, which is the chmod-only exemption wearing a justification. Half right. A marker did have to be invented, but it cost one word in one template: _OS_NEXT_ACTION[errno.EACCES] is the only template in the whole table that names a command that is both runnable and a repair, so 'every existing template has to be classified against it' turned out to be one edit and not fifteen. And the marker is syntactic, not a list: assertRepairsRun runs whatever a next action marks with `run`, so a repair nobody anticipated is covered the moment somebody writes it. What is genuinely left over is that the marker is a word in prose rather than a trailer, so it is one careless sentence away from being dropped. The only thing holding it is the assertion in the other direction - every chmod a next action names must be marked - and that holds for chmod alone, because chmod is the one command in the surface that exists solely to make the refused command work. A second repair command that nobody marks would pass.</cell>
</row>
</table>
<text id="echr" v="2">For whoever takes Case 2, corrected - my first version of this node had the count wrong. Two things. (i) The reproduce command in the todo does not print what it says it does: `python3 bin/canvas read no-such-ledger 2>&1 | grep 'Canvas-Next:'` prints _nothing_at's next action, "create it with bin/canvas create no-such-ledger ...", and no ls at all, because that path never reaches refusal.os_next_action. (ii) _OS_NEXT_ACTION[errno.ENOENT] is reachable from far fewer places than grepping for os_next_action suggests. store.py has six calls to it, but four of them sit under an `except OSError` that a separate `except FileNotFoundError` above has already taken ENOENT away from - _no_canvas, the OPENCLAW_WORKSPACE stat, _write_and_commit's pre-write stat, and now _cannot_read_repository. Checked empirically, not by reading: spying on refusal.os_next_action and handing each helper a FileNotFoundError, exactly one errno 2 got through, from _cannot_write. So before Case 1's change the template had two reachable sites in store.py and now it has one, and that one is _cannot_write - which says in its own docstring that it is exit 2 for every errno, ENOENT included. Its Canvas-Next is the `ls -ld <state/canvas>` one. Case 2 is still live and still testable, including directly at the helper, the way test_an_unclassified_errno_still_refuses_in_the_shape already does.</text>
<text id="l32v" v="1">What running it showed, 2026-09-22, and two corrections to the todo's own text. I rendered every _OS_NEXT_ACTION template against a path that is genuinely gone and ran every backticked command each one names. Exit codes, verbatim: `ls -ld <gone>` 1; `ls -l <gone>` 1; `df -h <gone>` 1; `ulimit -n` 0; `chown` (named bare, no operands) 1; `bin/canvas create <ledger-id> --problem "<the problem>" --expected-value "<the expected value>"` 2, refused as 'not a usable ledger id'; `| cat | head -1` could not be run at all - [Errno 2] No such file or directory: '|'. Correction one: the todo says the repair in the ENOENT template 'succeeds and the parent todo's test runs it verbatim'. It does not succeed run verbatim, and the test does not run it. tests/test_store.py:4304 takes `bin/canvas create a-ledger-row` out of a different refusal - _nothing_at's, which fills the ledger id in - and then runs create with --problem P --expected-value V, substituting for the <the problem> placeholders by hand. Correction two: the ENOENT template says `ls -ld <path>` 'says which' directory on the way is missing. It does not. Checked both ways on the same machine: ls -ld prints one line and exits 1 whether the leaf is missing or a directory three levels up is, and the line names the path it was given either way. The diagnostic is still worth keeping - it distinguishes gone from unreadable, which is what a caller most needs - but it does not answer the question the template claims for it.</text>
<text id="ev4w" v="1">Where Case 2's code now stands, on branch errno-on-repository-refusals. canvas/refusal.py: the module docstring and the comment block over _OS_NEXT_ACTION state the rule and name the three kinds of thing a next action may hold - repair, diagnostic, form. _OS_NEXT_ACTION[errno.EACCES] is the only template in the table that names a command that is both runnable and a repair, and it now reads 'the repair is usually to run `chmod ...`' where it read '`chmod ...` is usually the repair'. No other template changed, because no other template names a runnable repair. README.md section What a refusal prints carries the rule in full, with the ls -ld exit 1 example and the bin/canvas create <ledger-id> form, and says which of the three a caller is looking at. tests/test_store.py assertRepairsRun no longer carries the chmod-only exemption: it runs every command a Canvas-Next: marks with `run`, whatever that command is, asserts it exits 0 and that it carries no <placeholder>, and asserts in the other direction that every chmod a next action names is marked as a repair - which is what stops the rule being satisfied by deleting the word. Demonstrated both ways rather than asserted. Against refusal.py exactly as it stood, the new assertion fails: 'named `chmod u+rx .../a-ledger-row.xml` without telling the caller to run it', 12 tests, FAILED (failures=1). With the change the same class is 12 tests OK and python3 -m unittest discover -s tests -t . is 263 tests OK. I also checked the assertion is not vacuous by pointing the marked repair at an invalid mode: it fails with '`chmod nosuchmode ...` is named as the repair and exited 1', so the command really is executed.</text>
<text id="g9ah" v="1">What the decision leaves open, named here so it is not mistaken for settled. (i) After this change _OS_NEXT_ACTION[errno.ENOENT] names no repair at all - a diagnostic and a form, and nothing marked `run`. That is allowed by the rule as settled, which says every command a next action tells you to run succeeds, not that every next action has a runnable repair to name. Whether a refusal ought to be required to name one is a different question and nothing in the repository asks it yet. (ii) The marker is a word in prose, not a trailer of its own, so it survives only as long as nobody rewrites the sentence around it. The single thing holding it is the converse assertion - every chmod a next action names must be marked - and that generalises to exactly one command, because chmod is the only one in the surface whose whole purpose is to make the refused command work. A second repair command that nobody marks would pass the suite. A Canvas-Repair: trailer beside Canvas-Next: would close that, at the cost of a sixth line in a block README describes as five. (iii) Both cases of todo 10329619223 are now answered on this branch, and the branch still does not descend from main - see node fdzu. A PR from it targets errors/actionable-refusal-surface, or waits for PR #8.</text>
<text id="qrpa" v="1">What the tool did about a second writer, recorded by the second writer. I arrived on this canvas holding e950b24a, the sha the first writer's handoff note names, and read it back before touching anything - it was still the head, so nothing had moved. After my own six edits I deliberately re-ran the edit to mqxd against e950b24a to see what the tool says to somebody who did not re-read. It took the hard branch: exit 1, 'refusing to write mqxd ... it moved in 1 commit(s) between --base e950b24a and 92361689, so this edit was decided against text that is no longer there. Nothing was applied and nothing was merged', then the intervening commit's subject, which is the whole --why of the edit that moved it, then git's own diff of the node from the old text to the new. Canvas-About: named the ledger id, the file, the --base I gave and the head; Canvas-Next: told me to read again, re-decide against the sha the read prints, and re-run with that --base. That is enough to act on without asking anybody: the reason the other writer changed it is in the output, so the re-decision can be made from the refusal itself rather than by reading the document again first. This node itself was inserted against the same stale e950b24a, which takes the soft branch instead - the write applies, and the same stdout that reports success carries Canvas-News and every intervening commit. What the tool does not carry either way is that somebody else is holding a base at all: read hands out a sha and says nothing about who wrote last or how old it is, so a second writer learns there was a first one from a Markdown file beside the canvas, not from the canvas.</text>
</section>
<section id="trhx" v="1" title="Outcome - what this task changed, what it decided, and what is now true that was not">
<text id="aqr3" v="1">What changed. Branch errno-on-repository-refusals, cut from origin/errors/actionable-refusal-surface at cd8d90e and NOT from main - see node fdzu. Two commits. (1) a948431, refusals: let ENOENT say the repository is not there, at the code the check already gives - canvas/store.py +60, README.md +19, tests/test_store.py +131. It adds _no_repository_at beside _not_a_repository, makes _cannot_read_repository branch on errno.ENOENT into it, states the 1-versus-2 asymmetry in README.md section Exit codes as a standing rule rather than a note about one function, and adds two tests: one that runs the race and the plain check against one store and requires them to say the same thing, one that pins EACCES so the ENOENT answer cannot be got by deleting the honest sentence for every errno. (2) 8326431, refusals: settle that a next action may look as well as repair, and mark which is which - README.md +38, canvas/refusal.py +36-1, tests/test_store.py +124-31. It states the run-marks-the-repair rule in canvas/refusal.py's docstring and over _OS_NEXT_ACTION, states it in full in README.md section What a refusal prints, changes the one template in the table that names a runnable repair so that it says the repair is usually to run chmod, and rewrites assertRepairsRun to run every command marked run, to reject a marked repair carrying a placeholder, and to require in the other direction that every chmod a next action names is marked. Net across both: README.md +57, canvas/refusal.py +36-1, canvas/store.py +60, tests/test_store.py +255-31.</text>
<text id="y44g" v="1">What is now true that was not. (1) The exit code of a refusal about the state/canvas repository no longer depends on which side of a race the caller landed on. Before this task, is_repository finding no .git refused at 2 saying the repository is not there, and the same .git vanishing one syscall later refused at 2 saying it could not tell whether there are any commits in it - same code, opposite claims, and the second one contradicted the errno 2 ENOENT printed three lines under it. Now both say the repository is not there, both name bin/canvas create as the repair, and the test that compares the two routes against one store is what keeps them from drifting apart again. (2) A caller can tell, from one word and without knowing which commands this tool uses, which of the things a Canvas-Next: names is the one that is claimed to work. Before, the claim was carried by a convention held in one test's regex - chmod is a repair, ls and df are not - and the surface had no way to admit a repair the regex had not been written for. Now the marker is in the printed line itself, the README explains it to the caller who is reading the refusal rather than the code, and assertRepairsRun executes whatever is marked. (3) tests/test_store.py no longer carries an exemption that excused a class of command from the rule the class exists to enforce. The exemption is replaced by a two-directional check, so the rule can be escaped neither by naming an unrunnable repair nor by dropping the word that marks one. (4) Two claims in todo 10329619223's own description are now known to be false and are recorded in this canvas rather than left for the next reader to rediscover: node echr on its Case 2 reproduce command, node l32v on the repair it says runs verbatim and on what ls -ld actually tells you.</text>
<text id="fxp8" v="1">Verification - the four Done when conditions of todo 10329619223, each run rather than asserted, 2026-09-22, at HEAD 8326431 from a clean tree. (1) Met the second way the condition allows: README.md line 567 begins the paragraph that states why a canvas file that vanished is 1 and the state/canvas repository that vanished is 2. Run both ways on one store: chmod 000 on state/canvas/.git gives cannot tell whether there are any commits in it, errno 13 EACCES, exit 2; the .git removed between is_repository's os.stat and the rev-parse after it gives is not a git repository - .git is not there, so there is no answer here to whether there are any commits in it, errno 2 ENOENT, exit 2, with make the first canvas with bin/canvas create as its next action. (2) Met: the rule is that a Canvas-Next: MAY name a command that exits non-zero, and README.md line 658 states it and states how a caller tells the diagnostic from the repair - the word run. canvas/refusal.py carries it at line 36 and line 145. (3) Met: assertRepairsRun's chmod-only findall is gone; it now runs every command the REPAIR pattern marks, rejects a marked repair carrying a placeholder, and asserts every chmod a next action names is marked. (4) Met and demonstrated in both directions. With canvas/ checked out at cd8d90e and tests/ left at HEAD - the new tests against the code as it stood - python3 -m unittest -v tests.test_store.EveryRefusalIsTrueAndItsNextActionRuns gives Ran 12 tests, FAILED (failures=2), one failure per case: Case 1 at assertNotIn cannot tell, Case 2 at named chmod u+rx ... without telling the caller to run it. Restored to HEAD the same twelve are OK, and python3 -m unittest discover -s tests -t . from the clean tree is Ran 263 tests in 92.483s, OK, exit 0, with the tree still clean afterwards. The full transcript of every one of these commands and its output is in .orchestrator-artifacts/done-when-verification.txt.</text>
<link id="mqu7" v="1" href="https://app.basecamp.com/3934852/buckets/48039419/todos/10329619223">Todo 10329619223 - the task this canvas is for, and the authority on its four Done when conditions. 0 comments, so the description stands unmodified.</link>
<link id="qrfs" v="1" href="https://github.com/malkovro/canvas/pull/8">PR #8, errors/actionable-refusal-surface - the parent change, still open. Branch errno-on-repository-refusals sits on top of it, so a PR from this work targets that branch or waits for #8 to merge.</link>
<text id="gjxb" v="1">This canvas is at its end, and the last edit is this one. Both open questions are settled - t8zw carries Case 1's decision and its chosen option is marked on uz6x at ymcz; mqxd carries Case 2's decision and its chosen option is marked on ehxj at vgke. Both options tables are kept rather than collapsed, which engineering-spec.md section What to copy says is right: a superseded options table is not deleted from anywhere, it is out of the current document or marked and one command away in the history, and the canvas stays small because resolution is routine and not because anybody prunes. All four Done when conditions are verified at fxp8. What remains open is named and is not this task's: node g9ah lists the three loose ends Case 2's decision leaves, and the largest of them - the run marker is a word in prose rather than a trailer, held up by a converse check that generalises to exactly one command - is the thing to raise next. One honest caveat about the word end. engineering-spec.md section Lifecycle says a canvas is frozen at done and is read-only history after it, and bin/canvas has no verb that freezes one: the seven subcommands are create, read, history, replace, insert, remove and move, and the four writing verbs go on working on this document forever. So this node is the nearest thing the tool allows - a statement, in an ordinary node, that the document is finished - and anybody with the ledger id can still write to it tomorrow. The freeze the spec describes is a property of the ledger row's state, not of the canvas, and nothing in the store enforces it.</text>
</section>
</canvas>
Transcript correction — an invocation that ran outside the wrapper
While validating the finished document I ran python3 bin/canvas read
bc-10329619223-errno-decides-the-repository-refusals directly rather than through cv.sh,
to pipe its output into a file for bin/canvas-validate. That invocation is therefore not
above with its own heading. It was a read, it exited 0, and its output was byte-identical to
the read recorded immediately before it. Recording the omission rather than quietly leaving
it out: this file is supposed to be the complete corpus, and an invocation missing from it is
worse than an invocation that had to be confessed.
The re-run below is through the wrapper, and is the one the validation was actually taken from.
python3 bin/canvas read bc-10329619223-errno-decides-the-repository-refusals
exit: 0
Canvas-Base: 02de26b71893d1d33d1559cd0fd9bcfcaff84652
<?xml version="1.0" encoding="UTF-8"?>
<canvas ledger="bc-10329619223-errno-decides-the-repository-refusals" schema="1">
<text id="bpx2" v="1">The parent change made every refusal's exit code, its repair and whatever it claims about the store derive from the errno the operating system actually returned, rather than from the guard the failure happened to land in - but one refusal helper and one next-action template were left outside that rule. canvas/store.py:582 _cannot_read_repository returns ToolProblem, exit 2, for every errno including ENOENT, where its sibling _cannot_read now returns exit 1 for ENOENT. canvas/refusal.py _OS_NEXT_ACTION[errno.ENOENT] says `ls -ld <path>` says which, and on a path that is genuinely gone that ls exits 1.</text>
<text id="bcr2" v="1">Every refusal helper in canvas/store.py that is handed an OSError chooses its exit code from the errno, _cannot_read_repository included - or README.md section Exit codes states, in its own words, why a repository that vanished is 2 where a canvas file that vanished is 1. A rule is settled and written down for whether a Canvas-Next: may name a command that exits non-zero. tests/test_store.py assertRepairsRun enforces whichever rule that settled. python3 -m unittest discover -s tests -t . passes from a clean tree, and the new behaviour fails against the code as it stands before the change - demonstrated, not asserted.</text>
<text id="fdzu" v="1">Branch base, and it is not main. Everything this todo cites exists only on origin/errors/actionable-refusal-surface, the branch of the still-open PR #8 for the parent todo 10326884685. On main there is no canvas/refusal.py at all, and canvas/store.py contains neither _cannot_read_repository nor _cannot_read - checked by git ls-tree and git show, both counts zero. So errno-on-repository-refusals is cut from origin/errors/actionable-refusal-surface at cd8d90e, and any half of this work branched from main names files that are not there. The suite on that branch is 263 tests, not main's 189.</text>
<section id="hp9p" v="1" title="Open question 1 - is a repository that vanished a 2 where a canvas file that vanished is a 1?">
<text id="t8zw" v="3">SETTLED, by the writer who opened this canvas, 2026-09-22: a state/canvas repository that has vanished is exit 2, where a canvas file that has vanished is exit 1 - and the errno decides what the refusal SAYS in both. Option B is the option taken. Option A is rejected on its exit code; option C is rejected because it classifies by the guard the failure landed in, which is the rule the parent change existed to remove. The reason B is right is that the two absences are not the same fact. A canvas that is not there is one missing file in a store that is otherwise intact, and the caller acts on it by creating that canvas - which is what exit 1 means here. A state/canvas that is not there is the store itself, and that absence already has a code one syscall earlier: is_repository answers False for it and _not_a_repository refuses at 2. Sending the racy route to 1 would make the exit code a function of which side of a race the caller landed on, which is the disease the ENOENT rule exists to cure; it would just be the repository's race rather than the canvas file's. Exit 1 is also false advice here - it means re-read and re-decide, and a read never initialises the repository, so the re-read raises the same refusal forever. One thing to read off the table rather than from this node: of the two costs option B's cost cell names, the second has been paid rather than accepted. The refusal no longer says it cannot tell and no longer says what that repository holds is still unknown at an ENOENT that said plainly it holds nothing, because _cannot_read_repository now branches on errno.ENOENT and hands back _not_a_repository's claim, repair and words at _not_a_repository's exit 2. The first cost stands: two sibling helpers 170 lines apart with different rules for the same errno, held apart by prose. Condition (1) of todo 10329619223 is met the second way it allows - README.md section Exit codes states in its own words why a repository that vanished is 2 where a canvas file that vanished is 1. Checked before settling: the docstring of _cannot_read_repository and README.md section Exit codes say the same thing, so neither had to change to make this settlement true.</text>
<text id="bv2j" v="1">Observed, before anything was changed. Both routes the todo names were run. EACCES (chmod 000 on .git) gives exit 2 and that is right. The vanished-repository route - .git removed between is_repository's os.stat and head_sha's rev-parse, simulated the way the parent todo's test does - gives exit 2 with 'cannot tell whether there are any commits in <dir>: looking at it was refused: [Errno 2] No such file or directory', an aftermath of 'what that repository holds is still unknown', a Canvas-About of 'errno 2 ENOENT', and a Canvas-Next whose repair is 'bin/canvas create <ledger-id> ...' - immediately under a Canvas-Exit that reads 'do not touch the canvas'. The exit code is arguable. Those last two lines are not: on ENOENT the tool can tell, it does know what the repository holds (nothing, because there is none), and a refusal that names a bin/canvas command as the repair cannot in the same breath say do not touch the canvas.</text>
<table id="uz6x" v="1">
<row id="s437" v="1">
<cell id="sm4b" v="1">Option</cell>
<cell id="zyrd" v="1">What it costs</cell>
</row>
<row id="fu7f" v="1">
<cell id="mkyr" v="1">A. Classify by errno, exactly as _cannot_read does: ENOENT returns the exit-1 refusal, every other errno stays a ToolProblem at exit 2.</cell>
<cell id="lgvs" v="2">The five call sites are not alike, and worse: the same fact already has an exit code. _not_a_repository (canvas/store.py:352) is what fires when the check itself finds no .git, and it is exit 2 - reproduced: 'state/canvas is not a git repository, so it has no sha to write against', Canvas-Exit 2, and its next action says 'a read never writes one'. Re-running the read does not fix it; only create does. So sending the racy ENOENT to exit 1 makes the exit code depend on which side of a race the caller landed - the exact disease _nothing_at's docstring says must not happen ('a race is the only difference between them, and the refusal a caller gets should not depend on which side of it they landed'). It would also send that caller to 're-read and re-decide' against a store where re-reading provably raises the same thing. Separately: is_repository's ENOENT never reaches this helper at all, because FileNotFoundError is caught above it and answered False.</cell>
</row>
<row id="pjt3" v="1">
<cell id="ymcz" v="2">CHOSEN. B. Leave every errno at exit 2 and put the reason in README.md section Exit codes: a canvas file that is not there is a true statement about the store, while a canvas repository that is not there is the tool's own environment missing, and exit 2 is the code for that. As implemented the reason README gives is narrower and better than the one written here when this option was drafted: not that the repository is the tool's environment, but that this same absence already has an exit code one syscall earlier - is_repository answers False and _not_a_repository refuses at 2 - so putting the racy route at 1 would make the code depend on which side of a race the caller landed on.</cell>
<cell id="smym" v="2">What it cost, now that it has been paid rather than estimated. Two costs were named here. The second is gone: this cell said B leaves the refusal saying what that repository holds is still unknown at exit 2 in the one case where the errno said plainly that it holds nothing. It does not, because taking B on the exit code did not mean taking it on the words - _cannot_read_repository branches on errno.ENOENT and returns _not_a_repository's claim, repair and words there, and only the code stays at 2. That distinction, between which code a refusal exits with and what it claims, is the thing this table did not have a column for and is most of what the answer turned out to be. The first cost stands and is real: two sibling helpers 170 lines apart now have visibly different rules for the same errno, and what holds them apart is a paragraph of README.md plus two docstrings. What guards it is not nothing - tests/test_store.py has the race and the plain check compared against one store, so the two routes to the same fact cannot drift apart without a failure - but nothing guards the asymmetry itself. The next person doing this refactor can still make both helpers alike and the suite will not stop them; it will only stop them making the two repository routes disagree with each other.</cell>
</row>
<row id="nyah" v="1">
<cell id="fbym" v="1">C. Split by call site: return exit 1 where the caller can act on the absence (is_repository) and exit 2 where it cannot (head_sha, the --base resolution, the ancestry check), by giving _cannot_read_repository a parameter that says which.</cell>
<cell id="rt82" v="1">This is classification by the guard the failure landed in, which is exactly the rule the parent change was made to remove. The same errno on the same directory would come back as two different exit codes depending on which command the caller happened to run, and a caller cannot see which guard it is inside. It also puts a sixth parameter on a helper with five call sites, and every one of them has to get it right for the rule to hold.</cell>
</row>
</table>
<text id="nf98" v="2">Where Case 1's code stands, on branch errno-on-repository-refusals. _cannot_read_repository branches on errno.ENOENT and returns a new helper, _no_repository_at, which gives _not_a_repository's claim and _not_a_repository's repair in _not_a_repository's words - and at _not_a_repository's exit 2. So the option taken in code is B: a repository that vanished is a 2 where a canvas file that vanished is a 1, and README.md section Exit codes says why in its own words. What the errno changed is what the tool says, not the code it exits with. EACCES is untouched and still says it cannot tell, because there the look really did fail. The question above is no longer open: node t8zw carries the settlement and the reason, and the option cell ymcz is marked CHOSEN. This node is kept as the statement of where the code is, which is a different fact from the decision and is the one that goes stale first - if _cannot_read_repository is ever changed again, this is the node that becomes a lie, not t8zw.</text>
</section>
<section id="y9hx" v="1" title="Open question 2 - may a Canvas-Next: line name a command that exits non-zero at all?">
<text id="mqxd" v="2">SETTLED, by the second writer, 2026-09-22: yes - a Canvas-Next: may name a command that exits non-zero, and one word says which one it may not. A command written after the word `run` is the repair: it is printed ready to run against real paths, running it is what makes the refused command work, and it exits 0. Everything else a next action names is either a diagnostic - `ls -ld`, `ls -l`, `df -h`, `ulimit -n`, there to show the state that produced the refusal - whose exit status is the answer and not a failure; or a form, a command with a <placeholder> in it that nobody runs as printed. So the rule the tool holds itself to is not 'every command a next action names succeeds' but 'every command a next action tells you to run succeeds'. The reason is not taste, it is what happened when I ran it. Option A - every command must exit 0 - is not implementable without gutting the surface: rendering all fifteen templates against a path that is genuinely gone and running every backticked command in each shows that four of them are not commands at all (`ulimit -n` is a shell builtin, `| cat | head -1` and `| head -1` are pipe fragments, `chown` is named bare with no operands) and that the ENOENT template's own repair exits 2 run verbatim, because it prints <ledger-id> where a ledger id goes. The remaining diagnostics exit 1 on precisely the condition their template exists for, because every way of looking at a path that is gone reports that it is gone by exiting non-zero. A would therefore either forbid a refusal about a missing path from telling a caller to look at it - the one thing a caller facing ENOENT most needs - or leave assertRepairsRun holding the hand-maintained allowlist that condition (3) was written to remove. B costs one marker, and the marker is syntactic rather than a list of command names, so a template that adds a repair nobody anticipated is covered the moment it is written.</text>
<table id="ehxj" v="1">
<row id="rysw" v="1">
<cell id="vp52" v="1">Option</cell>
<cell id="be5v" v="1">What it costs</cell>
</row>
<row id="vqpn" v="1">
<cell id="zksk" v="1">A. No. Every command a Canvas-Next: names must exit 0 when run against the state that produced the refusal. The `ls -ld` comes out of _OS_NEXT_ACTION[errno.ENOENT], and assertRepairsRun drops its chmod-only exemption and runs every command every template names.</cell>
<cell id="qdvs" v="1">A refusal can then only ever tell you to repair, never to look. The `ls -ld` on a missing path is not noise: its exit 1 and its 'No such file or directory' are the answer to which component of the path is gone, which is the thing a caller facing an ENOENT most wants to know and the thing bin/canvas cannot tell it. Dropping it means either finding a zero-exit way to ask the same question or accepting that the tool stops helping at the point the caller most needs it to.</cell>
</row>
<row id="yh66" v="1">
<cell id="vgke" v="2">CHOSEN. B. Yes, provided README.md section What a refusal prints says so and says how a caller tells the diagnostic from the repair - and provided the format carries that distinction somewhere a machine can read it, rather than leaving it to be inferred from the verb. As implemented: the distinction is the word `run` immediately in front of the command, README.md states it, and tests/test_store.py's assertRepairsRun reads it.</cell>
<cell id="lp37" v="2">What it cost, now that it has been paid rather than estimated. The estimate here was that telling the two apart means inventing a marker - a second trailer, a prefix, or a structure the line does not have - and that short of that assertRepairsRun keeps a hand-maintained list of commands it is allowed to run, which is the chmod-only exemption wearing a justification. Half right. A marker did have to be invented, but it cost one word in one template: _OS_NEXT_ACTION[errno.EACCES] is the only template in the whole table that names a command that is both runnable and a repair, so 'every existing template has to be classified against it' turned out to be one edit and not fifteen. And the marker is syntactic, not a list: assertRepairsRun runs whatever a next action marks with `run`, so a repair nobody anticipated is covered the moment somebody writes it. What is genuinely left over is that the marker is a word in prose rather than a trailer, so it is one careless sentence away from being dropped. The only thing holding it is the assertion in the other direction - every chmod a next action names must be marked - and that holds for chmod alone, because chmod is the one command in the surface that exists solely to make the refused command work. A second repair command that nobody marks would pass.</cell>
</row>
</table>
<text id="echr" v="2">For whoever takes Case 2, corrected - my first version of this node had the count wrong. Two things. (i) The reproduce command in the todo does not print what it says it does: `python3 bin/canvas read no-such-ledger 2>&1 | grep 'Canvas-Next:'` prints _nothing_at's next action, "create it with bin/canvas create no-such-ledger ...", and no ls at all, because that path never reaches refusal.os_next_action. (ii) _OS_NEXT_ACTION[errno.ENOENT] is reachable from far fewer places than grepping for os_next_action suggests. store.py has six calls to it, but four of them sit under an `except OSError` that a separate `except FileNotFoundError` above has already taken ENOENT away from - _no_canvas, the OPENCLAW_WORKSPACE stat, _write_and_commit's pre-write stat, and now _cannot_read_repository. Checked empirically, not by reading: spying on refusal.os_next_action and handing each helper a FileNotFoundError, exactly one errno 2 got through, from _cannot_write. So before Case 1's change the template had two reachable sites in store.py and now it has one, and that one is _cannot_write - which says in its own docstring that it is exit 2 for every errno, ENOENT included. Its Canvas-Next is the `ls -ld <state/canvas>` one. Case 2 is still live and still testable, including directly at the helper, the way test_an_unclassified_errno_still_refuses_in_the_shape already does.</text>
<text id="l32v" v="1">What running it showed, 2026-09-22, and two corrections to the todo's own text. I rendered every _OS_NEXT_ACTION template against a path that is genuinely gone and ran every backticked command each one names. Exit codes, verbatim: `ls -ld <gone>` 1; `ls -l <gone>` 1; `df -h <gone>` 1; `ulimit -n` 0; `chown` (named bare, no operands) 1; `bin/canvas create <ledger-id> --problem "<the problem>" --expected-value "<the expected value>"` 2, refused as 'not a usable ledger id'; `| cat | head -1` could not be run at all - [Errno 2] No such file or directory: '|'. Correction one: the todo says the repair in the ENOENT template 'succeeds and the parent todo's test runs it verbatim'. It does not succeed run verbatim, and the test does not run it. tests/test_store.py:4304 takes `bin/canvas create a-ledger-row` out of a different refusal - _nothing_at's, which fills the ledger id in - and then runs create with --problem P --expected-value V, substituting for the <the problem> placeholders by hand. Correction two: the ENOENT template says `ls -ld <path>` 'says which' directory on the way is missing. It does not. Checked both ways on the same machine: ls -ld prints one line and exits 1 whether the leaf is missing or a directory three levels up is, and the line names the path it was given either way. The diagnostic is still worth keeping - it distinguishes gone from unreadable, which is what a caller most needs - but it does not answer the question the template claims for it.</text>
<text id="ev4w" v="1">Where Case 2's code now stands, on branch errno-on-repository-refusals. canvas/refusal.py: the module docstring and the comment block over _OS_NEXT_ACTION state the rule and name the three kinds of thing a next action may hold - repair, diagnostic, form. _OS_NEXT_ACTION[errno.EACCES] is the only template in the table that names a command that is both runnable and a repair, and it now reads 'the repair is usually to run `chmod ...`' where it read '`chmod ...` is usually the repair'. No other template changed, because no other template names a runnable repair. README.md section What a refusal prints carries the rule in full, with the ls -ld exit 1 example and the bin/canvas create <ledger-id> form, and says which of the three a caller is looking at. tests/test_store.py assertRepairsRun no longer carries the chmod-only exemption: it runs every command a Canvas-Next: marks with `run`, whatever that command is, asserts it exits 0 and that it carries no <placeholder>, and asserts in the other direction that every chmod a next action names is marked as a repair - which is what stops the rule being satisfied by deleting the word. Demonstrated both ways rather than asserted. Against refusal.py exactly as it stood, the new assertion fails: 'named `chmod u+rx .../a-ledger-row.xml` without telling the caller to run it', 12 tests, FAILED (failures=1). With the change the same class is 12 tests OK and python3 -m unittest discover -s tests -t . is 263 tests OK. I also checked the assertion is not vacuous by pointing the marked repair at an invalid mode: it fails with '`chmod nosuchmode ...` is named as the repair and exited 1', so the command really is executed.</text>
<text id="g9ah" v="1">What the decision leaves open, named here so it is not mistaken for settled. (i) After this change _OS_NEXT_ACTION[errno.ENOENT] names no repair at all - a diagnostic and a form, and nothing marked `run`. That is allowed by the rule as settled, which says every command a next action tells you to run succeeds, not that every next action has a runnable repair to name. Whether a refusal ought to be required to name one is a different question and nothing in the repository asks it yet. (ii) The marker is a word in prose, not a trailer of its own, so it survives only as long as nobody rewrites the sentence around it. The single thing holding it is the converse assertion - every chmod a next action names must be marked - and that generalises to exactly one command, because chmod is the only one in the surface whose whole purpose is to make the refused command work. A second repair command that nobody marks would pass the suite. A Canvas-Repair: trailer beside Canvas-Next: would close that, at the cost of a sixth line in a block README describes as five. (iii) Both cases of todo 10329619223 are now answered on this branch, and the branch still does not descend from main - see node fdzu. A PR from it targets errors/actionable-refusal-surface, or waits for PR #8.</text>
<text id="qrpa" v="1">What the tool did about a second writer, recorded by the second writer. I arrived on this canvas holding e950b24a, the sha the first writer's handoff note names, and read it back before touching anything - it was still the head, so nothing had moved. After my own six edits I deliberately re-ran the edit to mqxd against e950b24a to see what the tool says to somebody who did not re-read. It took the hard branch: exit 1, 'refusing to write mqxd ... it moved in 1 commit(s) between --base e950b24a and 92361689, so this edit was decided against text that is no longer there. Nothing was applied and nothing was merged', then the intervening commit's subject, which is the whole --why of the edit that moved it, then git's own diff of the node from the old text to the new. Canvas-About: named the ledger id, the file, the --base I gave and the head; Canvas-Next: told me to read again, re-decide against the sha the read prints, and re-run with that --base. That is enough to act on without asking anybody: the reason the other writer changed it is in the output, so the re-decision can be made from the refusal itself rather than by reading the document again first. This node itself was inserted against the same stale e950b24a, which takes the soft branch instead - the write applies, and the same stdout that reports success carries Canvas-News and every intervening commit. What the tool does not carry either way is that somebody else is holding a base at all: read hands out a sha and says nothing about who wrote last or how old it is, so a second writer learns there was a first one from a Markdown file beside the canvas, not from the canvas.</text>
</section>
<section id="trhx" v="1" title="Outcome - what this task changed, what it decided, and what is now true that was not">
<text id="aqr3" v="1">What changed. Branch errno-on-repository-refusals, cut from origin/errors/actionable-refusal-surface at cd8d90e and NOT from main - see node fdzu. Two commits. (1) a948431, refusals: let ENOENT say the repository is not there, at the code the check already gives - canvas/store.py +60, README.md +19, tests/test_store.py +131. It adds _no_repository_at beside _not_a_repository, makes _cannot_read_repository branch on errno.ENOENT into it, states the 1-versus-2 asymmetry in README.md section Exit codes as a standing rule rather than a note about one function, and adds two tests: one that runs the race and the plain check against one store and requires them to say the same thing, one that pins EACCES so the ENOENT answer cannot be got by deleting the honest sentence for every errno. (2) 8326431, refusals: settle that a next action may look as well as repair, and mark which is which - README.md +38, canvas/refusal.py +36-1, tests/test_store.py +124-31. It states the run-marks-the-repair rule in canvas/refusal.py's docstring and over _OS_NEXT_ACTION, states it in full in README.md section What a refusal prints, changes the one template in the table that names a runnable repair so that it says the repair is usually to run chmod, and rewrites assertRepairsRun to run every command marked run, to reject a marked repair carrying a placeholder, and to require in the other direction that every chmod a next action names is marked. Net across both: README.md +57, canvas/refusal.py +36-1, canvas/store.py +60, tests/test_store.py +255-31.</text>
<text id="y44g" v="1">What is now true that was not. (1) The exit code of a refusal about the state/canvas repository no longer depends on which side of a race the caller landed on. Before this task, is_repository finding no .git refused at 2 saying the repository is not there, and the same .git vanishing one syscall later refused at 2 saying it could not tell whether there are any commits in it - same code, opposite claims, and the second one contradicted the errno 2 ENOENT printed three lines under it. Now both say the repository is not there, both name bin/canvas create as the repair, and the test that compares the two routes against one store is what keeps them from drifting apart again. (2) A caller can tell, from one word and without knowing which commands this tool uses, which of the things a Canvas-Next: names is the one that is claimed to work. Before, the claim was carried by a convention held in one test's regex - chmod is a repair, ls and df are not - and the surface had no way to admit a repair the regex had not been written for. Now the marker is in the printed line itself, the README explains it to the caller who is reading the refusal rather than the code, and assertRepairsRun executes whatever is marked. (3) tests/test_store.py no longer carries an exemption that excused a class of command from the rule the class exists to enforce. The exemption is replaced by a two-directional check, so the rule can be escaped neither by naming an unrunnable repair nor by dropping the word that marks one. (4) Two claims in todo 10329619223's own description are now known to be false and are recorded in this canvas rather than left for the next reader to rediscover: node echr on its Case 2 reproduce command, node l32v on the repair it says runs verbatim and on what ls -ld actually tells you.</text>
<text id="fxp8" v="1">Verification - the four Done when conditions of todo 10329619223, each run rather than asserted, 2026-09-22, at HEAD 8326431 from a clean tree. (1) Met the second way the condition allows: README.md line 567 begins the paragraph that states why a canvas file that vanished is 1 and the state/canvas repository that vanished is 2. Run both ways on one store: chmod 000 on state/canvas/.git gives cannot tell whether there are any commits in it, errno 13 EACCES, exit 2; the .git removed between is_repository's os.stat and the rev-parse after it gives is not a git repository - .git is not there, so there is no answer here to whether there are any commits in it, errno 2 ENOENT, exit 2, with make the first canvas with bin/canvas create as its next action. (2) Met: the rule is that a Canvas-Next: MAY name a command that exits non-zero, and README.md line 658 states it and states how a caller tells the diagnostic from the repair - the word run. canvas/refusal.py carries it at line 36 and line 145. (3) Met: assertRepairsRun's chmod-only findall is gone; it now runs every command the REPAIR pattern marks, rejects a marked repair carrying a placeholder, and asserts every chmod a next action names is marked. (4) Met and demonstrated in both directions. With canvas/ checked out at cd8d90e and tests/ left at HEAD - the new tests against the code as it stood - python3 -m unittest -v tests.test_store.EveryRefusalIsTrueAndItsNextActionRuns gives Ran 12 tests, FAILED (failures=2), one failure per case: Case 1 at assertNotIn cannot tell, Case 2 at named chmod u+rx ... without telling the caller to run it. Restored to HEAD the same twelve are OK, and python3 -m unittest discover -s tests -t . from the clean tree is Ran 263 tests in 92.483s, OK, exit 0, with the tree still clean afterwards. The full transcript of every one of these commands and its output is in .orchestrator-artifacts/done-when-verification.txt.</text>
<link id="mqu7" v="1" href="https://app.basecamp.com/3934852/buckets/48039419/todos/10329619223">Todo 10329619223 - the task this canvas is for, and the authority on its four Done when conditions. 0 comments, so the description stands unmodified.</link>
<link id="qrfs" v="1" href="https://github.com/malkovro/canvas/pull/8">PR #8, errors/actionable-refusal-surface - the parent change, still open. Branch errno-on-repository-refusals sits on top of it, so a PR from this work targets that branch or waits for #8 to merge.</link>
<text id="gjxb" v="1">This canvas is at its end, and the last edit is this one. Both open questions are settled - t8zw carries Case 1's decision and its chosen option is marked on uz6x at ymcz; mqxd carries Case 2's decision and its chosen option is marked on ehxj at vgke. Both options tables are kept rather than collapsed, which engineering-spec.md section What to copy says is right: a superseded options table is not deleted from anywhere, it is out of the current document or marked and one command away in the history, and the canvas stays small because resolution is routine and not because anybody prunes. All four Done when conditions are verified at fxp8. What remains open is named and is not this task's: node g9ah lists the three loose ends Case 2's decision leaves, and the largest of them - the run marker is a word in prose rather than a trailer, held up by a converse check that generalises to exactly one command - is the thing to raise next. One honest caveat about the word end. engineering-spec.md section Lifecycle says a canvas is frozen at done and is read-only history after it, and bin/canvas has no verb that freezes one: the seven subcommands are create, read, history, replace, insert, remove and move, and the four writing verbs go on working on this document forever. So this node is the nearest thing the tool allows - a statement, in an ordinary node, that the document is finished - and anybody with the ledger id can still write to it tomorrow. The freeze the spec describes is a property of the ledger row's state, not of the canvas, and nothing in the store enforces it.</text>
</section>
</canvas>
python3 bin/canvas-validate <the document the read above handed back>
exit: 0
python3 bin/canvas read bc-10329619223-errno-decides-the-repository-refusals
exit: 0
Canvas-Base: 02de26b71893d1d33d1559cd0fd9bcfcaff84652
<?xml version="1.0" encoding="UTF-8"?>
<canvas ledger="bc-10329619223-errno-decides-the-repository-refusals" schema="1">
<text id="bpx2" v="1">The parent change made every refusal's exit code, its repair and whatever it claims about the store derive from the errno the operating system actually returned, rather than from the guard the failure happened to land in - but one refusal helper and one next-action template were left outside that rule. canvas/store.py:582 _cannot_read_repository returns ToolProblem, exit 2, for every errno including ENOENT, where its sibling _cannot_read now returns exit 1 for ENOENT. canvas/refusal.py _OS_NEXT_ACTION[errno.ENOENT] says `ls -ld <path>` says which, and on a path that is genuinely gone that ls exits 1.</text>
<text id="bcr2" v="1">Every refusal helper in canvas/store.py that is handed an OSError chooses its exit code from the errno, _cannot_read_repository included - or README.md section Exit codes states, in its own words, why a repository that vanished is 2 where a canvas file that vanished is 1. A rule is settled and written down for whether a Canvas-Next: may name a command that exits non-zero. tests/test_store.py assertRepairsRun enforces whichever rule that settled. python3 -m unittest discover -s tests -t . passes from a clean tree, and the new behaviour fails against the code as it stands before the change - demonstrated, not asserted.</text>
<text id="fdzu" v="1">Branch base, and it is not main. Everything this todo cites exists only on origin/errors/actionable-refusal-surface, the branch of the still-open PR #8 for the parent todo 10326884685. On main there is no canvas/refusal.py at all, and canvas/store.py contains neither _cannot_read_repository nor _cannot_read - checked by git ls-tree and git show, both counts zero. So errno-on-repository-refusals is cut from origin/errors/actionable-refusal-surface at cd8d90e, and any half of this work branched from main names files that are not there. The suite on that branch is 263 tests, not main's 189.</text>
<section id="hp9p" v="1" title="Open question 1 - is a repository that vanished a 2 where a canvas file that vanished is a 1?">
<text id="t8zw" v="3">SETTLED, by the writer who opened this canvas, 2026-09-22: a state/canvas repository that has vanished is exit 2, where a canvas file that has vanished is exit 1 - and the errno decides what the refusal SAYS in both. Option B is the option taken. Option A is rejected on its exit code; option C is rejected because it classifies by the guard the failure landed in, which is the rule the parent change existed to remove. The reason B is right is that the two absences are not the same fact. A canvas that is not there is one missing file in a store that is otherwise intact, and the caller acts on it by creating that canvas - which is what exit 1 means here. A state/canvas that is not there is the store itself, and that absence already has a code one syscall earlier: is_repository answers False for it and _not_a_repository refuses at 2. Sending the racy route to 1 would make the exit code a function of which side of a race the caller landed on, which is the disease the ENOENT rule exists to cure; it would just be the repository's race rather than the canvas file's. Exit 1 is also false advice here - it means re-read and re-decide, and a read never initialises the repository, so the re-read raises the same refusal forever. One thing to read off the table rather than from this node: of the two costs option B's cost cell names, the second has been paid rather than accepted. The refusal no longer says it cannot tell and no longer says what that repository holds is still unknown at an ENOENT that said plainly it holds nothing, because _cannot_read_repository now branches on errno.ENOENT and hands back _not_a_repository's claim, repair and words at _not_a_repository's exit 2. The first cost stands: two sibling helpers 170 lines apart with different rules for the same errno, held apart by prose. Condition (1) of todo 10329619223 is met the second way it allows - README.md section Exit codes states in its own words why a repository that vanished is 2 where a canvas file that vanished is 1. Checked before settling: the docstring of _cannot_read_repository and README.md section Exit codes say the same thing, so neither had to change to make this settlement true.</text>
<text id="bv2j" v="1">Observed, before anything was changed. Both routes the todo names were run. EACCES (chmod 000 on .git) gives exit 2 and that is right. The vanished-repository route - .git removed between is_repository's os.stat and head_sha's rev-parse, simulated the way the parent todo's test does - gives exit 2 with 'cannot tell whether there are any commits in <dir>: looking at it was refused: [Errno 2] No such file or directory', an aftermath of 'what that repository holds is still unknown', a Canvas-About of 'errno 2 ENOENT', and a Canvas-Next whose repair is 'bin/canvas create <ledger-id> ...' - immediately under a Canvas-Exit that reads 'do not touch the canvas'. The exit code is arguable. Those last two lines are not: on ENOENT the tool can tell, it does know what the repository holds (nothing, because there is none), and a refusal that names a bin/canvas command as the repair cannot in the same breath say do not touch the canvas.</text>
<table id="uz6x" v="1">
<row id="s437" v="1">
<cell id="sm4b" v="1">Option</cell>
<cell id="zyrd" v="1">What it costs</cell>
</row>
<row id="fu7f" v="1">
<cell id="mkyr" v="1">A. Classify by errno, exactly as _cannot_read does: ENOENT returns the exit-1 refusal, every other errno stays a ToolProblem at exit 2.</cell>
<cell id="lgvs" v="2">The five call sites are not alike, and worse: the same fact already has an exit code. _not_a_repository (canvas/store.py:352) is what fires when the check itself finds no .git, and it is exit 2 - reproduced: 'state/canvas is not a git repository, so it has no sha to write against', Canvas-Exit 2, and its next action says 'a read never writes one'. Re-running the read does not fix it; only create does. So sending the racy ENOENT to exit 1 makes the exit code depend on which side of a race the caller landed - the exact disease _nothing_at's docstring says must not happen ('a race is the only difference between them, and the refusal a caller gets should not depend on which side of it they landed'). It would also send that caller to 're-read and re-decide' against a store where re-reading provably raises the same thing. Separately: is_repository's ENOENT never reaches this helper at all, because FileNotFoundError is caught above it and answered False.</cell>
</row>
<row id="pjt3" v="1">
<cell id="ymcz" v="2">CHOSEN. B. Leave every errno at exit 2 and put the reason in README.md section Exit codes: a canvas file that is not there is a true statement about the store, while a canvas repository that is not there is the tool's own environment missing, and exit 2 is the code for that. As implemented the reason README gives is narrower and better than the one written here when this option was drafted: not that the repository is the tool's environment, but that this same absence already has an exit code one syscall earlier - is_repository answers False and _not_a_repository refuses at 2 - so putting the racy route at 1 would make the code depend on which side of a race the caller landed on.</cell>
<cell id="smym" v="2">What it cost, now that it has been paid rather than estimated. Two costs were named here. The second is gone: this cell said B leaves the refusal saying what that repository holds is still unknown at exit 2 in the one case where the errno said plainly that it holds nothing. It does not, because taking B on the exit code did not mean taking it on the words - _cannot_read_repository branches on errno.ENOENT and returns _not_a_repository's claim, repair and words there, and only the code stays at 2. That distinction, between which code a refusal exits with and what it claims, is the thing this table did not have a column for and is most of what the answer turned out to be. The first cost stands and is real: two sibling helpers 170 lines apart now have visibly different rules for the same errno, and what holds them apart is a paragraph of README.md plus two docstrings. What guards it is not nothing - tests/test_store.py has the race and the plain check compared against one store, so the two routes to the same fact cannot drift apart without a failure - but nothing guards the asymmetry itself. The next person doing this refactor can still make both helpers alike and the suite will not stop them; it will only stop them making the two repository routes disagree with each other.</cell>
</row>
<row id="nyah" v="1">
<cell id="fbym" v="1">C. Split by call site: return exit 1 where the caller can act on the absence (is_repository) and exit 2 where it cannot (head_sha, the --base resolution, the ancestry check), by giving _cannot_read_repository a parameter that says which.</cell>
<cell id="rt82" v="1">This is classification by the guard the failure landed in, which is exactly the rule the parent change was made to remove. The same errno on the same directory would come back as two different exit codes depending on which command the caller happened to run, and a caller cannot see which guard it is inside. It also puts a sixth parameter on a helper with five call sites, and every one of them has to get it right for the rule to hold.</cell>
</row>
</table>
<text id="nf98" v="2">Where Case 1's code stands, on branch errno-on-repository-refusals. _cannot_read_repository branches on errno.ENOENT and returns a new helper, _no_repository_at, which gives _not_a_repository's claim and _not_a_repository's repair in _not_a_repository's words - and at _not_a_repository's exit 2. So the option taken in code is B: a repository that vanished is a 2 where a canvas file that vanished is a 1, and README.md section Exit codes says why in its own words. What the errno changed is what the tool says, not the code it exits with. EACCES is untouched and still says it cannot tell, because there the look really did fail. The question above is no longer open: node t8zw carries the settlement and the reason, and the option cell ymcz is marked CHOSEN. This node is kept as the statement of where the code is, which is a different fact from the decision and is the one that goes stale first - if _cannot_read_repository is ever changed again, this is the node that becomes a lie, not t8zw.</text>
</section>
<section id="y9hx" v="1" title="Open question 2 - may a Canvas-Next: line name a command that exits non-zero at all?">
<text id="mqxd" v="2">SETTLED, by the second writer, 2026-09-22: yes - a Canvas-Next: may name a command that exits non-zero, and one word says which one it may not. A command written after the word `run` is the repair: it is printed ready to run against real paths, running it is what makes the refused command work, and it exits 0. Everything else a next action names is either a diagnostic - `ls -ld`, `ls -l`, `df -h`, `ulimit -n`, there to show the state that produced the refusal - whose exit status is the answer and not a failure; or a form, a command with a <placeholder> in it that nobody runs as printed. So the rule the tool holds itself to is not 'every command a next action names succeeds' but 'every command a next action tells you to run succeeds'. The reason is not taste, it is what happened when I ran it. Option A - every command must exit 0 - is not implementable without gutting the surface: rendering all fifteen templates against a path that is genuinely gone and running every backticked command in each shows that four of them are not commands at all (`ulimit -n` is a shell builtin, `| cat | head -1` and `| head -1` are pipe fragments, `chown` is named bare with no operands) and that the ENOENT template's own repair exits 2 run verbatim, because it prints <ledger-id> where a ledger id goes. The remaining diagnostics exit 1 on precisely the condition their template exists for, because every way of looking at a path that is gone reports that it is gone by exiting non-zero. A would therefore either forbid a refusal about a missing path from telling a caller to look at it - the one thing a caller facing ENOENT most needs - or leave assertRepairsRun holding the hand-maintained allowlist that condition (3) was written to remove. B costs one marker, and the marker is syntactic rather than a list of command names, so a template that adds a repair nobody anticipated is covered the moment it is written.</text>
<table id="ehxj" v="1">
<row id="rysw" v="1">
<cell id="vp52" v="1">Option</cell>
<cell id="be5v" v="1">What it costs</cell>
</row>
<row id="vqpn" v="1">
<cell id="zksk" v="1">A. No. Every command a Canvas-Next: names must exit 0 when run against the state that produced the refusal. The `ls -ld` comes out of _OS_NEXT_ACTION[errno.ENOENT], and assertRepairsRun drops its chmod-only exemption and runs every command every template names.</cell>
<cell id="qdvs" v="1">A refusal can then only ever tell you to repair, never to look. The `ls -ld` on a missing path is not noise: its exit 1 and its 'No such file or directory' are the answer to which component of the path is gone, which is the thing a caller facing an ENOENT most wants to know and the thing bin/canvas cannot tell it. Dropping it means either finding a zero-exit way to ask the same question or accepting that the tool stops helping at the point the caller most needs it to.</cell>
</row>
<row id="yh66" v="1">
<cell id="vgke" v="2">CHOSEN. B. Yes, provided README.md section What a refusal prints says so and says how a caller tells the diagnostic from the repair - and provided the format carries that distinction somewhere a machine can read it, rather than leaving it to be inferred from the verb. As implemented: the distinction is the word `run` immediately in front of the command, README.md states it, and tests/test_store.py's assertRepairsRun reads it.</cell>
<cell id="lp37" v="2">What it cost, now that it has been paid rather than estimated. The estimate here was that telling the two apart means inventing a marker - a second trailer, a prefix, or a structure the line does not have - and that short of that assertRepairsRun keeps a hand-maintained list of commands it is allowed to run, which is the chmod-only exemption wearing a justification. Half right. A marker did have to be invented, but it cost one word in one template: _OS_NEXT_ACTION[errno.EACCES] is the only template in the whole table that names a command that is both runnable and a repair, so 'every existing template has to be classified against it' turned out to be one edit and not fifteen. And the marker is syntactic, not a list: assertRepairsRun runs whatever a next action marks with `run`, so a repair nobody anticipated is covered the moment somebody writes it. What is genuinely left over is that the marker is a word in prose rather than a trailer, so it is one careless sentence away from being dropped. The only thing holding it is the assertion in the other direction - every chmod a next action names must be marked - and that holds for chmod alone, because chmod is the one command in the surface that exists solely to make the refused command work. A second repair command that nobody marks would pass.</cell>
</row>
</table>
<text id="echr" v="2">For whoever takes Case 2, corrected - my first version of this node had the count wrong. Two things. (i) The reproduce command in the todo does not print what it says it does: `python3 bin/canvas read no-such-ledger 2>&1 | grep 'Canvas-Next:'` prints _nothing_at's next action, "create it with bin/canvas create no-such-ledger ...", and no ls at all, because that path never reaches refusal.os_next_action. (ii) _OS_NEXT_ACTION[errno.ENOENT] is reachable from far fewer places than grepping for os_next_action suggests. store.py has six calls to it, but four of them sit under an `except OSError` that a separate `except FileNotFoundError` above has already taken ENOENT away from - _no_canvas, the OPENCLAW_WORKSPACE stat, _write_and_commit's pre-write stat, and now _cannot_read_repository. Checked empirically, not by reading: spying on refusal.os_next_action and handing each helper a FileNotFoundError, exactly one errno 2 got through, from _cannot_write. So before Case 1's change the template had two reachable sites in store.py and now it has one, and that one is _cannot_write - which says in its own docstring that it is exit 2 for every errno, ENOENT included. Its Canvas-Next is the `ls -ld <state/canvas>` one. Case 2 is still live and still testable, including directly at the helper, the way test_an_unclassified_errno_still_refuses_in_the_shape already does.</text>
<text id="l32v" v="1">What running it showed, 2026-09-22, and two corrections to the todo's own text. I rendered every _OS_NEXT_ACTION template against a path that is genuinely gone and ran every backticked command each one names. Exit codes, verbatim: `ls -ld <gone>` 1; `ls -l <gone>` 1; `df -h <gone>` 1; `ulimit -n` 0; `chown` (named bare, no operands) 1; `bin/canvas create <ledger-id> --problem "<the problem>" --expected-value "<the expected value>"` 2, refused as 'not a usable ledger id'; `| cat | head -1` could not be run at all - [Errno 2] No such file or directory: '|'. Correction one: the todo says the repair in the ENOENT template 'succeeds and the parent todo's test runs it verbatim'. It does not succeed run verbatim, and the test does not run it. tests/test_store.py:4304 takes `bin/canvas create a-ledger-row` out of a different refusal - _nothing_at's, which fills the ledger id in - and then runs create with --problem P --expected-value V, substituting for the <the problem> placeholders by hand. Correction two: the ENOENT template says `ls -ld <path>` 'says which' directory on the way is missing. It does not. Checked both ways on the same machine: ls -ld prints one line and exits 1 whether the leaf is missing or a directory three levels up is, and the line names the path it was given either way. The diagnostic is still worth keeping - it distinguishes gone from unreadable, which is what a caller most needs - but it does not answer the question the template claims for it.</text>
<text id="ev4w" v="1">Where Case 2's code now stands, on branch errno-on-repository-refusals. canvas/refusal.py: the module docstring and the comment block over _OS_NEXT_ACTION state the rule and name the three kinds of thing a next action may hold - repair, diagnostic, form. _OS_NEXT_ACTION[errno.EACCES] is the only template in the table that names a command that is both runnable and a repair, and it now reads 'the repair is usually to run `chmod ...`' where it read '`chmod ...` is usually the repair'. No other template changed, because no other template names a runnable repair. README.md section What a refusal prints carries the rule in full, with the ls -ld exit 1 example and the bin/canvas create <ledger-id> form, and says which of the three a caller is looking at. tests/test_store.py assertRepairsRun no longer carries the chmod-only exemption: it runs every command a Canvas-Next: marks with `run`, whatever that command is, asserts it exits 0 and that it carries no <placeholder>, and asserts in the other direction that every chmod a next action names is marked as a repair - which is what stops the rule being satisfied by deleting the word. Demonstrated both ways rather than asserted. Against refusal.py exactly as it stood, the new assertion fails: 'named `chmod u+rx .../a-ledger-row.xml` without telling the caller to run it', 12 tests, FAILED (failures=1). With the change the same class is 12 tests OK and python3 -m unittest discover -s tests -t . is 263 tests OK. I also checked the assertion is not vacuous by pointing the marked repair at an invalid mode: it fails with '`chmod nosuchmode ...` is named as the repair and exited 1', so the command really is executed.</text>
<text id="g9ah" v="1">What the decision leaves open, named here so it is not mistaken for settled. (i) After this change _OS_NEXT_ACTION[errno.ENOENT] names no repair at all - a diagnostic and a form, and nothing marked `run`. That is allowed by the rule as settled, which says every command a next action tells you to run succeeds, not that every next action has a runnable repair to name. Whether a refusal ought to be required to name one is a different question and nothing in the repository asks it yet. (ii) The marker is a word in prose, not a trailer of its own, so it survives only as long as nobody rewrites the sentence around it. The single thing holding it is the converse assertion - every chmod a next action names must be marked - and that generalises to exactly one command, because chmod is the only one in the surface whose whole purpose is to make the refused command work. A second repair command that nobody marks would pass the suite. A Canvas-Repair: trailer beside Canvas-Next: would close that, at the cost of a sixth line in a block README describes as five. (iii) Both cases of todo 10329619223 are now answered on this branch, and the branch still does not descend from main - see node fdzu. A PR from it targets errors/actionable-refusal-surface, or waits for PR #8.</text>
<text id="qrpa" v="1">What the tool did about a second writer, recorded by the second writer. I arrived on this canvas holding e950b24a, the sha the first writer's handoff note names, and read it back before touching anything - it was still the head, so nothing had moved. After my own six edits I deliberately re-ran the edit to mqxd against e950b24a to see what the tool says to somebody who did not re-read. It took the hard branch: exit 1, 'refusing to write mqxd ... it moved in 1 commit(s) between --base e950b24a and 92361689, so this edit was decided against text that is no longer there. Nothing was applied and nothing was merged', then the intervening commit's subject, which is the whole --why of the edit that moved it, then git's own diff of the node from the old text to the new. Canvas-About: named the ledger id, the file, the --base I gave and the head; Canvas-Next: told me to read again, re-decide against the sha the read prints, and re-run with that --base. That is enough to act on without asking anybody: the reason the other writer changed it is in the output, so the re-decision can be made from the refusal itself rather than by reading the document again first. This node itself was inserted against the same stale e950b24a, which takes the soft branch instead - the write applies, and the same stdout that reports success carries Canvas-News and every intervening commit. What the tool does not carry either way is that somebody else is holding a base at all: read hands out a sha and says nothing about who wrote last or how old it is, so a second writer learns there was a first one from a Markdown file beside the canvas, not from the canvas.</text>
</section>
<section id="trhx" v="1" title="Outcome - what this task changed, what it decided, and what is now true that was not">
<text id="aqr3" v="1">What changed. Branch errno-on-repository-refusals, cut from origin/errors/actionable-refusal-surface at cd8d90e and NOT from main - see node fdzu. Two commits. (1) a948431, refusals: let ENOENT say the repository is not there, at the code the check already gives - canvas/store.py +60, README.md +19, tests/test_store.py +131. It adds _no_repository_at beside _not_a_repository, makes _cannot_read_repository branch on errno.ENOENT into it, states the 1-versus-2 asymmetry in README.md section Exit codes as a standing rule rather than a note about one function, and adds two tests: one that runs the race and the plain check against one store and requires them to say the same thing, one that pins EACCES so the ENOENT answer cannot be got by deleting the honest sentence for every errno. (2) 8326431, refusals: settle that a next action may look as well as repair, and mark which is which - README.md +38, canvas/refusal.py +36-1, tests/test_store.py +124-31. It states the run-marks-the-repair rule in canvas/refusal.py's docstring and over _OS_NEXT_ACTION, states it in full in README.md section What a refusal prints, changes the one template in the table that names a runnable repair so that it says the repair is usually to run chmod, and rewrites assertRepairsRun to run every command marked run, to reject a marked repair carrying a placeholder, and to require in the other direction that every chmod a next action names is marked. Net across both: README.md +57, canvas/refusal.py +36-1, canvas/store.py +60, tests/test_store.py +255-31.</text>
<text id="y44g" v="1">What is now true that was not. (1) The exit code of a refusal about the state/canvas repository no longer depends on which side of a race the caller landed on. Before this task, is_repository finding no .git refused at 2 saying the repository is not there, and the same .git vanishing one syscall later refused at 2 saying it could not tell whether there are any commits in it - same code, opposite claims, and the second one contradicted the errno 2 ENOENT printed three lines under it. Now both say the repository is not there, both name bin/canvas create as the repair, and the test that compares the two routes against one store is what keeps them from drifting apart again. (2) A caller can tell, from one word and without knowing which commands this tool uses, which of the things a Canvas-Next: names is the one that is claimed to work. Before, the claim was carried by a convention held in one test's regex - chmod is a repair, ls and df are not - and the surface had no way to admit a repair the regex had not been written for. Now the marker is in the printed line itself, the README explains it to the caller who is reading the refusal rather than the code, and assertRepairsRun executes whatever is marked. (3) tests/test_store.py no longer carries an exemption that excused a class of command from the rule the class exists to enforce. The exemption is replaced by a two-directional check, so the rule can be escaped neither by naming an unrunnable repair nor by dropping the word that marks one. (4) Two claims in todo 10329619223's own description are now known to be false and are recorded in this canvas rather than left for the next reader to rediscover: node echr on its Case 2 reproduce command, node l32v on the repair it says runs verbatim and on what ls -ld actually tells you.</text>
<text id="fxp8" v="1">Verification - the four Done when conditions of todo 10329619223, each run rather than asserted, 2026-09-22, at HEAD 8326431 from a clean tree. (1) Met the second way the condition allows: README.md line 567 begins the paragraph that states why a canvas file that vanished is 1 and the state/canvas repository that vanished is 2. Run both ways on one store: chmod 000 on state/canvas/.git gives cannot tell whether there are any commits in it, errno 13 EACCES, exit 2; the .git removed between is_repository's os.stat and the rev-parse after it gives is not a git repository - .git is not there, so there is no answer here to whether there are any commits in it, errno 2 ENOENT, exit 2, with make the first canvas with bin/canvas create as its next action. (2) Met: the rule is that a Canvas-Next: MAY name a command that exits non-zero, and README.md line 658 states it and states how a caller tells the diagnostic from the repair - the word run. canvas/refusal.py carries it at line 36 and line 145. (3) Met: assertRepairsRun's chmod-only findall is gone; it now runs every command the REPAIR pattern marks, rejects a marked repair carrying a placeholder, and asserts every chmod a next action names is marked. (4) Met and demonstrated in both directions. With canvas/ checked out at cd8d90e and tests/ left at HEAD - the new tests against the code as it stood - python3 -m unittest -v tests.test_store.EveryRefusalIsTrueAndItsNextActionRuns gives Ran 12 tests, FAILED (failures=2), one failure per case: Case 1 at assertNotIn cannot tell, Case 2 at named chmod u+rx ... without telling the caller to run it. Restored to HEAD the same twelve are OK, and python3 -m unittest discover -s tests -t . from the clean tree is Ran 263 tests in 92.483s, OK, exit 0, with the tree still clean afterwards. The full transcript of every one of these commands and its output is in .orchestrator-artifacts/done-when-verification.txt.</text>
<link id="mqu7" v="1" href="https://app.basecamp.com/3934852/buckets/48039419/todos/10329619223">Todo 10329619223 - the task this canvas is for, and the authority on its four Done when conditions. 0 comments, so the description stands unmodified.</link>
<link id="qrfs" v="1" href="https://github.com/malkovro/canvas/pull/8">PR #8, errors/actionable-refusal-surface - the parent change, still open. Branch errno-on-repository-refusals sits on top of it, so a PR from this work targets that branch or waits for #8 to merge.</link>
<text id="gjxb" v="1">This canvas is at its end, and the last edit is this one. Both open questions are settled - t8zw carries Case 1's decision and its chosen option is marked on uz6x at ymcz; mqxd carries Case 2's decision and its chosen option is marked on ehxj at vgke. Both options tables are kept rather than collapsed, which engineering-spec.md section What to copy says is right: a superseded options table is not deleted from anywhere, it is out of the current document or marked and one command away in the history, and the canvas stays small because resolution is routine and not because anybody prunes. All four Done when conditions are verified at fxp8. What remains open is named and is not this task's: node g9ah lists the three loose ends Case 2's decision leaves, and the largest of them - the run marker is a word in prose rather than a trailer, held up by a converse check that generalises to exactly one command - is the thing to raise next. One honest caveat about the word end. engineering-spec.md section Lifecycle says a canvas is frozen at done and is read-only history after it, and bin/canvas has no verb that freezes one: the seven subcommands are create, read, history, replace, insert, remove and move, and the four writing verbs go on working on this document forever. So this node is the nearest thing the tool allows - a statement, in an ordinary node, that the document is finished - and anybody with the ledger id can still write to it tomorrow. The freeze the spec describes is a property of the ledger row's state, not of the canvas, and nothing in the store enforces it.</text>
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