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* fix(#3802): resolve the heredoc body before validating the commit subject With hooks.community: true, gsd-validate-commit.sh blocked EVERY heredoc-form commit with CONVENTIONAL_COMMITS_VIOLATION regardless of the message, including Claude Code's own documented idiom: git commit -m "$(cat <<'EOF' feat(auth): add login flow EOF )" Reproduced before changing anything: conforming heredoc -> exit 2; plain -m "feat(auth): add login flow" -> exit 0. Root cause is the extraction regex `-m[[:space:]]+"([^"]+)"`. Bash `[^"]` matches newlines, so the capture ran from the quote after -m to the FINAL quote at `)"`, swallowing the whole span. `head -1` then returned the literal `$(cat <<'EOF'` as the subject, which can never satisfy Conventional Commits. Fixed by not answering a regex bug with another regex. hooks/lib/git-cmd.js already exists because "a naive regex misses all three" invocation forms, and extractBranchArgument is the established precedent for pulling an argument off a git command line. extractCommitSubject joins it on the same tokenizeShellLike seam — which, checked first, already returns the entire heredoc span as ONE token, leaving only "resolve the body to its first line" as new logic. Because the walk starts at the subcommand, `git -C <path> commit` and env-prefixed invocations now extract correctly too — forms the raw string scan never handled. Deliberately unchanged, and pinned as such: a glued `-mfeat: x` and `--message=...` still yield no message, exactly as the regex left them. The fix stays scoped to the reported defect rather than widening on a true observation. Two things I got wrong and corrected by measuring rather than reasoning: - I expected `git commit -m ""` to be blocked. Checked against the ORIGINAL hook: allowed before, allowed now, identical. The scanner drops the empty token so it takes the null path. My expectation was wrong, not the code. - That exposed a false comment I had just written, claiming the exit-status split prevents silently allowing `-m ""`. It does not. The split IS load-bearing, but for a heredoc whose body's first line is blank, which resolves to an empty subject and is correctly blocked. The comment now names the real case and records that `-m ""` is not it. Tests at both layers: 9 unit rows on extractCommitSubject beside its sibling in tests/worktree-safety.test.cjs, and 5 behavioral rows piping real PreToolUse payloads through the hook in tests/hooks-opt-in.test.cjs. Replacing firstLineOfMessageArg with a plain first-line return reds 8 of them across both files. (A first mutation attempt silently no-opped and reported green — the mutated body is echoed in the transcript for the run that counted.) Out of scope, per the issue: the hooks.commit_types config surface, split off by the maintainer as #3811 and explicitly sequenced after this. Verified: `npm run lint:ci` exit 0. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com> * fix(#3802): confine the fix to heredoc resolution, closing four regressions Codex review of the first attempt. It was right, and the finding is one my own rules already name: a true observation is not a licence to widen the diff. The first attempt replaced the shell's `-m` extraction with a token walk. That looked like the better abstraction — this module exists precisely because a naive regex misses invocation forms — but selecting WHICH argument is the message was never the defect, and changing it regressed four forms that upstream allowed, plus opened a bypass: - `git commit -- -m WIP` -- introduces pathspecs; `-m` is a path - `git commit --amend && echo -m WIP` a later command's flag became the message - `git commit -m "" --allow-empty-message` the shared scanner drops empty tokens, so the next flag became the message - `git commit -m WIP` unquoted argument - `-m "WIP notes <<EOF\nfix: smuggled subject"` was ALLOWED — the opener was recognised unanchored, so validation skipped past the real, non-conforming subject. An enforcement bypass, not a misclassification. Now confined to the actual defect. The shell's `-m` capture is restored byte for byte, and only the subject-from-message step is delegated, to a PURE STRING helper `resolveCommitSubject()` that never tokenizes. Verified as a differential against the upstream hook run inside the real tree: the only behaviours that change are the two intended heredoc rows (2 -> 0); all four forms above read identical, and the bypass case blocks. That differential also corrected my own control. An earlier comparison ran the upstream hook from a scratch directory, where its `lib/` could not resolve `../../gsd-core/bin/lib/token-scanner.cjs`, so the classifier failed open and reported exit 0 for everything. That made a real regression look pre-existing. Re-run inside the tree, `<<-"TAG"` (a double-quoted tag nested in the double-quoted argument) is genuinely pre-existing — the capture truncates — and is now recorded as a known limitation rather than silently "fixed". Also fixed from the review: - `<<-` strips leading TABS from body lines; returning the raw line blocked a conforming message. - a non-identifier tag such as `END-MSG` is a valid bash word and was rejected. - an immediately-following terminator is an EMPTY message, not a subject. - a node/library failure now falls back to the previous `head -1` instead of skipping validation, so a broken extractor degrades to old behaviour rather than becoming a new silent-allow path. Tests strengthened per the review: the opener-spelling rows now assert BOTH directions per spelling, since "conforming passes" alone would also pass if the resolver returned an empty subject for a spelling it failed to parse. Added differential rows pinning the five previously-allowed forms, and a row for the bypass. Dropped two rows whose comments claimed the raw scan could not handle `-C`/env-prefix invocations — it could; the claim was wrong. Replacing resolveCommitSubject with a plain first-line return reds 9 rows across both files. (Mutant body echoed in the transcript; an earlier mutation attempt on this branch silently no-opped and reported green.) Verified: `npm run lint:ci` exit 0. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com> * fix(#3802): keep the installed hook runtime-neutral `hooks/lib/git-cmd.js` ships into every runtime, including hermes and qwen, where tests/install.test.cjs enforces that no Claude reference leaks into the installed tree. My JSDoc named the idiom after the runtime that documents it. Reworded to describe the SHAPE rather than the vendor; the runtime is still named in the changeset, which feeds CHANGELOG.md where such references are allowed, and in the tests, which are not installed. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com> * chore(#3802): backfill changeset pr number The fragment shipped with the documented `pr: 0` placeholder, which the changeset lint treats as always-silent, because the number does not exist until the PR is opened. Backfilled to 3816 now that it does. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com> * fix(#3802): close the truncated-capture hole, add the required test artifacts Review round 1. Major 3 was the one that mattered, and it disproved a claim I had stated in falsifiable form — the PR body said only two behaviours change; the differential found five. Major 3 — an embedded `"` truncates the `-m` capture, so the resolver received a PREFIX of the real subject and the length gate measured the wrong string. Before this fix the whole form was blocked outright, so the gate was unreachable; the fix opened the path and then mismeasured it. A new enforcement hole, so it is CLOSED here rather than declared. Closed precisely rather than bluntly. A first attempt refused to resolve any body with no terminator, which also blocked commits whose SUBJECT was intact and whose quote sat further down the body — a false positive of its own. Truncation is only fatal to the line it lands IN, and a captured line is complete exactly when another line follows it, because the capture kept its newline. So an unterminated body whose subject line is followed by more text stays measurable; only a subject line running to the end of a truncated capture falls back to the opener, which fails the format gate exactly as this form did before the fix. Major 1 — fast-check property rows for the new parser, via the shared seeded setup helper rather than requiring fast-check directly, per repo convention: totality (a security property here, since an exception on this path fails OPEN), idempotency, and that the result is always a single line drawn from the input — the third catches a resolver that concatenated or trimmed while satisfying the first two. Major 2 — the 72-char gate is now exercised at {71, 72, 73} on the RESOLVED heredoc subject, with the fixture length asserted so a mis-built fixture cannot silently pass. 92 chars did not show which side of `> 72` the code sits on. Minor 1 — leading blank body lines are skipped, as git's cleanup=whitespace does. A conforming commit written that way was still blocked, which is the same defect class #3802 reports. Nit 1 — a backslash-escaped delimiter (`<<\EOF`) is now the same delimiter rather than failing closed on a delimiter that includes the backslash. Nit 5 — changeset trimmed from 2,208 chars of design note to the user-visible change. Mutation discipline, including a correction to my own: dropping the truncation guard reds the unit rows, and the pre-review naive shape reds the hook-level row too. My first mutant did NOT distinguish the hook row — removing the guard made an empty slice and blocked for an unrelated reason, so the row passed and looked proven. Only mutating to the actual pre-review shape showed it discriminates. Verified: `npm run lint:ci` exit 0. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com> * fix(#3802): measure the subject as git does — strip trailing whitespace, split CRLF git's cleanup=whitespace strips whitespace at BOTH ends of a line; the resolver handled only the leading direction, so a 72-char subject with trailing spaces measured 75 and stayed blocked — the defect class #3802 reports, surviving one round further (review of #3816, Major 2). The resolved subject now drops trailing spaces and tabs; the plain non- heredoc path is untouched, keeping the fix confined to heredoc resolution. The length-gate boundary rows gain dirty fixtures: 72+3 trailing spaces passes, 73+1 stays blocked on LENGTH. split('\n') left \r on every body line, so on CRLF input the delimiter never matched: the truncation guard was inert, an empty message resolved to 'EOF\r', and a real 72-char subject measured 73. Split on /\r?\n/ (Minor 3). The three property tests never reached the parser — the pinned-seed fc.string corpus contained no newline and no opener, so every property reduced to f(s) === s (Major 1). The generator now constructs heredoc- shaped input (all opener spellings, <<- tabs, optional terminator, CRLF) and each property asserts a floor on inputs its corpus actually resolved. All new rows proved failing-first against the pre-fix resolver. Also records the unquoted-delimiter expansion limit as one JSDoc sentence (Informational 5). Co-Authored-By: Claude Fable 5 <noreply@anthropic.com> * fix(#3802): close two recognition bypasses, pin the dquoted-delimiter limit Codex whole-PR review found two enforcement bypasses in the resolver: - The opener's path prefix was \S*, which accepted `id;/bin/cat` — the resolver then validated the heredoc BODY while bash runs `id` first and git's real subject is id's OUTPUT. The prefix is now a path-character class; any shell metacharacter fails recognition and the form falls back to the opener line and the format gate. - The blank-line skip used JavaScript trim(), whose Unicode whitespace class skips lines git KEEPS: a NBSP first body line resolved to the SECOND line while git's real subject is the NBSP line (verified against git stripspace — the c2a0 bytes survive). Blank is now git's ASCII space/tab only; a Unicode-blank line is returned and fails the format gate, the same fail-closed direction git takes. Both proven failing-first at resolver AND hook level. Also: the <<"TAG" spelling is recorded as a documented limit — the -m capture stops at the delimiter's own quote so the caller can never deliver it (fail closed; widening the capture would change every embedded-quote case) — with a hook-level row pinning the limit; and the derivation property no longer accepts '' unconditionally, only for heredoc-shaped input, so a conditional constant-'' regression can't satisfy the corpus floor unnoticed. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com> * fix(#3802): recognition whitespace is ASCII, and '' answers to the generator Codex round 2: the opener's \s accepted Unicode whitespace bash does not split on — $(<NBSP>/bin/cat was recognized here while bash reads <NBSP>/bin/cat as the executable NAME, so recognition claimed a substitution that does not run cat. Every whitespace position in the recognition is now [ \t], the same ASCII rule as the blank-line skip, proven failing-first. The derivation property's ''-acceptance now consults GENERATION-TIME metadata: the heredoc generator records whether it built an empty message (terminator reachable, all scanned lines ASCII-blank, <<- tab stripping accounted for), and '' is accepted exactly then — a resolver conditionally degrading to '' on non-empty heredocs now fails, closing the residual round-1 permissiveness without re-deriving resolver logic. The changeset no longer overstates the opener spellings: it names the capture-deliverable set and the documented <<"EOF" limit. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com> * fix(#3802): nothing after the terminator escapes measurement Round-3 BLOCKER: everything after the heredoc terminator was silently discarded, so `-m "$(cat <<'EOF'\nfeat: ok\nEOF\n) <200 a's>"` — one 200+ char real subject once bash substitutes — measured 8 chars and dodged COMMIT_SUBJECT_TOO_LONG, a hole the base did not have. The canonical idiom's tail is exactly one closing-paren line; any other tail now falls back to the opener line and the format gate, the pre-fix behaviour for the whole form. Proven failing-first at resolver and hook level, including the glued-text and second-substitution variants. Also from round 3: `cat<<'EOF'` (no space) is legal bash and now resolves — the token before << is still literally cat; the env-prefixed and option-terminated spellings join the JSDoc KNOWN LIMIT list instead (fail closed, modelling bash prefix words is cost with no reported user); the changeset states the embedded-quote truncation limit for the message body, not just the <<"EOF" spelling; the dquoted unit and hook rows now cross-reference each other; and the fast-check setup helper's docstring no longer claims property-file exclusivity. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com> * fix(#3802): glued text outside the closing quote must not shrink the measurement Codex on the round-3 guard: bash concatenates -m "$(…)"suffix into ONE argument, but the capture holds only the quoted part — so the resolver measured the heredoc body (8 chars) for a 200+ char real subject, a net-new length-gate bypass the base did not have (base measured the opener and blocked). When the closing quote is followed by anything but whitespace or end-of-command, the hook now skips the resolver and keeps the pre-fix first-line subject: the heredoc form fails the format gate exactly as on base, and the plain single-line form keeps base behavior unchanged — both pinned as differential rows, the glued-suffix row proven failing-first against the unguarded script. The property generator's ''-oracle now models the post-terminator guard it previously predated: expectEmpty requires the FIRST reachable terminator to be followed by the one canonical closing-paren line, so a resolver regressing to '' on a non-canonical tail (e.g. a body line that doubles as an early terminator) fails the derivation property instead of being blessed by stale metadata. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com> * chore: retrigger CI — the previous wave never started (Actions queue stall) Co-Authored-By: Claude Fable 5 <noreply@anthropic.com> * fix(#3802): only resolve a heredoc whose body bash does not rewrite Round-4 review found two net-new enforcement bypasses: commands the base hook blocked (exit 2) that this branch allowed (exit 0). Both reproduced as a base-vs-head differential against the real hook, not inferred. The predicate "may I resolve this?" was computed from the resolver's input string alone, while two of its determinants live outside that string: 1. WHICH -m quote arm produced the input. Inside -m '...' bash performs no command substitution, so $(cat <<'EOF' is literal text and git's real subject is the opener line. The resolver ran on both arms, so all four delimiter spellings went 2 -> 0 on the sq arm — reachable by the ordinary slip of typing ' for ". The hook now records MSG_QUOTE and gates the resolver on dq; sq keeps head -1, exact base parity. 2. WHETHER the delimiter suppresses expansion. Only <<'D', <<"D" and <<\D do; a bare <<D is expanded by bash before git sees it. Resolving the literal dodged the format gate (feat: $UNSET_VAR reaches git as feat:) and the length gate (feat: ${LONG} reaches it at any length). The opener regex now separates the backslash-quoted and bare alternatives and refuses the bare one — the same fail-closed rule the metacharacter, truncation and post-terminator guards already follow. A test row asserted exit 0 for a bare-delimiter body, so the suite defended the second bypass and the fix could not land without editing a test that read as intentional. That row and its two unit counterparts now assert the block, per RULESET.TESTS.delete-bad-tests. Two unrelated rows used <<-EOF to exercise tab stripping; they move to <<-'EOF' so each tests what it names. Scoping the adjacency guard to the matched arm — required by the fix above — also removes a spurious block (round-4 Minor 1): a double-quoted heredoc whose body mentioned a glued single-quoted token tripped the sq arm. The JSDoc claimed <<"EOF" was unreachable through the caller and that the bare-delimiter gap was pre-existing. Round 4 disproved both; both corrected here, along with the matching changeset sentence. Verified: 7 bypass commands now block at head (was allow), the #3802 fix and plain-form parity are unchanged across 8 control commands, hooks-opt-in 44/44, worktree-safety 401/401, property-test non-vacuity 73/200 against a floor of 20, lint:ci exit 0. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01EAbQy7n4mLMB7h3TnZ8GdG * fix(#3802): resolve only where the captured text is provably git's subject Codex review of the full PR found two more inputs where the validated text is not the subject git receives, both net-new bypasses (base 2 -> head 0), plus one escalation of round-4 Minor 2. All reproduced here against the real hook and confirmed against real commits before fixing. BLOCKER — the matched -m need not be git's message. The capture is a search over the whole command and the double-quoted arm runs first, so it could select a -m that is not the subject at all. git concatenates multiple -m values and takes the FIRST as the subject, so git commit -m 'WIP first' -m "$(cat <<'EOF' … )" commits the subject `WIP first` while the hook validated the heredoc. Same for an unquoted earlier -m, for a heredoc after `--` (a pathspec, not a message), and for one belonging to a later `&& echo`. The mis-selection is pre-existing; resolving it is what made it a bypass. The hook now resolves only when nothing before the matched -m could have been an earlier message, an end-of-options marker, or another command. BLOCKER — cleanup mode is part of the predicate. The resolver skips leading blank lines and strips trailing whitespace because git's DEFAULT cleanup=whitespace does. Under --cleanup=verbatim git does neither, so a 72-char subject plus three trailing spaces is committed at 75 bytes while the hook measured 72 — COMMIT_SUBJECT_TOO_LONG dodged. This one hides from `git log --pretty=%s`, which strips trailing whitespace in its own output; the raw commit object shows 75 vs 72. Any named mode other than whitespace, in either the --cleanup= or -c commit.cleanup= form, now refuses to resolve. MAJOR — recognition trusted any path ending in /cat, so a planted `../evil/cat` printing `WIP injected` had its heredoc body validated while git's real subject was `WIP injected`. Only a bare `cat` or an absolute path is recognised now. A bare `cat` shadowed on PATH is a documented residual and is not fixable from a string — nor a meaningful boundary, since planting an executable already allows running git directly. The changeset and the JSDoc both asserted that a `"` anywhere in the message blocks. Measured false: a `"` on a later body line resolves fine, because the subject completes before the truncation point; only a `"` in the subject line blocks. The changeset also listed <<"EOF" as covered when it measures 2/2. Both rewritten to claim only what is measured, and the residual false positives are now named. Verified: 4 + 2 + 3 new bypass commands now block, with non-vacuity controls proving the default path still resolves; all round-4 maintainer blockers stay closed; the #3802 fix and plain-form parity unchanged across 7 controls; hooks-opt-in 47/47, worktree-safety 402/402, property non-vacuity 73/200 against a floor of 20, lint:ci exit 0. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01EAbQy7n4mLMB7h3TnZ8GdG * fix(#3802): scope the cleanup-mode guard to the command outside the message The guard scanned the whole $CMD for `--cleanup=` / `commit.cleanup=`, and the heredoc BODY sits verbatim inside $CMD, so any conforming message that merely MENTIONED the token was refused, fell back to the opener line, and was blocked with CONVENTIONAL_COMMITS_VIOLATION. These are ordinary English in this repository, whose own hooks and docs discuss cleanup modes constantly. Reproduced against the real hook: `fix: document commit.cleanup=strip behavior` blocked, the same message without the token allowed (review of #3816, round 5 — BLOCKER). Scoping to $MSG_PREFIX alone, as prescribed, would have reopened the round-4 length-gate bypass the guard exists for: git accepts the flag on EITHER side of -m, and `git commit -m "<heredoc>" --cleanup=verbatim` is caught today only because the scan is command-wide. Measured, not assumed. The scan now covers MSG_PREFIX + MSG_SUFFIX — the whole command minus the one span that is message text — joined with a space so a token cannot be forged across the seam. Swept the guard class rather than the reported instance. The adjacency guard does not share the defect: an in-body `-m "foo"bar` is refused by the already-documented embedded-quote capture limit (any `"` in the subject line truncates the capture), and an in-body `-m ` without quotes resolves and is allowed. Deliberately untouched. Both directions pinned failing-first: the three false-positive rows red against the unscoped guard, and the trailing-flag row reds against prefix-only scoping. Each mutation was echoed back to prove it landed. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01XogDtuuuGQEfsWaLSaZCLB * fix(#3802): read commit options the way bash hands them to git Round 6 reported the adjacency guard scanning all of $CMD for a glued `-m "..."`, so a glued -m belonging to a chained-after command refused a heredoc that was never truncated. Glue is a property of the ONE character following the matched span, so that character is now the whole window. Separators and redirections are excluded because bash does not concatenate across them: in `-m "msg"&& echo hi` the argument ends at the quote, so there is no truncated capture to defend against. An independent full-PR pass then found three accept-direction defects this PR had introduced in earlier rounds, each measured against a real commit by reading the raw commit object — `git log --pretty=%s` strips the trailing whitespace that makes the length wrong and hides it: --cle=verbatim git accepts any unambiguous prefix of a long option, so the mode was set by a token that is not the literal --cleanup. 75-byte subject recorded, 72 measured. -am 'WIP first' git reads this as -a -m, so the real subject is `WIP first` and the heredoc is only the second message. The scan looked for a standalone -m. --clean""up=verbatim bash removes quotes before git sees the -""m argument, so a spliced spelling is the same option and matched no literal. The two option-name scans now read their window with quote characters removed, which is what bash does to it, and the cleanup class covers git's abbreviations. The adjacency test deliberately keeps the raw text: it asks about a literal character position, not an option name. Narrowing the cleanup window to git's own command segment was tried and reverted. `;`, `&` and `|` end a command only outside quotes, and this is a substring scan, not a parse: an unconditional trim cut the window short on `--author "a&b"`, and a quote-aware trim still cut it on `--author a\&b`. Each hid a real trailing --cleanup=verbatim and accepted a 75-byte subject. The resulting false positive — a --cleanup carried by a chained command refuses the commit — is documented and pinned instead. Refusing a commit git would take is recoverable; accepting an over-long subject is not. Sixteen rows in tests/hooks-opt-in.test.cjs. Seven mutations, including both reverted narrowings, so no dead end can be reintroduced silently. * fix(#3802): close six accept-direction bypasses in the resolve guards Round 7's FIRST-MESSAGE GUARD Major does not reproduce. Measured against the real hook in a complete tree at the reviewed head: the classifier gate runs before any guard, so `git add -A && git commit …` (git->add stops on a non-commit subcommand) and `cd dir && git commit …` (the first executable is not git) exit 0 without a guard being evaluated. The control is the proof — a subject the bare form blocks with CONVENTIONAL_COMMITS_VIOLATION exits 0 in both chained forms, so the hook never validated them and cannot be over-blocking them. The guard is unchanged; scoping this scan to $MSG_PREFIX alone is what reopened the round-4 trailing-flag bypass. The class was real, though, one shape further out: `FOO=bar; git commit …` IS classified and then refused, because assignment detection is prefix-anchored and the tokenizer does not split operators. Pinned as a counterexample and disclosed rather than generalised away; narrowing it means changing isGitSubcommand, the shared git-commit detector every gating hook uses, and it fails closed. Six accept-direction bypasses are fixed. Each let the hook resolve and ALLOW a commit whose real subject the rules refuse; the three that turn on git's recorded subject were confirmed against the RAW COMMIT OBJECT, since `git log --pretty=%s` strips trailing whitespace and hid two of them: --cleanup=whitespace -m <72+spaces> --cleanup=verbatim git kept 75 bytes -mWIP -m <heredoc> git recorded `WIP` --mes=WIP -m <heredoc> git recorded `WIP` -\m WIP -m <heredoc> git recorded `WIP` git commit --amend --no-edit \n echo -m <heredoc> echo's argument read --squash=HEAD -m <heredoc> `squash! …` Causes: one BASH_REMATCH inspected only the FIRST cleanup directive while git applies the last, so multiplicity now refuses rather than guesses at an argument order a substring scan cannot recover; the option scan required a trailing space or `=`, missing attached values and long-option abbreviations; dequoting removed quotes but not the syntactic backslashes bash also removes; the separator scan omitted newline; and --squash/--fixup have git compose the subject, so the supplied message is not the subject at all. Every fix widens refusal, the direction this file documents as recoverable. The multiplicity count first broke the hook outright: the script runs under `set -euo pipefail` and grep exits 1 when it matches nothing, which is the common case, so every ordinary commit died at exit 1 with no verdict. Guarded, and only caught because the probe runs the real hook rather than the scan. Five new rows, all five proven red against the pre-fix hook, each carrying a non-vacuity assertion that the canonical single-`-m` heredoc still resolves. Changeset corrected on three counts: "all fail-closed" was wrong (persistent commit.cleanup fails OPEN, as do the -C/-c/-F/-t message sources), "global options are all walked through" was too broad, and the chained-before claim now states what is measured. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_018FUAVz49BghqxoJgwt7EW9 * fix(#3802): stop the separator and glue classes matching a literal backslash Round 8's Major, with two corrections to its account. `;`, `&` and `|` are metacharacters inside `[[ ]]`, so an inline bracket class must escape each one. POSIX bracket expressions have no escape mechanism of their own, so on bash 3.2 -- the system /bin/bash on macOS, already a supported target here per the `declare -A` ban in tests/install.test.cjs -- those backslashes reach the regex engine and add a literal `\` to the class. bash 4+ consumes them, which is why this is invisible on a modern bash. The hazard is specific to bracket expressions: `\(` outside one is made literal correctly on every version, and the subject validator and the `-m` capture classes were checked and are unaffected. The prescribed fix is not taken, because it does not parse. Inline `[;&|]` is a bash SYNTAX ERROR on 3.2 and on 5.3 alike -- the backslashes exist to get the metacharacters past the `[[ ]]` parser, so removing them leaves an unparseable script. Each class is held in a variable and expanded unquoted on the right of `=~` instead, which is a plain regex on both versions. One root cause, consequences in BOTH directions. The reported half is the separator scan over-blocking. The half not reported is the accept direction, and it is the more serious: the glue class is NEGATED, so on bash 3.2 a backslash-glued suffix fell inside the exclusion and the hook RESOLVED a heredoc it should have declined -- measured exit 0 on 3.2 against the unfixed hook, exit 2 everywhere else, with a letter-glued control refused in all four cells. The reported repro is not actually fixed by this, and the changeset says so. A `\`-newline line continuation carries a literal newline, which the round-7 separator guard refuses on every bash, so that shape stays blocked with or without this change. Narrowing the newline guard is not attempted: telling a continuation from a separator by substring scan is the class that was tried twice in earlier rounds and reverted both times, and an escaped backslash sitting immediately before a real newline is indistinguishable from a continuation. Disclosed as a known fail-closed limit instead. Every new row runs under each bash on the machine. Against the unfixed hook both bash 3.2 rows go red while all four bash 5.3 rows stay green -- written the ordinary way these rows would run under PATH bash, pass against the broken hook, and prove nothing. Two non-vacuity controls per interpreter prove the validator is reached rather than passing everything. All 8 rows of the established differential harness are byte-identical before and after on both versions: no regression, no new refusal. * fix(#3802): remove the $ of a dollar-quote from the option-name scans Independent round-8 review, accept direction. The option-name windows are dequoted so they match "the command as bash hands it to git" -- round 6 removed quote characters, round 7 removed syntactic backslashes. Both passes missed that bash has two further quoting forms whose introducer is a `$`: `$'...'` and `$"..."`. Removing the quote characters alone left that `$` stranded INSIDE the option name, so `-$"m"` dequoted to `-$m` and matched no literal, while bash passed a real `-m` to git. Measured on bash 3.2.57 and 5.3.15 against a real repository: the hook allowed git commit --allow-empty -$"m" WIP -m "$(cat <<'EOF' fix: a perfectly ordinary conforming subject EOF )" with exit 0, and `git cat-file -p HEAD` recorded the subject `WIP`. The comparison that establishes this is HEAD-internal, not a differential: the same command spelled `-m WIP` is refused (exit 2). The merge-base refuses EVERY heredoc form, including a perfectly conforming one, so its exit 2 on this input says nothing about whether any guard fired -- it is the absence of the feature, not a working check. The same miss covered `$'m'`, spliced `--message`, `--cleanup`, `--squash` and `--fixup`. An option NAME finished by a command substitution -- `--clean$(printf up)=verbatim` -- is a different problem and gets its own guard: bash runs a program to complete the name, so the argv git receives is not derivable from this string at all, and resolution is refused rather than guessed. The guard is scoped to the NAME: the class is a `-`-leading token whose characters up to the substitution contain no `=`. A substitution supplying a VALUE -- the ordinary `--author="$(git config user.name)"`, spaced or glued, in either window -- is untouched and still resolves, pinned in both directions. It is a SHAPE, not a segmentation of the command line; segmenting was tried twice in earlier rounds and reverted both times, and that reasoning stands. Both new rows fail against the unfixed tree with their own assertions, proven in a complete worktree at the previous head rather than a hook copied out of its tree. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01TadqrpTE2m6gCB7CaNNLcy * fix(#3802): recognise a canonical cat, not any absolute path ending in /cat Independent round-8 review, accept direction. Round 4 restricted heredoc-opener recognition to an absolute path, after a relative `./cat` was measured being trusted to echo its stdin. It stopped at "absolute", so any absolute path ENDING in `/cat` was still trusted -- the same claim the round-4 reasoning had rejected one spelling earlier. Measured on bash 3.2.57 and 5.3.15 against a real commit: with an executable at `/.../fake-cat/cat` printing `WIP injected`, the hook validated the conforming heredoc body and allowed the commit (exit 0) while `git cat-file -p HEAD` recorded the subject `WIP injected`. The same command through `./cat` was already refused, which is the control that shows this is the round-4 class one spelling out rather than a new one. Recognition is now the canonical system locations -- bare `cat`, `/bin/cat`, `/usr/bin/cat` -- which is the only identity claim a string can support. `/usr/local/bin` is deliberately excluded: it is user-writable on ordinary machines, which is the plantable case this guard exists for. Anything else falls back to the opener line and the format gate: fail closed, exactly the pre-fix behaviour for the form. The pre-existing residual is unchanged and still documented: a bare `cat` shadowed earlier on PATH is indistinguishable here, and is not a meaningful boundary -- anyone able to plant an executable on PATH can run `git commit` directly. This hook stays an authoring guard, not a security control. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01TadqrpTE2m6gCB7CaNNLcy * fix(#3802): an option name carrying a shell expansion is unresolvable Independent review, round 9, accept direction. Four more spellings, and a change of strategy that is the actual point of this commit. Rounds 6, 7 and 8 each tried to EMULATE what bash does to an argument before git sees it -- round 6 removed quote characters, round 7 syntactic backslashes, round 8 the `$` that introduces a dollar-quote -- and each round review found another transform that had been missed. Round 9 found four more. All measured on bash 3.2.57 and 5.3.15 against a real repository, each with the plain spelling of the same command as its control (refused, exit 2) and `git cat-file -p HEAD` for the subject git actually recorded: -$'\155' WIP hook 0, real subject `WIP` ANSI-C octal -> m -$'\x6d' WIP hook 0, real subject `WIP` ANSI-C hex -> m -`printf m` WIP hook 0, real subject `WIP` backtick substitution x= … -${x}m WIP hook 0, real subject `WIP` parameter expansion -? WIP hook 0, real subject `WIP` pathname expansion and the same class through the cleanup guard, where git recorded a 75-character subject the length gate had measured as 72: --cle$'\141'nup=verbatim, --clean`printf up`=verbatim, --cle?nup=verbatim The last two settle it. An option name finished by a PARAMETER expansion depends on a variable's value at run time; one finished by a PATHNAME expansion depends on the contents of the working directory. Neither is derivable from the command string at any level of effort, so emulation cannot be completed -- not "has not been completed yet". A fifth patch in that direction would have the same shape as the previous four. The rule is therefore no longer "normalise it and match the literal". It is: an option NAME carrying a shell expansion or quoting construct is UNRESOLVABLE, and unresolvable refuses. One rule covers every spelling above and every spelling nobody has thought of yet, in the fail-closed direction. The dequoting passes are kept rather than replaced: they still normalise the deterministic removals, so the guards RECOGNISE `--clean""up=` and `-\m` as the options they are instead of merely refusing them, which keeps the existing rows meaningful. Scope is unchanged and still pinned in both directions: the class is a `-`-leading token whose characters up to the construct contain no `=`, so a construct supplying a VALUE -- `--author="$(git config user.name)"`, the backtick spelling, `--date="${NOW}"`, a glob character inside an author string, a pathspec after `--` -- still resolves. Nine such forms are asserted to pass beside the seven that must refuse. The class is bracket-only and holds no backslash, per round 8: a POSIX bracket expression has no escape mechanism, and a backslash written inside one becomes a literal member on bash 3.2. The new rows fail against the previous head with their own assertion message, in a complete worktree with the lib built, not a copied hook. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01TadqrpTE2m6gCB7CaNNLcy * docs(#3802): disclose and pin the two spellings the round-9 class over-blocks A scoped review of the round-9 class asked one question -- does it refuse a conforming heredoc commit that the previous head accepted -- and found two spellings that it does. Both measured on bash 3.2.57 and 5.3.15, previous head 518d97b64 exit 0, current head exit 2: git commit -S$SIGNING_KEY -m <conforming heredoc> git commit -m <conforming heredoc> -- -*.txt Disclosed and pinned rather than narrowed, for two reasons. Narrowing is not available cheaply. Dropping the bare `$` member reopens `-$xm`: with `xm=m` bash hands git a real `-m`, which is the parameter expansion bypass the round-9 commit exists to close. Skipping tokens after `--` means deciding where git's options end from a substring scan, which is the class this file has already reverted twice for opening accept-direction holes -- a `--` inside a quoted value (`--author "a -- b"`) would truncate the window and hide a real trailing directive. And the limits are narrower than they look, because in both cases the spelling a developer actually reaches for still resolves: -S "$KEY" and --gpg-sign="$KEY" resolve '-*.txt', "-*.txt", ':(exclude)-*.txt' resolve The pathspec one is worth stating precisely: a glob only reaches git AS a pathspec when it is quoted, because an unquoted one is expanded by the shell before git is executed. So the refused spelling is not passing a glob to git at all, and the spellings that do are unaffected. Refusing a commit git would take is the recoverable direction; accepting a non-conforming subject is not. That is the trade this file already makes everywhere else, and it is made explicitly here. Nine rows pin the working spellings beside the three that refuse, so a later narrowing cannot silently drop the cases that must keep working. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01TadqrpTE2m6gCB7CaNNLcy * fix(#3802): join backslash-newline continuations before the resolve guards Round 9's Major, with a correction to its diagnosis. The cited bracket classes at :223 and :260 no longer exist -- round 8 moved both into SEP_CLASS and GLUE_CLASS, and a lone backslash before -m resolves (exit 0) at the reviewed head on both bash 3.2.57 and 5.3.15. What refuses the repro is the NEWLINE a `\`-continuation carries: round 7's separator guard reads any newline in a window as a command boundary, and `git commit \` newline ` -m "$(cat <<'EOF' …` was refused for that reason. Round 8 disclosed it as a fail-closed limit; round 9 calls the idiom common and the limit a Major, and it is fixed here. It was left as a limit because "is this newline a continuation" looked like the segmentation question this file has reverted twice. It is not: bash's rule is local and character-level. A newline preceded by an ODD run of backslashes is a continuation and bash removes both; an EVEN run (`\\` then newline) is a literal backslash followed by a real newline, which IS a separator. Both scan windows are joined that way immediately after they are cut from the command and before any dequote copy is derived, in three bash-3.2-safe parameter expansions: every `\\` pair is parked on \x01, any backslash-newline that remains is a lone one and is removed, then the pairs are restored. Measured on both bashes, both directions: git commit \<nl> -m <heredoc> 2 -> 0 the fix git commit \\<nl> -m <heredoc> 2 -> 2 literal \ + real separator git commit<nl> -m <heredoc> 2 -> 2 bare newline -m <heredoc>\<nl>suffix 2 -> 2 bash glues it; the glue guard sees it glued git commit … \<nl> --allow-empty<nl>echo -m … 2 -> 2 the REAL newline still separates The prescribed `[\;&|]` is not taken: a backslash written inside a bracket expression becomes a literal member on bash 3.2, which is the round-8 defect from the other side. Rows run under each bash on the machine. The fix row fails against the previous head in a complete worktree with the lib built; the four control rows were measured against that same head and were already refused, so they pin existing behaviour rather than the change. Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01TadqrpTE2m6gCB7CaNNLcy --------- Co-authored-by: Claude Opus 5 (1M context) <noreply@anthropic.com> Co-authored-by: Tom Boucher <trekkie@nomorestars.com>
8.9 KiB
8.9 KiB
type, pr
| type | pr |
|---|---|
| Fixed | 3816 |
The commit-message hook no longer blocks every heredoc-form commit — with hooks.community: true, gsd-validate-commit.sh rejected git commit -m "$(cat <<'EOF' … EOF)" with CONVENTIONAL_COMMITS_VIOLATION whatever the message said, because its -m capture matches across newlines and the message's first line was the literal $(cat <<'EOF' rather than the subject. That opener is a standard agent-authored commit idiom, so enabling the toggle — which also carries the session-state and phase-boundary hooks — made that pattern fail every time.
The subject is now resolved from the captured message before validation, for the canonical form: a single -m "…" holding one $(cat …) substitution, under git's default cleanup=whitespace. Resolution handles the delimiter spellings bash does not expand (<<'EOF' and <<\EOF, with or without <<-, spaced or space-free), the leading tabs <<- strips, CRLF line endings, and both directions of cleanup=whitespace — leading blank lines are skipped, and trailing whitespace on the subject is not counted against the 72-character limit.
Everywhere the validated text could differ from the subject git actually receives, resolution is refused and the commit stays blocked exactly as it was before this change. That covers: a -m '…' single-quoted argument, in which bash performs no command substitution at all; a bare <<EOF delimiter, whose body bash expands; a -m that is not git's first message argument, since git concatenates multiple -m values and takes the first as the subject; an explicit --cleanup= or -c commit.cleanup= mode other than whitespace, including git's
abbreviated spellings of it (--cle=verbatim and anything else that is an unambiguous prefix);
a message argument claimed by a bundled short option, since git reads -am 'first' as -a -m and
takes that first message as the subject; a cat reached by anything but a canonical system path (cat, /bin/cat, /usr/bin/cat), since an arbitrary executable merely named cat is not known to echo its stdin; a substitution composed with more text on either side of the terminator; and a " inside the subject line itself, which the quote-bounded capture cannot span.
Option names are handled in two layers, because trying to reproduce bash's argument processing
by itself does not terminate. The first layer normalises the removals that are deterministic —
quote characters, syntactic backslashes, and the $ that introduces a dollar-quote — so a spliced
spelling like --clean""up=verbatim, -""m, --clean\up=verbatim, -\m, -$"m" or
--mes$'sage'=WIP is recognised as the option it actually is rather than slipping past a literal
match.
The second layer is the general rule, and it is what the guarantee rests on: an option NAME
carrying a shell expansion or quoting construct is unresolvable, and unresolvable refuses. A
name finished by a command substitution in either spelling (--clean$(printf up)=verbatim,
--clean`printf up`=verbatim), by an ANSI-C escape (-$'\155', -$'\x6d'), by a parameter
expansion (-${x}m), or by a pathname expansion (-? where a file named -m exists) does not
resolve. The last two are the reason the rule is framed this way rather than as a longer list of
removals: a parameter expansion depends on a variable's value at run time and a pathname expansion
on the contents of the working directory, so neither is derivable from the command text at all.
The scope is the NAME — a construct supplying a VALUE, as in the ordinary
--author="$(git config user.name)", is unaffected and still resolves. A message option is also recognised when its value is attached (-mWIP,
which git reads as -m WIP) and when its name is abbreviated (--mes=WIP), and a newline is
treated as a command separator alongside ;, & and |, so a later command's -m is never
mistaken for this commit's message. Where more than one cleanup directive appears, resolution
is refused rather than guessed: git applies the last one, and argument order is not recoverable
from a substring scan. Modes in which git composes the subject itself (--squash, --fixup)
refuse resolution outright, because the supplied message is not the subject in them at all.
A \-newline line continuation — git commit \ then -m … on the next line — is joined before any scan runs, the way bash joins it: a newline preceded by an odd run of backslashes is a continuation and both are removed, while an even run is a literal backslash followed by a real newline, which stays a separator and still refuses. So the ordinary multi-line invocation resolves, and a continuation glued to the closing quote is seen as the glue bash makes of it.
Whether text is glued to the message argument is judged against the one character that
follows it, so a glued -m belonging to a command chained after this one no longer
refuses a message that was never truncated.
The character classes those scans use are held in variables rather than written inline. Inline,
each of ;, & and | needs a backslash to get past the [[ ]] parser, and a POSIX bracket
expression has no escape mechanism of its own — so on bash 3.2, the system /bin/bash on macOS,
those backslashes reach the regex engine and add a literal \ to the class. One cause, both
directions: the separator scan refused a conforming commit whose pre--m text merely contained a
backslash, and the glue scan, whose class is negated, resolved a heredoc whose suffix was glued
with a backslash rather than declining it. The second is the fail-open direction and is the reason
this is fixed rather than documented. Every row covering it runs under each bash on the machine,
because a row run only under bash 4+ — where the shell consumes the backslashes and the classes are
already correct — passes with or without the fix.
Known limits that fail closed — the commit is blocked, never wrongly allowed: an attached short-option value that begins with an expansion (-S$KEY, -S"$KEY") is refused, though the detached -S "$KEY" and the long --gpg-sign="$KEY" both resolve; an UNQUOTED dash-leading glob after -- (-- -*.txt) is refused, though every spelling that actually passes a glob to git as a pathspec — '-*.txt', "-*.txt", ':(exclude)-*.txt' — resolves, because an unquoted glob is expanded by the shell before git sees it; the <<"EOF" delimiter spelling and a closing ) on its own line remain false positives; a --cleanup= carried by a command chained after the commit refuses it as though it were git's own; and a leading assignment followed by a separator, as in FOO=bar; git commit …, is read as an assignment prefix, so the commit is recognised and then refused for the separator in its prefix. Which argument the hook captures as the message is unchanged.
Two limits fail OPEN, and are called out separately because they are the direction that matters:
a cleanup mode set persistently in git config is invisible to the hook, so under
commit.cleanup=verbatim a subject whose trailing whitespace pushes it past 72 characters is
measured without that whitespace and allowed; and the other options that supply a message from
somewhere other than -m (-C/--reuse-message, -c/--reedit-message, -F/--file,
-t/--template) are not detected. The latter is deliberate rather than overlooked: -c is
also a git GLOBAL option that legally precedes the subcommand, so scanning for it would refuse
ordinary git -c key=value commit invocations, and guessing that trade seemed worse than
naming the gap.
One limit is pre-existing rather than introduced here, and runs in the fail-open direction: the
hook validates a command only when the git invocation itself begins it. Leading environment
assignments, an absolute path to git, and the git global options this classifier knows are all
walked through — that set is finite and does not cover every global option git accepts, so an
unlisted one such as --config-env is not walked. Measured: git add -A && git commit …,
cd dir && git commit …, git status; git commit … and (git commit …) are not recognised as
commits at all, so they are unchecked in every message form, heredoc or not, while a command
chained after the commit (git commit … && echo done) is recognised normally. It is not true
of every chained-before shape, though: FOO=bar; git commit … tokenizes with FOO=bar; read as
an assignment prefix, so it IS recognised and then refused, which is the fail-closed limit noted
above. So the resolution and the limits here describe the commands this hook gates, not every
commit a shell can run. Widening the classifier is a separate change with its own bypass surface
and with blast radius beyond this hook — isGitSubcommand is the shared git-commit detector for
every hook that gates on one — so it is deliberately not made here. The two shapes above are
pinned by tests, including non-conforming subjects that prove they are unvalidated rather than
merely permitted. (#3802)