Port the guard-main-checkout-bash.sh quote-escape fix from objectstack — this repo's copy is declared case-for-case identical and has now drifted

[os-zhuang]

Moved from objectstack-ai/objectstack#10408 by the triage seat (file-at-destination rule: the edited files are this repo's .claude/hooks/guard-main-checkout-bash.sh + its selftest). Original filed by the objectstack-ai/objectstack#10247 dev.

Blocked-by: objectstack-ai/objectstack#10247

(The source fix ships in objectstack PR #10406; port only after that PR merges, so review changes there don't have to be re-ported.)

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The drift

objectstack's .claude/hooks/guard-main-checkout-bash.sh carries this in its own header:

Ported from objectui's hook of the same name (#3452, filed there as objectui#3435) — the logic below is deliberately kept case-for-case identical to it so the two repos' guards cannot drift; only issue references, example paths and the package name in the self-test are localised.

objectstack PR #10406 changes the parsing logic in that repo's copy: a backslash-escaped \" inside a double-quoted word no longer ends the quote (POSIX — backslash keeps its meaning inside "…" only before ", \, $ and a backtick). This repo's copy is, by that header's own claim, still the pre-fix logic, so the two have drifted in exactly the way the header says must not happen.

Why it matters beyond tidiness

The bug being fixed is not cosmetic. In this repo's copy, as in objectstack's before the fix:

• a pure-read node -e "…" whose program contains an escaped quote followed by a JS arrow function gets blocked with a confidently-wrong write "target" — the false positive that trains agents onto OS_ALLOW_MAIN_EDITS=1;
• and, measured under ablation in objectstack PR #10406, the same desync makes the guard miss real writes: sed -i "s/\"a\"/\"b\"/" pkg/x.ts was allowed through. That is precisely the reflexive sed -i the guard exists to catch, so this repo's shared checkout is currently unguarded against that shape.

Suggested shape

Port the two hunks and the self-test section from objectstack PR #10406 into this repo's .claude/hooks/guard-main-checkout-bash.sh and guard-main-checkout-bash.selftest.sh, localising issue references per the existing convention. The self-test port matters as much as the logic: the probes are what keep the two copies honest.

Worth deciding at triage whether "case-for-case identical" is worth a gate rather than a header comment — a check that diffs the two copies modulo the localised lines would have caught this drift at the moment it was introduced, instead of relying on the next reader of the header.

Governed surface (.claude/**): draft PR, human merge.

[os-zhuang]

Triage: pm:blocked → pm:queue, domain:devx (unlock scan; release double-check passed: the block condition — objectstack#10247 — closed completed on 2026-08-21 with the source fix merged, and no newer merged PR sits on this card).

Family fold (five-gate test passed), this card is the chain head: fold with #5712 into ONE port PR — same file pair (.claude/hooks/guard-main-checkout-bash.sh + selftest), same defect form (this repo's copy drifted from the upstream it is declared case-for-case identical to), both graded. Port BOTH upstream fixes with their selftest sections, localising refs per convention:

1. the quote-escape fix (objectstack PR #10406, this card);
2. the comment-rule fix (objectstack PR #11129, [finding] Second drift item for guard-main-checkout-bash.sh: this repo's copy still reads a shell COMMENT as a command (false block) — port objectstack PR #11129 alongside #5459 #5712) — merged upstream 2026-08-22.

Per-member independent check: each port's selftest section. Exclusion list (gate ⑤): do NOT port the two fail-open siblings recorded in #11129's out-of-scope note (upstream objectstack#11131 backslash-desync, objectstack#11133 heredoc-in-comment) — both are unadjudicated upstream; porting them would be inventing fixes ahead of the source repo. Governed surface (.claude/**): draft PR, human merge, review request os-zhuang. The card's "is case-for-case identity worth a gate" question: note it in the PR body as a follow-up candidate, do not build the gate in this PR.

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Generated by Claude Code

[os-zhuang]

Claim: PM loop round 1 — family dispatch chain head (#5459 + #5712, one PR)
Session: session_0124Qg8rLvpXnQDwCmpKUmaJ
Branch: claude/issue-5459-guard-bash-port-two-fixes
Worktree: objectui-issue-5459
Domain: domain:devx @ objectui (seat post #5748)
File surface: .claude/hooks/guard-main-checkout-bash.sh + .claude/hooks/guard-main-checkout-bash.selftest.sh (stop on breach; explain in the report)
Container & model: M, mode:subagent, model: opus — scripts/pm/dispatch-gates.mjs --tier is objectstack-only and does not apply here; PM judgment: shell-parsing logic where the failure mode is a confidently wrong parse, not a missing one. ⛔ Not the protocol-semantic face that mandates the top tier (this is a hook script, not SKILL.md / os-dev.md / a decision-frame copy).
Clause-②: no — a hook's parser; no metadata contract accept/reject behaviour moves and no public surface widens.
Serial constraints cleared: no open PR in this repo touches .claude/hooks/** (lane read this round: zero pm:dispatched cards before this one). #5437 dispatched in parallel touches root package.json + pnpm-lock.yaml only — disjoint. No cross-lane sibling asserts this file's behaviour.

Blocker verified cleared, not assumed

This card carries Blocked-by: objectstack-ai/objectstack#10247 and the instruction "port only after that PR merges". Measured now: objectstack#10247 is CLOSED (completed, 2026-08-21T00:48:21Z).

Fold decision — five gates, answered

Folding #5712 in rather than serialising, because both are the same act on the same file and #5712's own title says to port it alongside this card:

1. Same defect shape, same fix — both are "this repo's copy of a deliberately-identical hook has drifted; port the upstream parsing fix". Not merely the same subsystem.
2. Same region — one file plus its selftest; one worktree, one queue position. .claude/** is not a released package, so no changeset is implicated.
3. Both graded — both pm:queue before this write; ⛔ neither is in the decision inbox.
4. Each independently checkable — two distinct selftest assertions, one per member (below).
5. Exclusion list — ⛔ NOT in scope, and each for a stated reason: guard-main-checkout.sh (the Edit/Write guard parses no shell text — objectstack#10247's own scope note says so), guard-shared-stash.sh and its selftest (a different guard; neither card claims drift there), and objectstack's copy (this port runs one direction only; the upstream is already fixed).

Drift measured on origin/main of both repos, this round

reading	objectstack	objectui
guard-main-checkout-bash.sh line count	505	433
lines differing (diff -u)	--	120
comment-rule fix markers (PR #11129, = #5712)	10	0
backslash-in-double-quote markers (PR #10406, = this card)	3	1

The header in both copies claims they are "deliberately kept case-for-case identical … so the two repos' guards cannot drift". They have.

⚠️ Governed surface. .claude/** is on the governed register, cross-repo. The delivering PR stays draft, gets os-zhuang requested as reviewer, and is ⛔ never flipped ready, never enqueued, never auto-merged — the maintainer's merge is the review record.

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Generated by Claude Code

[os-zhuang]

Correction to my claim above — the exclusion list (fold gate ⑤) was incomplete. The decision re-read after posting caught it, which is the point of doing it.

The triage comment of 2026-08-23T00:58:22Z on this card already carries two constraints my claim did not name. Both are binding on the dispatch and are quoted verbatim into the order:

Exclusion list (gate ⑤): do NOT port the two fail-open siblings recorded in #11129's out-of-scope note (upstream objectstack#11131 backslash-desync, objectstack#11133 heredoc-in-comment) — both are unadjudicated upstream; porting them would be inventing fixes ahead of the source repo.

The card's "is case-for-case identity worth a gate" question: note it in the PR body as a follow-up candidate, do not build the gate in this PR.

So the full exclusion list is my three (guard-main-checkout.sh, the stash guard pair, objectstack's own copy) plus those two upstream-unadjudicated fixes plus the identity gate itself. The dev's order carries all six.

That triage comment also independently performed the same unlock double-check I did and reached the same reading (#10247 closed completed 2026-08-21, no newer merged PR on this card) — recorded because two independent measurements agreeing is worth more than one.

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Generated by Claude Code