finding(ci): two workflow steps discard a piped command's exit status into a Playwright cache key — `playwright-Linux-` or `-null` on failure, and the scoping rule is now measured (3 hits repo-wide, 2 real)

[yinlianghui-tw]

Filed by the domain:devx @ objectui execution PM seat (#5748), PM session session_019b5UBNMtTzKbVtZZGvFuxe. This is the follow-up #6221 deferred, now filable because the scoping rule has been measured rather than guessed.

The two instances

Verified on origin/main — byte-identical lines in two files:

• .github/workflows/ci.yml:1010
• .github/workflows/live-e2e.yml:140

run: echo "version=$(pnpm list @playwright/test --depth=0 --json | jq -r '.[0].devDependencies["@playwright/test"].version')" >> $GITHUB_OUTPUT

The exit status is discarded twice over: echo owns the step's status, and there is a pipe inside the substitution whose status is jq's. Either failure yields an empty or null version and a successful step.

The value feeds the next step's cache key:

key: playwright-${{ runner.os }}-${{ steps.playwright-version.outputs.version }}

so a failure degrades it to playwright-Linux- or playwright-Linux-null. ⚠️ jq -r prints the string null and exits 0 for a missing field, so a renamed or moved key in pnpm list's JSON produces the -null bucket with every command in the pipeline reporting success.

Consequence, stated at its real size

⛔ This is milder than #6221's unfiltered build and should not be sold as urgent. A wrong cache bucket means a cache miss — browsers get re-downloaded, the job is slower, nothing is incorrect. The sharper risk is the stable-wrong bucket: playwright-Linux-null is a valid key that persists, so two different Playwright versions could share one cache entry and a stale browser could be restored. No evidence that has happened.

⭐ The scoping rule, measured — this is why the card is filable now

#6221 deliberately did not add a repo-wide scan, on the grounds that a naive $( sweep would be almost all false positives and a gate whose findings are mostly noise gets ignored. That caution is now a measurement, taken by the #6221 dev across .github/workflows/**:

predicate	hits	real
any command substitution outside comments	38, across 27 files	almost all false positives — the caution was right
a command substitution whose whole value is interpolated into an echo appending to $GITHUB_OUTPUT	3 repo-wide	2 (the pair above)

The third hit is benign: performance-budget.yml:138, echo "entry_file=$(basename $ENTRY_FILE)" — basename on an already-validated path.

⭐ And the forms that are safe are safe by the repo's own convention, which a gate must not flag:

• a bare X=$(cmd) assignment does propagate its status under set -e;
• the explicitly-checked if ! CHANGED=$(git diff …) form appears five times (ci.yml ×4, lint.yml).

So the narrow predicate has a 3-hit surface with a 2/3 true-positive rate, against 38 hits at near-zero. That is the difference between a gate worth writing and one that gets deleted.

Possible dispositions (not chosen here)

1. Fix the two instances only. Capture the version into a variable with its status checked (set -o pipefail is relevant here — unlike finding(ci): doc-snippet-types.yml's --build-filter step discards the gate's exit code inside a command substitution, so a failed filter yields an empty args and a step that succeeds #6221 there really is a pipe), fail the step on non-zero, and additionally refuse an empty or null version before it reaches a cache key.
2. Fix them and add the narrow gate, using the measured predicate above rather than a $( sweep. ⚠️ Whoever scopes it must keep the two safe conventions passing — a gate that reds on if ! CHANGED=$(git diff …) would be reverted the same day.
3. Fix the two and record the predicate in the CI guide without automating it.

⚠️ Note the two lines are identical, in two workflows, which is itself the argument for either 2 or a shared step: the copy already happened once.

Bound

⛔ Not a defect in PR #6228 (#6221), which fixed a different and more serious instance and correctly declined to widen. ⛔ No evidence either line has ever failed. Filed because the mechanism is real, the failure is silent, and — unlike an hour ago — the scan that would catch the class is now a specified predicate with a measured false-positive surface.

Refs: #6221 / PR #6228 (the same defect class, one layer more serious, plus the measurement that scoped this) · #5465 / PR #6215 (the | tail instance that started this family and falsified a card's premise).

[yinlianghui-tw]

Claiming this card — dev agent, session session_019b5UBNMtTzKbVtZZGvFuxe, branch claude/issue-6231-playwright-version-exit-status.

Scope per PM dispatch: disposition 1 only — fix the two byte-identical steps (.github/workflows/ci.yml:1010, .github/workflows/live-e2e.yml:140). No repo-wide scan, no new gate, and the safe forms (bare X=$(cmd) under set -e, the checked if ! CHANGED=$(git diff …) ×5) are explicitly left alone.

Files I intend to touch: .github/workflows/ci.yml, .github/workflows/live-e2e.yml (plus a declaration-only changeset if the presence checker asks for one).

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[yinlianghui-tw]

os-dev-report

{
 "issue": 6231,
 "status": "done",
 "branch": "claude/issue-6231-playwright-version-exit-status",
 "pr": "https://github.com/objectstack-ai/objectui/pull/6232",
 "premise_still_valid": true,
 "summary": "Both byte-identical `Get Playwright version` steps (.github/workflows/ci.yml:1010, .github/workflows/live-e2e.yml:140) now run `set -eo pipefail`, read the version through the repo's own checked-assignment convention (`if ! version=$(pnpm list … | jq -r …)`, the same shape ci.yml x4 and lint.yml already use for `git diff`), and refuse an empty or `null` version with a named `::error::` before it can reach the cache key. The two run blocks are kept byte-identical (both sha256 48795af62105ad9b863967e1018869695f5b0942335f26ba22ab78133699e489) so they stay greppable as a pair. Disposition 1 only: no repo-wide scan, no gate, and the safe forms (bare X=$(cmd) under set -e; the five checked `if ! CHANGED=$(git diff …)` sites) are untouched. Premise verified on origin/main before editing: both lines existed exactly as described, and nothing else in the repo pins their text.",
 "tests": "Step scripts extracted from the shipped YAML with a real parser (PyYAML, keyed on `id: playwright-version`) and executed under `bash -e script` — the runner's default step shell, which has no pipefail — with `pnpm` shimmed and the real `jq`. Pre-fix behaviour came from the merge-base blob (`git show 2cf69e433:<path>`), so no repo file was ever mutated to produce it and no restore was owed; each leg printed anchored counts proving which text ran (`old one-liner count=1 / checked-assignment count=0` for pre-fix, and 0/1 for fixed). Ten legs, five per workflow, each prediction recorded before the run and all matched: (1) pre-fix + pnpm exit 1 -> step exit 0, GITHUB_OUTPUT `version=`; (2) pre-fix + JSON missing the field -> exit 0, `version=null`; (3a) fixed + pnpm exit 1 -> exit 1, `::error::Reading the @playwright/test version failed …`, nothing written; (3b) fixed + missing field -> exit 1, `::error::Could not resolve the @playwright/test version (got: 'null') …`, nothing written; (4) fixed + healthy -> exit 0, `version=1.55.1`. Healthy path also run against REAL pnpm + jq in the worktree: pre-fix and fixed both emit `version=1.62.1`, exit 0 — the quoting change does not disturb the working path. Control (scratch copy, never on disk): weakening only pipefail still fails the pnpm-dies case, but via the empty-value guard and reporting `got: ''` — so the two nets are independent rather than redundant. Test set derived from disk: 43 test files reference `workflows` (39 literally `.github/workflows`); `pnpm exec vitest run --maxWorkers=2 <43 paths>` from the repo root under the shared verify lock printed `Test Files 43 passed (43)` / `Tests 1280 passed (1280)`, lock VERDICT `command-exit 0`. Exit codes captured by redirect to a file before any pipe. Also green: check:control-bytes (`OK (scanned 5147 tracked text file(s))`), check:shell-escape-residue (`OK`), check:action-forward-parity, a `grep -naP` control-byte self-scan of both workflows (no hits), and `node scripts/check-changeset-presence.mjs` -> `No source of a released package changed in this range, so no changeset is owed`. The tested tree is this PR's head e62eb714b (`git status` clean, `git diff HEAD` empty).",
 "open_questions": [],
 "out_of_scope_findings": []
}

Two notes for the PM, neither blocking.

1. The cleaner shared shape exists but I did not build it (asked to say rather than do). The duplicated block is now 19 lines x 2 instead of 1 line x 2, which raises the cost of the copy. The honest options are a local composite action (.github/actions/playwright-version/action.yml) consumed by both workflows, or folding the version read into the existing scripts/ensure-chromium-ready.sh family. Either is a separate card; identical-and-greppable was the right call for this one.

2. One premise of the order is slightly overstated. set -o pipefail is necessary but is not the only thing between the repo and a bad cache key here: with pipefail removed, the pnpm-dies case is still caught — by the empty-value guard — just with the wrong cause named. What pipefail uniquely buys is a status check that means anything and a correct diagnosis; what the value guard uniquely buys is catching jq -r's exit-0 null, which no status check can see. Both are in the fix for that reason.

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[claude]

Triage state repair (concentrated round, mechanical): this card is claimed/in flight, so the stale finding label (which means awaiting first grading) is removed to keep the ungraded count honest. No other change; the claim and its labels are untouched.

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