The repo's gates were not pinned to their wiring. Deleting the
check-skill-version-bump block from .pre-commit-config.yaml left the
whole suite green; deleting eight blocks at once, run-tests among them,
also left it green. Only 4 of 20 hook ids had their wiring pinned
anywhere, so a merge conflict resolved badly could stop the suite
running at pre-push forever while every test still reported green.
test-adr0020-contract now derives the repo-authored hooks from the
repo: local entries and pins each one's id, entry and stages against an
explicit expected set, both directions, with the same non-vacuity
guards the file already applies to its own fixtures. Upstream hooks and
their rev: values are untouched, so a rev bump does not churn the test.
Mutation-checked: a removed block, a repointed entry and a hook moved
off pre-push each go red; a rev bump, a comment edit and reordering
stay green. 29 -> 44 assertions.
run-bats computed each file's TAP plan and then discarded it, so a
process printing "1..10", three ok lines and exit 0 was counted as
"3 tests, 0 failures" with seven tests silently gone. That is exactly
the wrapper-swallows-the-status case the runner's own comment puts in
its threat model, and the plan was the only surviving signal. The plan
is now enforced in both directions when a file emits exactly one.
Also: test-no-pipefail-early-exit-grep's live-tree floor goes from 20 to
50 against an actual 57, matching test-vale-wrap's per-glob discipline,
and test-vale-wrap's header names the real path to vale-wrap.sh.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01NwD8Egs5r4ndqeFLmhusX2
Why
Two suites failed intermittently — tests/test-vale-wrap.sh case 21 and
tests/test-check-release-needed.sh cases 4 and 15 — on correct output, and never
when run alone. The cause is the `echo "$OUT" | grep -q P` idiom under
`set -o pipefail`: grep -q exits as soon as it has an answer, bash's echo can
hand a multi-line value to the pipe one line at a time, and a write after the
reader is gone kills echo with SIGPIPE. pipefail then reports the writer's
death, so output that DID match reads as "no match". Every observed failure had
lines after its match; case 15's match is on line 1 of 6, the widest window in
that file.
Forced with a pause before the writer's last line, the pipe form failed 50 of 50
runs; a here-string, a match on the last line, and the same pipe without
pipefail each passed 50 of 50. Unforced the rate is about 1 per 670 suite runs,
which is why it read as a flaky gate rather than a bug.
The failures at review time are consistent with this, but were not proven to be
it: the suite was running while agents edited live config files in place, and a
brief change to .vale.ini or .pre-commit-hooks.yaml would produce the same two
failures. The race is real and fixed either way.
Implementation Notes
`grep -q P <<< "$VAR"` has no separate writer process, so there is nothing to
race. It is not a retry or a sleep. 121 sites converted across 9 files, three of
them scripts rather than tests: new-agent.sh, new-skill.sh and
check-executables-allow-sync.sh. None ships via .pre-commit-hooks.yaml, so no
external consumer pins them, and all three are single-pipeline checks whose
verdict cannot change.
Left alone deliberately: 14 sites whose writer is a command, not a shell
builtin — they either absorb the writer's status with `|| true` or are python3
and awk, which write once at exit — and one file with no pipefail. `printf '%s'`
sites differ from a here-string only by a trailing newline, which no -q verdict
on a non-empty pattern depends on.
tests/test-no-pipefail-early-exit-grep.sh is a static guard against new
occurrences, discovered automatically by run-tests.sh. It only scans files that
set pipefail, joins continuation lines, skips comments, and flags only
echo/printf writers. Its first case proves the scanner can fail before its
second trusts a clean verdict on the tree.
A guard covers exactly the spellings its regex models, so the miss surface was
measured rather than assumed. Four were found and closed: pipefail declared as
`set -o errexit -o pipefail` (where the old pattern required pipefail to follow
the FIRST -o, and a file-level miss skips every site in that file); a writer
separated from grep by an intermediate stage; a pipeline wrapped on a trailing
`|` rather than a backslash; and readers spelled egrep, fgrep, /bin/grep,
`command grep` or with an env-var prefix. Segment characters exclude a bare `&`
so `echo ok && other | grep -q x`, whose writer is `other`, does not false-fire.
Widening surfaced 5 live sites invisible to the original scanner, all in
tests/test-apm-current-hook.sh, all `echo "$out" | json_field ... | grep -q`;
they are safe today only because json_field is python3, which reads to EOF and
writes once. Fixtures go 4 to 12 vulnerable spellings plus near-miss negatives.
Two `grep ... | head -1` sites (test-vale-wrap.sh) are the same race with a
different early-exiting reader, and are fixed by absorbing the writer. The
scanner deliberately does not model `head`, `sed -n 1p` or a bare `read`: most
legitimate uses in this tree are already absorbed with `|| true` and the scanner
cannot see absorption from pipeline text, so a high false-positive rate would be
how this guard gets weakened. Heredoc bodies are scanned as code; none in the
tree trips it today.
Impact
The bug predates the factory-audit merge: every converted site in
check-release-needed and case 21 dates to 4d018af and aa8cc22 (2026-08-09).
Test suites go 19 to 20. `run-tests.sh --strict` passes 20/20 with 0 skipped,
four consecutive runs.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01YR2CjVumUbEGWcMikcoXBD
