9.5 KiB
CI red signatures — the triage registry
This file is the single authority for judging a red CI run. It is an occurrence ledger, not a flake list: a row records what was seen, what is known about why, and what would retire it. A row is not a claim that the failure is harmless.
Deliberately not named "flakes". One of its rows is a possible product defect, and a filename that called it a flake would confer immunity the evidence does not support.
Read this before attributing any red run to the environment. Landed framing documents keep their own historical evidence and reasoning — that is not duplication, and it is not superseded by this file. What lives here is live triage policy.
How a row matches
A test-name match is never sufficient. A red run matches a row only when all three hold:
- the exact test selector matches;
- the job / flavor matches;
- every required fragment is present in the failure output.
Where a fragment lists alternatives (ESRCH / No such process), any
one satisfies that requirement — those are the same condition rendered
differently by platform or libc.
Fragments are normalized, never pasted verbatim. PIDs, elapsed times, thread ids and rendered OS-error suffixes vary between runs; a verbatim key would match nothing. The evidence link preserves the exact occurrence.
A failure in a listed test that does not carry that row's fragments is a NEW incident, judged on its own. The process test below is why this rule exists: it produced two signatures with different mechanisms and different causal status, and only one of them is a test bug.
The rerun rule
This replaces "rerun before concluding", which conflated three different outcomes.
- A green rerun after a red establishes INTERMITTENCE ONLY. It does not establish environmental cause, harmlessness, or retirement.
- The same signature on the rerun is a SECOND OCCURRENCE. It remains blocking pending investigation or a merge-base control.
- A different signature is a NEW INCIDENT, judged independently.
A merge-base control — running the same command on the merge base — is what distinguishes "this branch caused it" from "this tree has it". It is cheaper than argument and is the correct response to a second occurrence.
What retires a row
Retirement is causal, never a count of green runs. A row is retired by removing or explaining its mechanism:
| causal status | retirement condition |
|---|---|
| test race | hardening that removes the named mechanism, plus a discriminating witness for the stronger predicate |
| measurement design | the owning lane replaces or justifies the measurement and pins the resulting claim |
| unresolved | diagnosis and an explicit disposition |
| mechanism named, no occurrence | a linked occurrence promotes it to one of the above; sustained absence is not retirement, because nothing was ever measured |
Main-branch greens are occurrence evidence and accumulate toward a rate. They retire nothing by themselves. Retired rows stay in this file with their disposition, so a recurrence is recognisable.
Live rows
R1 — supersede cancellation budget
| field | value |
|---|---|
| selector | --lib async_runtime::tests::supersede_cancels_in_flight_job_within_50ms |
| job / flavor | macOS / luajit |
| required fragments | supersede did not cancel within 50ms |
| causal status | measurement design |
| evidence | #213 run 30826884642 |
| retirement | the async-runtime lane replaces or justifies the measurement (Q#MCI3) |
The test's premise is thread::sleep(15ms), asserted by comment to mean
"the worker picked the job up"; under load it may not have, in which case
the test measures the queued path while claiming the running one. And
its 50ms clock starts before the second dispatch and is consumed by the
test's own tick() + sleep(1ms) pump, so the interval is dominated by
when the test was scheduled. Widening the budget would make it pass
and measure nothing more.
R2 — USR1 delivered before the trap is installed
| field | value |
|---|---|
| selector | --lib process::tests::a_successful_signal_disposition_depends_on_whether_it_is_fatal |
| job / flavor | macOS / lua54 |
| required fragments | leader=exited( + SIGUSR1 |
| causal status | test race |
| evidence | #213 run 30927084982 attempt 1 |
| retirement | the fixture proves the trap is installed, with a witness that fails without it |
Readiness is ProcessEventKind::Started, emitted at spawn — not when
/bin/sh has parsed trap '' USR1. SIGUSR1's default disposition is
terminate, so a signal inside that window kills the child. The fixture's
own comment states the requirement it does not enforce.
R3 — live-leader EPERM with an unobservable group
| field | value |
|---|---|
| selector | --lib process::tests::a_successful_signal_disposition_depends_on_whether_it_is_fatal |
| job / flavor | macOS / lua54 |
| required fragments | EPERM and measured_group=unobservable( and (ESRCH / No such process) and leader=live |
| causal status | UNRESOLVED — possible product defect |
| evidence | #214 run 30932558752 attempt 1 |
| retirement | diagnosis and disposition by the process-signal / reap-ledger lanes. Never a green rerun. |
Same test as R2, different mechanism, different status. This is the
group-target behaviour #176 and #200 circled and the reap-ledger lane
parked every disposition change pending: a group-directed kill returned
EPERM while the leader was observed live, and measured_group — the one
field able to disagree — could not be read at all.
Do not treat a red matching this row as environmental. A green rerun changes nothing about it.
R4 — readiness predicate satisfied by an empty file
| field | value |
|---|---|
| selector | --test vterm_stage2_acceptance terminal_escape_gates_local_bindings_and_double_escape_sends_interrupt |
| job / flavor | macOS / luajit |
| required fragments | left: [] and right: [49] |
| causal status | test race |
| evidence | #214 run 30932558752 attempt 1 |
| retirement | wait_for_file requires the expected content, with a witness that fails against a zero-byte file |
wait_for_file returns as soon as fs::read succeeds — which succeeds
on a zero-byte file. The probe writes readiness with
open(path,'wb').write(b'1'), and open() creates the file before
write() fills it. The predicate is "readable"; the assertion is
"contains 1" (49 is ASCII '1').
Audited incumbents — mechanism named, no occurrence recorded
These were carried in the handoff's hazards list without evidence. The audit found the tests real and the mechanisms plausible, so they are neither confirmed nor deleted: they are recorded honestly as unmeasured.
Nothing here confers "known flaky". A red matching one of these is a first recorded occurrence and should be investigated, not reruns-to-green.
R5 — GPU terminal cell background did not paint
| field | value |
|---|---|
| selector | -p pmacs-gpu a33_headless_terminal_frame_paints_cells_without_document_layers |
| job / flavor | GPU Render (headless), under parallel load |
| required fragments | the terminal cell background did not paint + blue pixels |
| causal status | mechanism named, no occurrence recorded |
| evidence | none linked. The assertion string is real (pmacs-gpu/src/main.rs:17973); no run was ever cited |
| retirement | a linked occurrence promotes this row; absence retires nothing, because nothing was measured |
R6 — supervisor reap across cycles
| field | value |
|---|---|
| selector | --test m6_8_multi_repl_acceptance m6_8_supervisor_reaps_all_children_across_cycles |
| job / flavor | not recorded |
| required fragments | not recorded — no signature was ever captured |
| causal status | mechanism named, no occurrence recorded ("timing-based", 10 cycles) |
| evidence | none linked |
| retirement | a linked occurrence with a signature promotes this row |
R6 cannot currently be matched. Without required fragments there is no rule to apply, so a red in this test is a new incident by default. That is the correct outcome for an entry that never carried evidence.
Occurrence log
| date | run | row | outcome |
|---|---|---|---|
| 2026-08-04 | 30826884642 | R1 | rerun green — intermittence only |
| 2026-08-04 | 30927084982 att.1 | R2 | rerun green — intermittence only |
| 2026-08-04 | 30932558752 att.1 | R3, R4 | rerun green — intermittence only; R3 remains unresolved |
Four incidents, three tests, four signatures. Count signatures: the process test contributed two, and only one of them is a test bug.
The #214 occurrence is the strongest available evidence that these are
not caused by the PRs they appeared on — that PR is docs-only and its
tree is byte-identical to a green main. It is not evidence that any
of them is harmless.