Review round three on PR #235, plus the diagnosis of its first CI run:
all five test legs failed on one test, deterministically, while
sixteen local cores stayed green.
The mid-walk cancellation bound could not bite the per-entry poll
alone. The cancel lands two files into a 41-file directory --- root
contributes three dir entries --- so with the per-entry poll deleted
the directory finishes and the per-DIRECTORY poll catches at seen ==
44, under the old bound of 60. The bound is now 40 against an expected
exactly-35 (3 + one 32-entry poll stride), and the entry-poll-only
bite goes red at 44. Verified both ways.
The retirement helper observed a REQUEST, not settlement: it returned
as soon as an active row showed cancel_requested, which a worker that
ignored the token and completed successfully would satisfy. It now
waits for a completed row with status == "cancelled", making the
lane's "settles cancelled" claim true at the witness, not just at the
Rust layer.
The CI red: d3_pump(1600) between the mid-walk join and the late.bbb
write assumed the held walk would complete within 1.6 s. On a 3-thread
CI pool, 8 sleeps of 1200 ms drain in ~3.6 s of waves, so the file
landed before the held walk even STARTED and folded into the joiner's
baseline --- exactly the fold the test exists to assert for mid.bbb,
applied to the wrong file. Deterministic on every 2-4-core runner,
invisible on 16 cores. The drain is now an observable condition ---
at least one post-join walk completed and none active --- with the
saturation sleeps at 800 ms, and the three saturation tests plus the
whole eighteen-test family re-run green under taskset -c 0-3, the CI
pool shape reproduced locally.
A fixed-duration pump against pool-dependent timing is a core-count
assumption in disguise; the lane records it as such.
Superseded round-one text in the lane (the fallback "unreachability"
claim round two disproved) is corrected in place.
One gate run also hit the live attach-retry BrokenPipe row --- fourth
occurrence, all three required fragments verified against the durable
sweep log, recorded in docs/ci-red-signatures.md. This lane touches no
pmacs-gpu code, no wire, and no protocol; the same sweep passed twice
earlier the same day on materially the same tree. The retirement bar
(mechanism, not rate) is unchanged.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Levi Neuwirth
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