mosaic-coder 7714697f7a fix(wake): #927 enqueue TOCTOU — move stale-tmp cleanup off the hot enqueue path ...

cmd_enqueue called _wake_init_dir() (which reaped EVERY .wake.tmp.*
unconditionally) BEFORE taking the enqueue lock. So a 2nd enqueue's PRE-LOCK
cleanup deleted the LIVE in-flight tmp of a 1st enqueue that held the lock
through its atomic write -> spurious "durable pending write FAILED" abort of a
valid enqueue. Reachable under live co-feed (detector + reconciler concurrently
enqueue).

Fix (scalpel, Mos's lean = off the hot path):
- _wake_init_dir no longer reaps tmps; it only ensures the layout. Nothing on
  the enqueue/consume/cursors/ack hot paths can clobber a concurrent live write.
- _wake_clean_stale_tmp is AGE-SCOPED (-mmin +${WAKE_TMP_STALE_MIN:-5}) so it
  can only remove demonstrably-orphaned crash-left tmps, never a live (ms-old)
  in-flight write — safe even if it ever overlaps a concurrent enqueue.
- Reaping runs as an explicit MAINTENANCE action at store.sh init (daemon-start)
  and the detector poll tick, bounding accumulation once-per-pass, not raced
  per-enqueue.

#908 seq-integrity is unchanged (single store-side allocator, atomic
allocate+enqueue under flock, arrow-1 no-burn, anti-swallow fail-loud).
reconcile.sh is unchanged: an aborted enqueue advances neither the seen-ledger
nor observed_seq, so the source is re-enumerated next reconcile cycle (no
obligation loss).

Tests: new deterministic RED->GREEN harness test-wake-store-enqueue-race.sh
(PATH-shadowed mv/flock freeze enqueue A at its rename while B runs its pre-lock
cleanup — RED pre-fix: A aborts; GREEN post-fix: both succeed, distinct gapless
seqs {1,2}, zero spurious aborts). T5 updated to assert the hot path no longer
reaps tmps and that the maintenance path reaps a demonstrably-orphaned tmp. All
store-ack groups incl T10 stay green. manifest 0.6.4 -> 0.6.5.

Closes #927
Part of #892

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

2026-07-26 05:27:55 -05:00

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