Files
msd-core/tests
sim 573d39ea60 fix(#3103): refuse to reap on a PID the parse could not represent
A lock file whose PID is a digit string longer than 308 characters parses to
Infinity, not NaN. The default liveness helper then calls process.kill with it,
which throws a TypeError rather than an errno error, and that helper's catch
only recognises EPERM — so it returns false, meaning "the owner is dead", and
the worktree becomes eligible to be removed.

The reaper already fails closed for this exact situation. It wraps the liveness
call in a catch that sets alive and does not reap, with a comment saying
liveness could not be determined. That protection never fires here, because the
inner catch swallowed the error first and answered confidently instead of
admitting it did not know. A guard that cannot verify safety reporting success
is the defect this whole epic is named for, and it was sitting inside the one
function in the tree that deletes things.

The guard deleted earlier on this branch tested for NaN. That test really was
dead — a digits-only capture cannot parseInt to NaN — but the reachable failure
is non-finite, so removing it without correcting the predicate left the hole
open. The check is now for a finite value, and a malformed PID reports the same
lock_owner_unknown skip as an unparseable one, since both mean the same thing:
the owner is unknown, so nothing is removed.

Measured, not assumed: 308 nines still parse finite, 309 are Infinity. All
three of that boundary are covered, along with a 400-digit case that asserts
the worktree is still on disk afterwards — the consequence, not just the
verdict. Against a build with the guard removed, that case reports
pid_dead_and_merged and the worktree is gone.

The liveness helper's own catch still maps every non-EPERM error to "dead". The
fix belongs where the value stops being trustworthy rather than at the far end
of it, but that helper is worth revisiting on its own terms.

Refs #3057

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
2026-08-06 01:08:15 -04:00
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