Files
msd-core/tests
Tom Boucher c043f2946c fix(#2914): per-PR ack fragments instead of one shared mutable file (#2923)
* fix(#2914): never persist a spent emitted-drift ack on next

tests/emitted-drift-ack.json held 34 spent #2834 entries merged via #2900.
Every entry is scoped to the diff that introduced it (#2789), so once merged
to next it is at the base by definition -- spent and inert. Its presence is
still load-bearing though: each PR rewrites the paths map wholesale, making a
persistent base copy a shared cell. Five of six conflicting PRs in the open
queue collided on this file and nothing else.

Deletes the stale document and adds a push-to-next guard asserting it stays
absent. The guard is deliberately NOT wired into lint:ci -- a PR-lane check
against the base is the #2768 shape #2789 exists to end.

Closes #2914

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

* chore(#2914): backfill changeset pr number

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

* fix(#2914): per-PR ack fragments instead of one shared mutable file

The emitted-drift acknowledgment lived in a single tests/emitted-drift-ack.json
whose paths map every PR rewrote wholesale. That is a shared mutable cell: any
two PRs needing an ack edit the same lines and conflict. Five of six conflicting
PRs in the open queue collided on this file and nothing else.

Acks now live as per-PR fragments under tests/emitted-drift-acks/, the same
shape .changeset/ already uses to solve this exact problem. Two PRs pick
different filenames, so they cannot collide, and fragments lingering on next
are harmless rather than toxic.

The legacy file's 35 entries are MIGRATED into a fragment, not deleted. An
earlier delete-only attempt failed verification twice: the ratchet lost the
spec-phase.md acknowledgment from #2779 and reported a 10-byte growth with no
ack. Relocating preserves every acknowledgment.

The legacy single file is still READ (unioned with the fragments) because five
open PRs carry it; dropping support would break all of them. A duplicate path
key across sources is a hard error, never last-wins.

The push-to-next guard is retargeted accordingly: it now asserts only that the
legacy SHARED file never reappears on next. Fragments may persist harmlessly.

Closes #2914

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 5 <noreply@anthropic.com>
2026-07-31 13:15:29 -04:00
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