The active-session external-refresh check (refreshActiveSessionIfExternallyUpdated)
force-reloaded the whole transcript whenever last_message_at/updated_at advanced.
The post-turn background skill/memory review bumps those timestamps without adding
any chat messages, so the destructive loadSession(force) (clears S.messages, awaits
a round-trip) made the open conversation visibly disappear and reappear with no new
content.
The refresh now reloads only when the message count actually changed, and treats a
timestamp-only bump as metadata (advance the local last-seen marker + refresh the
lightweight sidebar list, no transcript teardown).
Maintainer fix on top of the contributor's PR (Codex gate): the count check fires
in BOTH directions — remoteCount !== localCount, not just >. A LOWER remote count
means another tab/client truncated/undid/retried/regenerated the transcript
(/api/session/truncate, /retry, /undo all shrink s.messages and persist a lower
message_count); the original >-only gate would have treated that as metadata-only
and silently kept the stale longer transcript forever. Added a regression test for
the count-decrease case. The pending-user-message count-inflation path is excluded
by the existing busy/active-stream guards.
Co-authored-by: allenliang2022 <allenliang2022@users.noreply.github.com>
4f64443f63
