The #102827 corruption is pure zero holes -- frames lost across a WAL
generation. SessionDB.close() produces exactly that when it runs against a
file another live handle is still writing: PRAGMA wal_checkpoint(PASSIVE),
then the connection close that lets SQLite unlink -wal/-shm. The dangerous
event is a physical close overlapping any other live physical lifetime for
the same path, so both sides of it are closed here.
Late write vs. close: a cron watchdog timeout only stops waiting, and
ThreadPoolExecutor.shutdown(wait=False) cannot interrupt a worker already
inside run_conversation. The agent and its registry reference are now held
until that worker's Future completes, so its last frames land before any
checkpoint.
Close vs. open: the per-path barrier now COUNTS admitted teardowns. A path
can own several closes at once -- the current generation's final release and
a retired generation's drain are admitted independently under the registry
lock, and the per-path mutex only serializes teardowns that already entered
it. With one bare event per path, a releasing thread descheduled between
generation removal and the mutex let the next teardown to settle remove and
signal the shared event: close_all() returned over a pending close and
acquire() published a replacement writer on top of a handle still inside
checkpoint/unlink. _TeardownBarrier tracks event + pending count,
_admit_teardown_locked registers each close in the same lock section that
removes the generation, and only the last settled teardown lifts the
barrier. Physical I/O stays outside the registry lock and unrelated paths
still progress independently.
The auto-archive sweep called release_or_close in its finally while the
import was local to a different function, so every eligible sweep raised
NameError, the outer except Exception swallowed it at debug level, and the
borrowed registry reference was never returned -- a holder leak that pins a
retired generation open. The helper is now bound in the calling scope.
Remaining in-process writable SessionDB() call sites (trace upload, the
API-server profile cache, the web-server writable paths, startup schema
reconcile) go through the canonical registry acquire/release_or_close, and
gateway maintenance borrows pinned handles instead of iterating an unpinned
snapshot.
Regressions: overlapping final releases of the current and retired
generations in both orderings with the first paused before the lifecycle
mutex, teardown-error settlement, an unrelated-path control, and refcount
assertions for the auto-archive sweep on success, on failure, across
repeated sweeps and with auto-archive disabled.
Fixes#102827
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01BzxCWw6SuHXhXMdkiEwMa2
aad74f26f9