[BUG]: Delete session leaves data in database and on disk — race condition erases Deleted event before projector fires #30814

Description

Clicking "delete session" in the UI does not always remove the session data from the database. The session row, messages, and related records can persist because of a race condition in the deletion pipeline.

Race condition: Deleted event is erased before projector processes it

File: packages/opencode/src/session/session.ts:664-665

yield* events.publish(SessionV1.Event.Deleted, { sessionID, info: session })
yield* events.remove(sessionID)

Line 664 publishes a SessionV1.Event.Deleted event to the event store. Line 665 immediately calls events.remove(sessionID) which deletes ALL events for this session from both EventTable and EventSequenceTable (packages/core/src/event.ts:445-454).

The projector at packages/core/src/session/projector.ts:248-250 listens for Deleted events asynchronously:

yield* events.project(SessionV1.Event.Deleted, (event) =>
  db.delete(SessionTable).where(eq(SessionTable.id, event.data.sessionID)).run().pipe(Effect.orDie),
)

If the projector has not processed the Deleted event before events.remove() deletes the event stream, the projector never fires. The session row and all cascade-related data remain in the database. No error is shown because the catch block at lines 666-668 silently swallows all exceptions.

Additionally, events.remove() is redundant — ON DELETE CASCADE from SessionTable (defined in packages/core/src/session/sql.ts) would clean up event rows automatically when the session row is deleted.

Note: Bugs 2-6 (tool output files, truncated output files, plan files, legacy storage, in-memory caches not cleaned up) overlap with existing issues #29694 and #16101. This issue focuses on the race condition only.

Suggested Fix

Remove the events.remove(sessionID) call at session.ts:665. The cascade delete from SessionTable already handles event cleanup. If the events.remove() is needed for a specific purpose, move it to the projector handler so it runs after the Deleted event is processed.

OpenCode version

main

Steps to reproduce

1. Create a new session and exchange several messages
2. Delete the session from the UI
3. Query the SQLite database: SELECT COUNT(*) FROM session WHERE id = '<session-id>'
4. The session row may still exist because the projector never received the Deleted event

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Operating System

All

Terminal