[Bug]: Deck 1.18.2 + notify_push 1.3.3 on NC34 — opening any board returns 404 (dirty table reads in LiveUpdateListener)

[ssergio-ll]

Describe the bug

After upgrading to Nextcloud 34.0.1, opening any board in Deck returns Request failed with status code 404. The issue only occurs when notify_push is enabled. Disabling notify_push (occ app:disable notify_push) resolves the problem immediately.

To Reproduce

1. Have Nextcloud 34.0.1 running with Deck 1.18.2 and notify_push 1.3.3 enabled
2. Open Deck from the top navigation menu
3. Click on any board
4. Frontend immediately returns: Request failed with status code 404

Expected behavior

The board loads normally.

Server details

Operating system: Synology DSM (ARM64)
PHP version: 8.4
Nextcloud version: 34.0.1
Deck version: 1.18.2
notify_push version: 1.3.3

What happens

The request PUT /ocs/v2.php/apps/deck/api/v1.0/session/create fails. The following exception appears in nextcloud.log at level 0 (debug):

Exception: dirty table reads: SELECT `id`, `board_id`, `last_contact`, `user_id`, `token`
FROM `oc_deck_sessions` 
WHERE (`board_id` = :dcValue1) AND (`last_contact` > :dcValue2)

Stack trace

SessionController::create()
  → SessionService::initSession()
  → EventDispatcher::dispatchTyped(SessionCreatedEvent)
  → LiveUpdateListener::handle()              [LiveUpdateListener.php line 73]
  → SessionService::notifyAllSessions()
  → SessionMapper::findAllActive()            [SessionMapper.php line 49-51]
    → QueryBuilder::executeQuery()
      → Exception: dirty table reads          [Connection.php line 407]

Root cause analysis

NC34 appears to have tightened enforcement of "dirty table reads" detection (reads outside an active DB transaction). When a user opens a board, LiveUpdateListener fires a SessionCreatedEvent and attempts to notify active sessions via notify_push/Redis. Inside that event handler, SessionMapper::findAllActive() executes a SELECT on oc_deck_sessions outside a transaction. In NC34 this triggers an exception that aborts the entire request, which the frontend receives as a 404.

Workaround

Disabling notify_push resolves the issue:

occ app:disable notify_push

Workaround that does NOT work

occ config:app:set deck disable_push_notifications --value=1

This config key has no effect — the LiveUpdateListener still fires and the exception still occurs.

Suggested fix

The SELECT in SessionMapper::findAllActive() called from LiveUpdateListener should be wrapped in a proper transaction context, or the dirty read check should be explicitly bypassed for this read-only lookup in the event listener.

This issue started after upgrading from Nextcloud 33 to Nextcloud 34.0.1.