Some system apps show 'waiting to back up...', no log, only status: -2001

[grote]

Chromium, Calculator, Messaging, Work profile never get backup status recorded, because the system doesn't call the normal API callbacks. We only see this in the log:

2024-09-27 10:32:57.145 27291-27379 Notificati...upObserver com.stevesoltys.seedvault            I  Completed. Target: org.chromium.chrome, status: -2001
2024-09-27 10:32:57.145 27291-27379 Notificati...upObserver com.stevesoltys.seedvault            I  Showing progress notification for org.calyxos.bellis 504/695
2024-09-27 10:32:57.149 27291-27379 Notificati...upObserver com.stevesoltys.seedvault            I  504/695 - Chromium (org.chromium.chrome)
2024-09-27 10:32:57.151 27291-27379 Notificati...upObserver com.stevesoltys.seedvault            I  Completed. Target: org.fdroid.fdroid.privileged, status: -2001
2024-09-27 10:32:57.151 27291-27379 Notificati...upObserver com.stevesoltys.seedvault            I  Showing progress notification for org.chromium.chrome 505/695

Best start for debugging this is recompiling AOSP with more verbose DEBUG logging enabled and see if anything gets logged there to give a clue.

[grote]

    /**
     * Indicates that backup is either not enabled at all or
     * backup for the package was rejected by backup service
     * or backup transport,
     *
     * @hide
     */
    @SystemApi
    public static final int ERROR_BACKUP_NOT_ALLOWED = -2001;

May be related to D2D of system apps. Strange, that I saw this as an intermittent error for bromite as well in CI integration tests.

[grote]

Ok so the problem is that affected system apps have set allowBackup="false" and even when using D2D, the system honors that (for system apps only).

[grote]

#750 now exposes the real reason, not showing "waiting for backup".