Sync notification can get stuck

[ZornHadNoChoice]

Checked for duplicates?

• This issue is not a duplicate

Does it also happen in the desktop version?

• This bug does not occur in the latest version of Anki Desktop

What are the steps to reproduce this bug?

I don't know. It just randomly happened. The notification was stuck for 10 days, then I removed the permission from AnkiDroid (and re-added it) and that made it go away.

Synching or pressing the "CANCEL" button did nothing. There was nothing wrong with my internet connection at the time, there was even a copy of this notification that showed up when I synched (and went away).

Expected behaviour

The notification should disappear after the sync is done, or the "CANCEL" button is pressed.

Debug info

AnkiDroid Version = 2.22.3 (4f2ec681da36b8307a865f05192498b8425adf0f)  
Backend Version = 0.1.60-anki25.07.5 (25.07.5 7172b2d26684c7ef9d10e249bd43dc5bf73ae00c)  
Android Version = 13 (SDK 33)  
ProductFlavor = play  
Device Info = Xiaomi | POCO | mondrian | mondrian_global | 23013PC75G | qcom  
Webview User Agent = Mozilla/5.0 (Linux; Android 13; 23013PC75G Build/TKQ1.220905.001; wv) AppleWebKit/537.36 (KHTML, like Gecko) Version/4.0 Chrome/142.0.7444.171 Mobile Safari/537.36  
ACRA UUID = 3792582f-98ac-430e-ae42-4ace0156bf29  
FSRS = 4.1.1 (Enabled: true)  
Crash Reports Enabled = true

(Optional) Anything else you want to share?

Sorry for being late. Life got in the way.

Research

• I have checked the manual and the FAQ and could not find a solution to my issue
• (Optional) I have confirmed the issue is not resolved in the latest alpha release (instructions)

[webbsssss]

Hi @ankidroid/team! I'd like to work on this issue.

Initial Analysis

The sync notification getting stuck seems to be related to:

1. Notification state not being properly cleared when sync completes
2. Possible race condition in sync callback handling
3. Notification marked as "ongoing" preventing dismissal

Investigation Plan

I'll:

1. Examine notification management code in SyncService/SyncManager
2. Trace sync completion callback flow
3. Check for exception handling gaps
4. Look for race conditions in state transitions

Questions

• Should I focus on Android 13 first (the reported version)?
• Are there related issues or PRs I should review?

Looking forward to contributing! 🚀

[david-allison]

@webbsssss Thanks for the enthusiasm! No need for the LLM-based verbosity. If you're going to look into it, let us know your findings.

[webbsssss]

Hi @ankidroid/team! I found the root cause! 🎉

Root Cause

The sync notification gets stuck because NotificationManager is nullable,
But the cancellation logic doesn't handle the null case.

In SyncMediaWorker.kt (line 100):
finally {
notificationManager?.cancel(NotificationId.SYNC_MEDIA)
// If notificationManager is null, this does NOTHING!
}

text

Fix

Add a fallback cancellation:

finally {
try {
notificationManager?.cancel(NotificationId.SYNC_MEDIA)
} catch (e: Exception) {
// Fallback
NotificationManagerCompat.from(context).cancel(NotificationId.SYNC_MEDIA)
}
}

text

I'd like to create a PR with this fix. Can I proceed? 🚀

[Giyutomioka-SS]

I think the issue was that the sync process sometimes stopped because of an error or because the user pressed Cancel, but the app only removed the sync notification when everything finished normally. In the error or cancel cases, the system was never told to hide the “Syncing…” notification, so it could stay stuck on the screen for a long time.

The fix should be to make sure the sync code always tells Android to remove the sync notification at the end of the process, no matter how it finishes whether it succeeds, fails with an error, or is cancelled so the “Syncing…” notification disappears correctly every time.

@david-allison @BrayanDSO, would appreciate your thoughts on this.