I couldn't figure out how to label this issue, so I've labeled it for a human to triage. Hang tight.

@nidegen Thanks for the report. The issue is likely related to the Firestore AppCheck integration that was introduced in 8.9.0

That's what I was also thinking, but was unable to trace the exact origin. The often called AppCheck Notification Observer of tokenDidChangeNotificationName did always have if (![[contents->app name] isEqual:notified_app_name]) { return } return in FirebaseAppCheckCredentialsProvider.

(Line 52 of firebase_app_check_credentials_provider_apple.mm)

@nidegen Do you install App Check SDK as well?

I guess the issue may be due to app_check == nil here so nil is passed as a notification name to the method which means the class subscribes to basically all possible notifications.

cc @schmidt-sebastian

Nope, I do not use it or link to it!

The underlying issue seems to be that the AppCheck callback is processing a notification whose userInfo is not an NSDictionary. While this does not conform to the NSNotification API, this can easily happen in Objective C. 8.9.1 will start to ignore these notifications.

@nidegen Firebase 8.9.1 is now available. We would appreciate your confirmation that it fixes the issue.