FirebaseApp.UserUnlockReceiver.unregister crashes

[consp1racy]

• Firebase Component: Common
• Component version: 20.4.2

Steps to reproduce:

Crashlytics notified us about a crash in FirebaseApp.UserUnlockReceiver.unregister. The method is only called from FirebaseApp.UserUnlockReceiver.onReceive which in turn only responds to android.intent.action.USER_UNLOCKED. I don't know how many times the system sends the broadcast but it apparently isn't just once.

Relevant Code:

firebase-android-sdk/firebase-common/src/main/java/com/google/firebase/FirebaseApp.java

Lines 668 to 680 in b77c218

	public void onReceive(Context context, Intent intent) {
	// API initialization is idempotent.
	synchronized (LOCK) {
	for (FirebaseApp app : INSTANCES.values()) {
	app.initializeAllApis();
	}
	}
	unregister();
	}
	public void unregister() {
	applicationContext.unregisterReceiver(this);
	}

FirebaseApp initialization may be idempotent but Context.unregisterReceiver isn't. The method crashes if the receiver isn't registered.

Suggested solution

public void unregister() {
  try {
    applicationContext.unregisterReceiver(this);
  } catch (IllegalArgumentException ignore) {
    // The receiver isn't registered.
  }
}

[google-oss-bot]

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

[consp1racy]

Workaround

val context = object : ContextWrapper(this) {
    override fun getApplicationContext(): ContextWrapper {
        return this
    }

    override fun unregisterReceiver(receiver: BroadcastReceiver?) {
        try {
            super.unregisterReceiver(receiver)
        } catch (_:IllegalArgumentException) {
        }
    }
}
FirebaseApp.initializeApp(context)

EDIT: Maybe it won't be that easy. I got this log

E/FirebaseSessions: Failed to register lifecycle callbacks, unexpected context class ...

[lehcar09]

Hi @consp1racy, thank you for reaching out. We appreciate you investigating the issue and providing the fix. I'll inform our engineers about this with your pull request.

[rlazo]

Hi @consp1racy thanks for reaching out, and providing a fix! I'll review the code and run the tests required to include it in the codebase.