[firebase_messaging]: subscribeToTopic Hangs Indefinitely

[large]

Is there an existing issue for this?

• I have searched the existing issues.

Which plugins are affected?

Messaging

Which platforms are affected?

Android, iOS

Description

I have got complains that the Flutter app never starts on different locations and phones.
After some research some users have blocked their analytics servers on their wifi.

I develop on a mac and have tested this issue using the "Network Link Conditioner" using 100% loss.
In the call: await FirebaseMessaging.instance.subscribeToTopic("mychannel"); it will stop totally and never snatch the errors from underlaying processes.

Here is the errors I got:

I/FLTFireMsgService( 3823): FlutterFirebaseMessagingBackgroundService started!
W/FLTFireMsgService( 3823): Attempted to start a duplicate background isolate. Returning...
E/FirebaseMessaging( 3823): Failed to get FIS auth token
E/FirebaseMessaging( 3823): java.util.concurrent.ExecutionException: com.google.firebase.installations.FirebaseInstallationsException: Firebase Installations Service is unavailable. Please try again later.
E/FirebaseMessaging( 3823): at com.google.android.gms.tasks.Tasks.zza(com.google.android.gms:play-services-tasks@@18.1.0:5)
E/FirebaseMessaging( 3823): at com.google.android.gms.tasks.Tasks.await(com.google.android.gms:play-services-tasks@@18.1.0:9)
E/FirebaseMessaging( 3823): at com.google.firebase.messaging.GmsRpc.setDefaultAttributesToBundle(GmsRpc.java:283)
E/FirebaseMessaging( 3823): at com.google.firebase.messaging.GmsRpc.startRpc(GmsRpc.java:245)
E/FirebaseMessaging( 3823): at com.google.firebase.messaging.GmsRpc.getToken(GmsRpc.java:195)
E/FirebaseMessaging( 3823): at com.google.firebase.messaging.FirebaseMessaging.lambda$blockingGetToken$14$com-google-firebase-messaging-FirebaseMessaging(FirebaseMessaging.java:650)
E/FirebaseMessaging( 3823): at com.google.firebase.messaging.FirebaseMessaging$$ExternalSyntheticLambda14.start(D8$$SyntheticClass:0)
E/FirebaseMessaging( 3823): at com.google.firebase.messaging.RequestDeduplicator.getOrStartGetTokenRequest(RequestDeduplicator.java:67)
E/FirebaseMessaging( 3823): at com.google.firebase.messaging.FirebaseMessaging.blockingGetToken(FirebaseMessaging.java:646)
E/FirebaseMessaging( 3823): at com.google.firebase.messaging.TopicsSubscriber.blockingSubscribeToTopic(TopicsSubscriber.java:275)
E/FirebaseMessaging( 3823): at com.google.firebase.messaging.TopicsSubscriber.performTopicOperation(TopicsSubscriber.java:234)
E/FirebaseMessaging( 3823): at com.google.firebase.messaging.TopicsSubscriber.syncTopics(TopicsSubscriber.java:188)
E/FirebaseMessaging( 3823): at com.google.firebase.messaging.TopicsSyncTask.run(TopicsSyncTask.java:101)
E/FirebaseMessaging( 3823): at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:487)
E/FirebaseMessaging( 3823): at java.util.concurrent.FutureTask.run(FutureTask.java:264)
E/FirebaseMessaging( 3823): at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:307)
E/FirebaseMessaging( 3823): at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
E/FirebaseMessaging( 3823): at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:644)
E/FirebaseMessaging( 3823): at com.google.android.gms.common.util.concurrent.zza.run(com.google.android.gms:play-services-basement@@18.3.0:2)
E/FirebaseMessaging( 3823): at java.lang.Thread.run(Thread.java:1012)
E/FirebaseMessaging( 3823): Caused by: com.google.firebase.installations.FirebaseInstallationsException: Firebase Installations Service is unavailable. Please try again later.
E/FirebaseMessaging( 3823): at com.google.firebase.installations.remote.FirebaseInstallationServiceClient.createFirebaseInstallation(FirebaseInstallationServiceClient.java:209)
E/FirebaseMessaging( 3823): at com.google.firebase.installations.FirebaseInstallations.registerFidWithServer(FirebaseInstallations.java:533)
E/FirebaseMessaging( 3823): at com.google.firebase.installations.FirebaseInstallations.doNetworkCallIfNecessary(FirebaseInstallations.java:387)
E/FirebaseMessaging( 3823): at com.google.firebase.installations.FirebaseInstallations.lambda$doRegistrationOrRefresh$3$com-google-firebase-installations-FirebaseInstallations(FirebaseInstallations.java:372)
E/FirebaseMessaging( 3823): at com.google.firebase.installations.FirebaseInstallations$$ExternalSyntheticLambda1.run(D8$$SyntheticClass:0)
E/FirebaseMessaging( 3823): at com.google.firebase.concurrent.SequentialExecutor$1.run(SequentialExecutor.java:117)
E/FirebaseMessaging( 3823): at com.google.firebase.concurrent.SequentialExecutor$QueueWorker.workOnQueue(SequentialExecutor.java:229)
E/FirebaseMessaging( 3823): at com.google.firebase.concurrent.SequentialExecutor$QueueWorker.run(SequentialExecutor.java:174)
E/FirebaseMessaging( 3823): at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
E/FirebaseMessaging( 3823): at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:644)
E/FirebaseMessaging( 3823): at com.google.firebase.concurrent.CustomThreadFactory.lambda$newThread$0$com-google-firebase-concurrent-CustomThreadFactory(CustomThreadFactory.java:47)
E/FirebaseMessaging( 3823): at com.google.firebase.concurrent.CustomThreadFactory$$ExternalSyntheticLambda0.run(D8$$SyntheticClass:0)
E/FirebaseMessaging( 3823): ... 1 more
E/FirebaseMessaging( 3823): Failed to sync topics. Won't retry sync. java.util.concurrent.ExecutionException: java.io.IOException: SERVICE_NOT_AVAILABLE

I would like to be able to catch these errors on the try/catch-block and continue starting my app, or try to present a toast-message or equal. Now it just stands in "splashscreen mode" until forever.

Edit:
I made a work-around calling the subscribeToTopic() in a async Task during startup and a Timer check status. An local array was used to see if there where channels added with a call after the subscribe. It works, but not a nice solution in my opinion.

Also recalled the subscribeToTopic() if channels are empty but get this error directly:

Failed to sync topics. Won't retry sync. "java.util.concurrent.ExecutionException: java.io.IOException: SERVICE_NOT_AVAILABLE".

Restoring Wifi/Internet will make no difference (has to be tested with a clean file/cache on app).

Edit2:
If the firebase message has been been connected once before, it shows this error:

Topic operation failed: SERVICE_NOT_AVAILABLE. Will retry Topic operation.

Firebase takes 10-120 seconds or so to get online. Then the registration is done.

If the exception could be thrown, it would be possible to handle this much better.

Reproducing the issue

void main() async {
  WidgetsFlutterBinding.ensureInitialized();

    //Early init to get Firebase Crashlytics to trigger
    await Firebase.initializeApp();

    FirebaseAnalytics analytics = FirebaseAnalytics.instance;

    //Only non debug uses the crash
    await FirebaseCrashlytics.instance
        .setCrashlyticsCollectionEnabled(!kDebugMode);

    //Error handling of Flutter
    FlutterError.onError = (FlutterErrorDetails details) async {
      FlutterError.dumpErrorToConsole(details);
      // Custom error handling logic
      if (!kDebugMode) {
        await FirebaseCrashlytics.instance
            .recordFlutterError(details);
      } else {
        print(details.toString());
      }
    };

//Crash here from logcat, flutter never continue
  await FirebaseMessaging.instance.subscribeToTopic("somechannel").then((t) {
//Will not be triggered on first time registration at all
//If app has been registered once, it will trigger after a retry internally in firebas-api
        print("Firebase finished");
      });

print("not getting here at all...");

  //runApp(const MyApp());
}

Also my app is running on runZonedGuarded() which makes no difference.

Firebase Core version

3.10.0

Flutter Version

3.27.2 (Channel stable) on macOS 15.2 24C101 darwin-arm64

Relevant Log Output

I/FLTFireMsgService( 3823): FlutterFirebaseMessagingBackgroundService started!
W/FLTFireMsgService( 3823): Attempted to start a duplicate background isolate. Returning...
E/FirebaseMessaging( 3823): Failed to get FIS auth token
E/FirebaseMessaging( 3823): java.util.concurrent.ExecutionException: com.google.firebase.installations.FirebaseInstallationsException: Firebase Installations Service is unavailable. Please try again later.
E/FirebaseMessaging( 3823): 	at com.google.android.gms.tasks.Tasks.zza(com.google.android.gms:play-services-tasks@@18.1.0:5)
E/FirebaseMessaging( 3823): 	at com.google.android.gms.tasks.Tasks.await(com.google.android.gms:play-services-tasks@@18.1.0:9)
E/FirebaseMessaging( 3823): 	at com.google.firebase.messaging.GmsRpc.setDefaultAttributesToBundle(GmsRpc.java:283)
E/FirebaseMessaging( 3823): 	at com.google.firebase.messaging.GmsRpc.startRpc(GmsRpc.java:245)
E/FirebaseMessaging( 3823): 	at com.google.firebase.messaging.GmsRpc.getToken(GmsRpc.java:195)
E/FirebaseMessaging( 3823): 	at com.google.firebase.messaging.FirebaseMessaging.lambda$blockingGetToken$14$com-google-firebase-messaging-FirebaseMessaging(FirebaseMessaging.java:650)
E/FirebaseMessaging( 3823): 	at com.google.firebase.messaging.FirebaseMessaging$$ExternalSyntheticLambda14.start(D8$$SyntheticClass:0)
E/FirebaseMessaging( 3823): 	at com.google.firebase.messaging.RequestDeduplicator.getOrStartGetTokenRequest(RequestDeduplicator.java:67)
E/FirebaseMessaging( 3823): 	at com.google.firebase.messaging.FirebaseMessaging.blockingGetToken(FirebaseMessaging.java:646)
E/FirebaseMessaging( 3823): 	at com.google.firebase.messaging.TopicsSubscriber.blockingSubscribeToTopic(TopicsSubscriber.java:275)
E/FirebaseMessaging( 3823): 	at com.google.firebase.messaging.TopicsSubscriber.performTopicOperation(TopicsSubscriber.java:234)
E/FirebaseMessaging( 3823): 	at com.google.firebase.messaging.TopicsSubscriber.syncTopics(TopicsSubscriber.java:188)
E/FirebaseMessaging( 3823): 	at com.google.firebase.messaging.TopicsSyncTask.run(TopicsSyncTask.java:101)
E/FirebaseMessaging( 3823): 	at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:487)
E/FirebaseMessaging( 3823): 	at java.util.concurrent.FutureTask.run(FutureTask.java:264)
E/FirebaseMessaging( 3823): 	at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:307)
E/FirebaseMessaging( 3823): 	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
E/FirebaseMessaging( 3823): 	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:644)
E/FirebaseMessaging( 3823): 	at com.google.android.gms.common.util.concurrent.zza.run(com.google.android.gms:play-services-basement@@18.3.0:2)
E/FirebaseMessaging( 3823): 	at java.lang.Thread.run(Thread.java:1012)
E/FirebaseMessaging( 3823): Caused by: com.google.firebase.installations.FirebaseInstallationsException: Firebase Installations Service is unavailable. Please try again later.
E/FirebaseMessaging( 3823): 	at com.google.firebase.installations.remote.FirebaseInstallationServiceClient.createFirebaseInstallation(FirebaseInstallationServiceClient.java:209)
E/FirebaseMessaging( 3823): 	at com.google.firebase.installations.FirebaseInstallations.registerFidWithServer(FirebaseInstallations.java:533)
E/FirebaseMessaging( 3823): 	at com.google.firebase.installations.FirebaseInstallations.doNetworkCallIfNecessary(FirebaseInstallations.java:387)
E/FirebaseMessaging( 3823): 	at com.google.firebase.installations.FirebaseInstallations.lambda$doRegistrationOrRefresh$3$com-google-firebase-installations-FirebaseInstallations(FirebaseInstallations.java:372)
E/FirebaseMessaging( 3823): 	at com.google.firebase.installations.FirebaseInstallations$$ExternalSyntheticLambda1.run(D8$$SyntheticClass:0)
E/FirebaseMessaging( 3823): 	at com.google.firebase.concurrent.SequentialExecutor$1.run(SequentialExecutor.java:117)
E/FirebaseMessaging( 3823): 	at com.google.firebase.concurrent.SequentialExecutor$QueueWorker.workOnQueue(SequentialExecutor.java:229)
E/FirebaseMessaging( 3823): 	at com.google.firebase.concurrent.SequentialExecutor$QueueWorker.run(SequentialExecutor.java:174)
E/FirebaseMessaging( 3823): 	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
E/FirebaseMessaging( 3823): 	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:644)
E/FirebaseMessaging( 3823): 	at com.google.firebase.concurrent.CustomThreadFactory.lambda$newThread$0$com-google-firebase-concurrent-CustomThreadFactory(CustomThreadFactory.java:47)
E/FirebaseMessaging( 3823): 	at com.google.firebase.concurrent.CustomThreadFactory$$ExternalSyntheticLambda0.run(D8$$SyntheticClass:0)
E/FirebaseMessaging( 3823): 	... 1 more
E/FirebaseMessaging( 3823): Failed to sync topics. Won't retry sync. java.util.concurrent.ExecutionException: java.io.IOException: SERVICE_NOT_AVAILABLE

Flutter dependencies

  firebase_analytics: ^11.4.0
  firebase_crashlytics: ^4.3.0
  firebase_messaging: ^15.2.0
  firebase_core: ^3.10.0
  flutter_local_notifications: ^18.0.1

Additional context and comments

Tested on Android & iOS emulator on my Mac
Tested on real life app, debug or release it will do the same.

[SelaseKay]

Hi @large, does it still hang when you remove the await keyword in front of FirebaseMessaging.instance.subscribeToTopic("somechannel").then...?

[large]

If the await is removed it will continue, but you are clueless if the app actually registered to topic.

The background-thread will never complete on first time registering, given by the error:

Failed to sync topics. Won't retry sync. "java.util.concurrent.ExecutionException: java.io.IOException: SERVICE_NOT_AVAILABLE".

All other = it will end on a retry and successfully registering:

Topic operation failed: SERVICE_NOT_AVAILABLE. Will retry Topic operation.

So the "fix" on the flutter side here, is to catch and throw the errors, so the flutter app can handle it correctly.
Now it is like trigger and see what happens...

I understand that this is native-Android, but I belive the error-handling here is not as it should be.

[SelaseKay]

Hi @large, after reviewing the code handling subscribeToTopic, I noticed that errors are correctly managed, as shown here. As you mentioned, this behavior originates from the native SDK. It appears that the error is not being thrown, as seen here, which prevents us from rethrowing it for users to handle.

[large]

Nice dive into the native SDK, could not find it myself earlier.
I do not know how error-regime for this package is, but throwing an error instead of logging is pretty normal?
Should this case be asked to the native-android team maybe?

The task that actually resync by it self is not the biggest issue.
But here it will just stod: https://github.com/firebase/firebase-android-sdk/blob/8e61ec2d84f42229f4b0d09fd144237b63b547a7/firebase-messaging/src/main/java/com/google/firebase/messaging/TopicsSyncTask.java#L106-L117

Maybe the function isDeviceConnected() should be implemented into fluttermessaging: https://github.com/firebase/firebase-android-sdk/blob/8e61ec2d84f42229f4b0d09fd144237b63b547a7/firebase-messaging/src/main/java/com/google/firebase/messaging/TopicsSyncTask.java#L121-L126

So it possible to know if we are connected or not?