Google Sign-In throws an exception on Android, while it works as expected on iOS

[ronmara]

Issue Summary
Google Sign-In throws an exception on Android, while it works as expected on iOS.

Steps to Reproduce
Calling the following line on Android triggers the exception:

GoogleSignIn.DefaultInstance.SignIn().ContinueWith(OnAuthenticationFinished, TaskScheduler.FromCurrentSynchronizationContext());

Observed Behavior
On Android, the following exception is thrown:

System.TypeInitializationException: The type initializer for 'Google.Impl.GoogleSignInImpl' threw an exception.
---> UnityEngine.AndroidJavaException: java.lang.ClassNotFoundException: com.google.googlesignin.GoogleSignInHelper

Expected Behavior
Google Sign-In should work correctly on Android, as it does on iOS.

Environment
Unity Version: 6000.1.4f1

Additional Context
If relevant, the app is also using Firebase and initializing it on startup with the following code:

await FirebaseApp.CheckAndFixDependenciesAsync().ContinueWith(task =>
{
    var dependencyStatus = task.Result;
    if (dependencyStatus == DependencyStatus.Available)
    {
        FirebaseAnalytics.SetAnalyticsCollectionEnabled(true);
        FirebaseApp app = FirebaseApp.DefaultInstance;
        Crashlytics.ReportUncaughtExceptionsAsFatal = true;
        IsFirebaseIntialized = true;
    }
    else
    {
        Debug.LogError($"Could not resolve all Firebase dependencies: {dependencyStatus}");
        IsFirebaseIntialized = false;
    }
});

[Thaina]

If there is ClassNotFoundException I would suspect proguard and other kind of type removal optimization

Could you please check if there are any of that enabled?

[Thaina]

Another possibility is conflict dependency of multiple library. Have you success build your signin system app from pure new project with only google signin package first? then move on to add other package and see what might be conflicted?

[ronmara]

I removed the release minification, and everything is working properly again

[Thaina]

Great

I think you can enabled minify. But it need to add all the class required with proguard which I don't know the exact configuration