UIHandler.firebaseInitialized is never read in the example projects - questions arise

[broersma]

Please fill in the following fields:

Unity editor version: 2018.2.17f1 Firebase Unity SDK version: 5.4.4 Additional SDKs you are using (Facebook, AdMob, etc.): Platform you are using the Unity editor on (Mac, Windows, or Linux): Windows Platform you are targeting (iOS, Android, and/or desktop): iOS, Android

Please describe the issue here:

Several testapps in this repository define a firebaseInitialized field in the UIHandler MonoBehaviour (https://github.com/firebase/quickstart-unity/search?q=firebaseInitialized&unscoped_q=firebaseInitialized). Presumably this is the "flag here to indicate whether Firebase is ready to use by your app" you should set after FirebaseApp.CheckAndFixDependenciesAsync results in DependencyStatus.Available as per https://firebase.google.com/docs/unity/setup#confirm_google_play_version.

This firebaseInitialized field however seems to be unread in the code in the samples. So why is it there in the first place?

Now, I have tried searching far and wide but nowhere I can find anything more definitive than a vague warning that "Firebase Unity SDK is not safe to use" if FirebaseApp.CheckAndFixDependenciesAsync isn't called or doesn't result in DependencyStatus.Available.

So, what bad stuff will actually happen if the dependencies cannot or aren't succesfully checked and fixed?

1. Will my app crash when I call, e.g., FirebaseAnalytics.LogEvent?
2. Or does it make Firebase Auth (or some other feature) fail/not work without interfering with the rest of the app?
3. Do I actually need to guard all calls in to Firebase with an if (firebaseInitialized)? (Or is that not really necessary, like in the samples in this repo?)

Please answer the following, if applicable:

Have you been able to reproduce this issue with just the Firebase Unity quickstarts (this GitHub project)? Yes, trivially. :-)

[jonsimantov]

You should wait for FirebaseApp.CheckAndFixDependenciesAsync to successfully finish before calling any other Firebase methods. In most cases it will finish very quickly. In many cases, calling other Firebase functions while CheckAndFixDependenciesAsync is still running will throw an exception.

You can cause CheckAndFixDependenciesAsync to take a long time by reverting the Google Play services app (on Android) to the factory installed version. This will cause CheckAndFixDependenciesAsync to prompt you to update Google Play services, and it won't complete until the update is finished.

Some of the quickstarts do define a "firebaseInitialized" that is used by our internal tests, but the interactive quickstarts don't read that field. You should still make sure not to call Firebase functions before CheckAndFixDependenciesAsync finishes, though.

[broersma]

You can cause CheckAndFixDependenciesAsync to take a long time by reverting the Google Play services app (on Android) to the factory installed version. This will cause CheckAndFixDependenciesAsync to prompt you to update Google Play services, and it won't complete until the update is finished.

Thanks, that sounds quite useful! However, when I do this (on ancient (?) Android 6.0.1), it downgrades Google Play Services from 15.0.90 to 9.8.79, but when I run my app it seems like CheckAndFixDependenciesAsync thinks everything is ok (while I do get notifications from Google Maps complaining about Google Play Services being outdated). Should 9.8.79 be good enough for Firebase?

Regardless, it seems the usage pattern here is to call CheckAndFixDependenciesAsync during loading screen from a DontDestroyOnLoaded gameobject, while keeping guard clauses with firebaseInitialized (or similar) around any calls to the actual Firebase functions. In this way, users without connectivity or a without a desire to update Google Play Service could still keep on using the app (even though Firebase might not function). Did I overlook anything?

[broersma]

but when I run my app it seems like CheckAndFixDependenciesAsync thinks everything is ok

Hmm, curiously, I even get this behaviour when I disable Google Play Services. So, while Google Maps complains about Google Play Services being disabled, CheckAndFixDependenciesAsync seems to return with Firebase.DependencyStatus.Available and I can see my app casually logging analytics events to the Firebase console's DebugView.

[stewartmiles]

@broersma it depends upon the Firebase SDK version you're using since each SDK is a client to Google Play Services at a particular version and above. So if you're using a really old SDK then it's possible Firebase is happy while other parts of the system are not.

In your case, it depends upon the modules you're using. Some components of Firebase do not require Google Play Services see https://firebase.google.com/docs/cpp/setup#requiring_google_play_services