[Bug] iOS crashes when Google sign in is not enabled about firebase-unity-sdk

[a-maurice]

So, for an explanation on why this happens. The important part is that any of the OAuthProviders (like the Microsoft one) require adding the custom URL scheme to your XCode project's Info.plist, as documented here: https://firebase.google.com/docs/auth/ios/microsoft-oauth#handle_the_sign-in_flow_with_the_firebase_sdk

The Unity SDK tries to automate that step, by copying it from the REVERSED_CLIENT_ID in your GoogleServices-Info.plist, which is happening here:

firebase-unity-sdk/editor/app/src/XcodeProjectPatcher.cs

Line 421 in 289f094

// Read required data from the config file.

That is also where that error about how Google Sign-In will fail to initialize comes up.

Now I'm not sure why the REVERSED_CLIENT_ID seems to only be present in the GoogleServices-Info.plist when Google Sign-In is turned on, I can reach out to folks on my end about that part. I think there is also a CLIENT_ID, that one can derive the reversed version from if needed, so I can see if that is more likely to be present, and if so add some logic for that. At the very least, I can improve that error message, cause it is definitely missing that other things depend on that field as well.

[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.