Google Sign in fails on iOS 13 GM

Following is the solution for successfully having the login view. Call the signin method after the ViewController's view is appeared, it will not be dismissed programatically. I have just implemented in IOS 13 and it works fine.

override func viewDidAppear(_ animated: Bool) {
    super.viewDidAppear(animated)
    GIDSignIn.sharedInstance()?.delegate = self
    GIDSignIn.sharedInstance()?.presentingViewController = self
    GIDSignIn.sharedInstance()?.scopes = [kGTLRAuthScopeDrive]
    GIDSignIn.sharedInstance()?.prepareForInterfaceBuilder()
    GIDSignIn.sharedInstance()?.signIn()
}

I figured it out! The AppAuth-iOS, which is a open-source dependency of GoogleSignIn SDK, has been updated from 1.1.0 to 1.2.0 in August, including this iOS 13 support. So you need to run pod update GoogleSignIn to update the AppAuth to 1.2.0. The GoogleSignIn SDK itself hasn't been updated since 5.0.0, so that got me confused.

For future reference when other users find this question:

Google fixed this issue in GoogleSignIn v5.0.1. When updating your app to iOS 13, you'll likely have to update the GoogleSignIn SDK as well.

I downloaded the Firebase 6.9.0 SDK zip and experienced this same issue. The README indicated that the bundled version of AppAuth was 1.2.0. I was able to resolve it by updating AppAuth to the master version.

Specifically, I removed the AppAuth framework included with Firebase, and instead build AppAuth using Carthage.