Manage an 'account-exists-with-different-credential' AuthFailed exception?

[jeanmatthieud]

I want to manage an 'account-exists-with-different-credential' error during sign-in.

To produce this error (on Android):

• The user have the address [email protected]
• The uses this email address for a Facebook account (logged in in the Facebook app)
• The user uses an app with a SignInScreen, with two providers: Google and Facebook
• The user creates an account in this app with the Google provider
• The user log out
• The user tries to log in with the Facebook provider

The callback AuthStateChangeAction<AuthFailed> is called, with a FirebaseAuthException, with the error code account-exists-with-different-credential.

The fields email AND credentials of the FirebaseAuthException are empty.
The official Firebase documentation explains that we have to use the email address and the credential. But those data are not available in the AuthFailed callback:

I don't know if it's a Firebase bug or a FirebaseUi issue.

I'm using the latest package versions:

• firebase_ui_auth: ^1.6.5
• firebase_ui_localizations: ^1.5.3
• flutter_facebook_auth: ^6.0.1
• google_sign_in: ^6.1.4
• firebase_ui_oauth_apple: ^1.2.9
• firebase_ui_oauth_facebook: ^1.2.9
• firebase_ui_oauth_google: ^1.2.9

[lesnitsky]

You can handle this using AuthStateChangeAction<DifferentSignInMethodsFound>.

AuthStateChangeAction<DifferentSignInMethodsFound>((context, state) {
  final methods = state.methods; // an array of all provider id's associated with the email
  // your custom logic here
});

If you're using SignInScreen, you can pass this actions to actions list.

If you're building more customized UI – wrap your widget tree with FirebaseUIAction:

FirebaseUIActions(
  actions: [
    AuthStateChangeAction<DifferentSignInMethodsFound>(handler),
  ],
  child: yourWidget,
);

There's also showDifferentMethodSignInDialog that will show relevant UI for given providers, so it could be used to handle this scenario.