Authentication using Facebook at first and then Google causes an error in Firebase for Android

Question

As I understand from the Firebase Docs, if a user authenticates his account with a credential, he should strictly login by using the same credential if the credential is not

Answer 1

I finally ended with this logic:

If user try to sign in with Facebook, but user with given email already exist (with Google provider) and this errors occures:

"An account already exists with the same email address but different sign-in credentials. Sign in using a provider associated with this email address."

So, just ask user to loging using Google (and after it silently link Facebook to existing account)