'Firebase authentication provider silently changes from password to google.com
I use firebase authentication for my web app with three providers: email-password, google, or facebook. I have enabled the option "One account per email address".
When a user signs up using email-password (with a gmail address), then later uses google sign-in, I expect to receive an exception "auth/account-exists-with-different-credential", but I do not. His providerId is changed to google.com and he cannot use his password anymore (throws "auth/wrong-password").
Is this normal behaviour?
Solution 1:[1]
Firebase Authentication has a concept of a preferred provider for certain email addresses. The most common one is that google.com is the preferred provider for @gmail.com addresses, but I think they also exist for Facebook and Microsoft accounts.
If an existing account later signs up again from a preferred provider, that provider overwrites the existing user account. There is no way to change this behavior (that I know of).
Also see:
Solution 2:[2]
This is how I'm solving it: https://firebase.google.com/docs/auth/android/account-linking
Just link the "accounts".
Sources
This article follows the attribution requirements of Stack Overflow and is licensed under CC BY-SA 3.0.
Source: Stack Overflow
| Solution | Source |
|---|---|
| Solution 1 | Frank van Puffelen |
| Solution 2 | Binyamin Robbins |