Uniqueness of WordPress user_login field

[sweber83]

Checklist

• I have looked into the Readme and the documentation, and have not found a suitable solution or answer.
• I have searched the issues and have not found a suitable solution or answer.
• I have searched the Auth0 Community forums and have not found a suitable solution or answer.
• I agree to the terms within the Auth0 Code of Conduct.

Description

When a user registers/logs in for the first time, and the Authentication->onLogin() method is called, it calls Authentication->resolveIdentity() which then creates a new WordPress user.
If the users email address was already verified, the part of the email, before the @ is used as the user_login.

wordpress/src/Actions/Authentication.php

Line 704 in 169e917

$username = (null !== $email) ? explode('@', $email, 2)[0] : explode('|', $sub ?? '', 2)[1];

If two users register, where the part of the email before the @ is identical, no user is created the second time (wp_create_user() returns a WP_Error instance).

What is the reason for doing it this way?
It's an obvious issue.

Reproduction

1. Register with user [email protected]
2. Register with user [email protected]
3. The second user is not created because a user with the user_login "a" already exists

Additional context

No response

wp-auth0 version

5.2.1

WordPress version

6.7.1

PHP version

8.2.24

[jmossuow]

I can confirm this issue. This was causing a no creation issue for us as well the uniqueness of this username field is fundamentally wrong. and if there is a wp error on creation there is no attempt to add like maybe a number on the end a random int and try again. Causes the user to constantly be put in loop when trying to log in. As soon as you add the user in manually they are logged in just fine.