title: Firebase Allowing Multiple Accounts from Same Email Address
body: <p>Within the Firebase console I have specifically set it to only allow "One account per email address".  This is found on the sign-in method tab under "advanced".  </p>
  
  <p>I have an account created using the Google login method that has an address like "me@gmail.com".  If I then choose to sign-in via Facebook using an account that also uses "me@gmail.com", Firebase is allowing it with the exception that the email address in the Users entity is null. </p>
  
  <p>The Firebase documentation states:</p>
  
  <blockquote>
    <p>if you don't allow multiple accounts with the same email address, a
    user cannot create a new account that signs in using a Google Account
    with the email address ex@gmail.com if there already is an account
    that signs in using the email address ex@gmail.com and a password.</p>
  </blockquote>
  
  <p>Does this only count if you are trying to create a Firebase login directly with a username/password vs creating an account from two providers like Facebook and Google?  I would be under the impression that if it finds a duplicate email address it should reject the registration/login.  I do realize the quote states "and a password" which makes me wonder.</p>