title: Firebase Overwrites Signin with Google Account
body: <p>There doesn't seem to be any mention of this in the documentation, and all I found was <a href="https://stackoverflow.com/questions/37619911/firebaseauthinvalidcredentialsexception-when-using-one-account-per-email-addres">this</a> and <a href="https://stackoverflow.com/questions/40718466/firebase-auth-not-throwing-user-collision-error-after-secondary-google-sign-in?rq=1">this</a>, where I would like to confirm this: </p>
  
  <blockquote>
    <p>If there is an existing account with the same email address but
    created with other credentials (e.g. password or non-trusted
    provider), the previous credentials are removed for security reasons.</p>
  </blockquote>
  
  <p>If a user signs in through Facebook or email/password and later through Google, their account sign in method is converted to Google. It only happens with Google and the setting for one account only is active.</p>
  
  <p>Is it intended to be like this and is there any way to stop it?</p>