discourse/discourse — pull request #3030 by longhotsummer (2014-12-08 10:44:41+00:00)
Title: Facebook auth without an email should allow user to enter email

In some cases Facebook doesn't send back a user's email. In this
case, allow the user to enter their email address.

See
https://meta.discourse.org/t/facebook-initial-login-create-account-dialog-leaves-email-field-blank/13815/15