github omniauth authentication fails with HTTP 500 if no mail is made public on github account

Created by: dolanor

I use my mail in gravatar information in my profile, but I don't publish my email publicly on github. Trying to authenticate with github on my gitlab instance failed because of that but didn't express it really good.

    500

    We're sorry, but something went wrong.

    We've been notified about this issue and we'll take a look at it shortly.

And now that I added my mail temporarily publicly on my github account, test it to make it work and then removed it, the connection with github to my gitlab works, even if the github account doesn't display my mail publicly.

The way to reproduce is :

• requirement : Github account with no mail filled except for gravatar
• Try to connect to gitlab with the github signin auth : Error 500
• On github, add a mail in the public mail input, save
• Try to connect to gitlab with the github signin auth : successful.
  • If the signin connects you to gitlab (if your user is not blocked by gitlab SSO by default), disconnect
• On github, remove the mail in the public mail input, save
• Try to connect to gitlab with the github signin auth successful.