Only generate email on push once for all recipients
The EmailsOnPushWorker
generates a new (identical) email for each recipient. This behaviour is in both CE and EE, although the code has diverged slightly:
- https://gitlab.com/gitlab-org/gitlab-ce/blob/master/app/workers/emails_on_push_worker.rb#L44
- https://gitlab.com/gitlab-org/gitlab-ee/blob/master/app/workers/emails_on_push_worker.rb#L47
As the email addresses are just passed straight through to the mailer - we don't verify that they belong to users with the correct access or anything like that - we don't need to perform the potentially expensive operation of generating an email body with diff highlighting, inline CSS, and so on for each recipient.
Related to #15137 (closed).