If an exception was thrown inside `send_email` resulting in a retry,
we would include the `failed_tries` data in the event, which turned
out to thrown an exception itself.
This fixes that flow, including deepening the test so that it would
fail if we didn't have the new logic.
This commit just copies all the code from MissedMessageSendingWorker
class to a new EmailSendingWorker class. All the logic to send an email
through a queue was already there. This commit only makes the logic
generic. It does so by creating a special purpose queue called
'email_senders' to send any type of email. To make
MissedMessageSendingWorker still work we derive it from
EmailSendingWorker. All the tests that were testing
MissedMessageSendingWorker now run against EmailSendingWorker.
The original logic is buggy now that emails can belong to (and be
invited to) multiple realms.
The new logic in the `invites` queue worker also avoids the bug where
when the PreregistrationUser was gone by the time the queue worker got
to the invite (e.g., because it'd been revoked), we threw an exception.
[greg: fix upgrade-compatibility logic; add test; explain
revoked-invite race above]
This fixes a regression in 25c669df52.
We were draining the queue in both the superclass and the subclass,
so by the time the subclass started processing events, there were
no events to process. Now the subclass properly uses the events
passed in from the superclass.
The example_user() function is specifically designed for
AARON, hamlet, cordelia, and friends, and it allows a concise
way of using their built-in user profiles. Eventually, the
widespread use of example_user() should help us with refactorings
such as moving the tests users out of the "zulip.com" realm
and deprecating get_user_profile_by_email.