This has the benefit that we now get the usual data about the
user/request/etc. in error emails related to bugdown exceptions;
previously we were just getting the traceback in the emails (since our
`mail_admins` template was very simple) and no other debugging
details.
Comments tweaked by tabbott to help make clear exactly what's going on
here, since it's a little subtle and a little hacky.
Fixes#8843.
When I added this "Deployed code" feature to the error reporting,
I apparently hadn't worked out enough of how this code works to
realize that `notify_server_error` may be in a different process,
at a different time and potentially even on a different machine
from the actual error being reported.
Given that architecture, all the data about the error must be computed
in `AdminNotifyHandler`, before sending the report through the queue,
or else it risks being wrong. The job of `notify_server_error` and
friends is only to format the data and send it off. So, move the
implementation of this feature in order to do that.
(@showell added some "nocoverage" directives here for code that
is hard to test (exceptions being thrown, deployment files not
existing) and that was originally part of a file that didn't
require 100% coverage)
This helps prevent them from diverging and getting different sets of
features and fixes. As a bonus, the email path gets a nice tweak that
the Zulip path has had for years, since f7f2ec0ac, which makes the
emails clearer and less broken-looking when logging a message with no
stack trace.