Since #33751 was added `enqueue_retry.active_job` instrumentation to
the `retry_on` method, then #33897 moved the instrumentation to `retry_job`
method in order to ensure that this method publish `enqueue_retry.active_job`
notification too.
See related discussion https://github.com/rails/rails/pull/33751#discussion_r214140008
Since `enqueue_retry.active_job` moved to `retry_job`, there is no guarantee
that payload of `enqueue_retry.active_job` would have `:error`.
See test `LoggingTest#test_enqueue_retry_logging_on_retry_job` as
example of that case.
Related to https://github.com/rails/rails/pull/33897#discussion_r219707024
I think we can improve notification of `enqueue_retry.active_job`:
- If there is no `event.payload[:error]`, then publish like
"Retrying RescueJob in 3 seconds." only.
- If `event.payload[:wait]` is `nil`, then publish
"Retrying RescueJob in 0 seconds." instead of "Retrying RescueJob in nil seconds."
- If there is `event.payload[:error]`, then publish
"Retrying RescueJob in 3 seconds, due to a DefaultsError.".
- Change the type of the message from `error` to `info.`
Also, this commit removes part of messages - "The original exception was #{ex.cause.inspect}."
of `enqueue_retry.active_job`, `retry_stopped.active_job`, and `discard.active_job` since I
haven't found it useful. Please let me know whether you agree with that?
b0f2f5e348