[Mailman-Developers] A question about OutgoingRunner and SMTPDirect

[Les Niles]

When SMTPDirect has a temporary delivery failure, it raises an
exception with a list of the failed recipients.  But OutgoingRunner
leaves the message queued with the original recipient list.
There's some logic in SMTPDirect to keep a list of undelivered
recipients, but AFAICT only when an exception is raised by the 
lower-level delivery function, which doesn't happen for these
temporary delivery failures.  (The particular failure we see,
pretty frequently, is a "450 -- enable to check MX record", for a
single recipient, which results in almost the entire list getting
the message over and over.)

Is this an oversight, or a design decision based on the behavior of
the smtp delivery mechanism?  If the former I'd be happy to fix it,
but if it's the latter I'd rather not waste my time nor break our
Mailman. :)

  -les