Proposal to disable "Avoid Duplicates" on all ceph.io lists - ceph-users

4 Sep 2019

Hello,

Yesterday I copied dgallowa in "Heavily-linked lists.ceph.com
pipermail archive now appears to lead to 404s" on ceph-users, but one
of the subscribers reached out to me saying that they do not see him on
the CC.

This looks like a feature of mailman that has bitten others before:

https://lists.gnu.org/archive/html/qemu-devel/2015-06/msg02639.html

...
   mailman has an
(extremely annoying, in my opinion) habit of munging cc:
 lines to drop the name of any recipient who has set their list delivery
 options to avoid duplicate messages where the recipient is in cc.
 Ultimately, the end user still gets the messages (reply-to-all gets the
 message back to the list, even though it drops the cc), but at the
 expense of not directly going to the inbox as desired.  At least I still
 only get one copy of the message, but yes, I'd rather have that one copy
 come directly to me for all messages in the thread, rather than through
 the list because I was munged out of cc.

 I hope that mailman3/hyperkitty will have saner defaults and not munge
 cc lists to exclude subscribers merely based on their preference on
 duplicate mail receipt. 
 Wow!  You are right:

 I checked my @redhat.com inbox and I see address@hidden has
 Kevin in CC.

 I checked my @gmail.com inbox (subscribed to mailing list) and I see
 address@hidden does not have Kevin in CC.

 I guess my @redhat.com email was received directly from Max because I
 was in CC list.  It didn't pass through Mailman.  I saw the original,
 unmodified list of CCs with Kevin included.

 The @gmail.com email was received from the mailing list.  Mailman did
 what you described.

 This means I cannot send "Please CC maintainer" emails anymore because
 I cannot be sure whether the maintainer was CCed! 
mailman3 that all ceph.io lists were transitioned to is apparently
slightly saner in that this functionality is implemented as a handler,
which can (hopefully!) be disabled by removing it from the pipeline:

  https://gitlab.com/mailman/mailman/blob/master/src/mailman/handlers/avoid_d…

https://gitlab.com/mailman/mailman/blob/master/src/mailman/handlers/docs/av…

I'm proposing that we disable this handler for all ceph.io lists.  It
confuses everyone and it's not clear if it is actually doing any good
to anyone.  gmail and other similar systems already deduplicate without
munging the headers for everyone and folks who are filtering locally
probably already have a generic rule for discarding duplicates.

IMO the mailing list software should never touch To or Cc.  Thoughts?

Thanks,

                Ilya