Status of mailman3 in Jammy

[Paride Legovini]

Hi, about one month ago mailman3 has been removed from Jammy as it was
blocking migrations and because of its bad state in Debian [1].

mailman3 is in universe, however I think it's one of those packages we
want to keep keep an eye on, we even considered a MIR for it a few
cycles ago. Moreover mailman3 users upgrading from Focal to Jammy will
have their mailman3 setup broken by the newer (incompatible)
dependencies, which is not nice.

I checked what the blockers are to get mailman3 in better shape and
found out the following:

1. autopkgtest failures with newer versions of python-click

Debbug: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=997877

I believe this is fixed upstream version 3.3.5 by:

https://gitlab.com/mailman/mailman/-/commit/5d27492403f80c4b4ea1820b3

---

2. autopkgtest failures in the arc_validate tests

Debbug: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=996806

Fixed upstream by

https://gitlab.com/mailman/mailman/-/commit/f311b135fe13e3ec07ef2eedad

but this requires newer dependencies, in particular src:mistune (>=
2.0.0). Note that currently we have mistune 2.0.0-1+really0.8.4-1, so
there was an attempt to update it, but it was rolled back due to
reverse-dependencies not ready yet (per d/changelog). This is probably
not trivial to fix (transition).

---

3. autopkgtest fails with sqlalchemy 1.4.23+ds1

Debbug: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=995779
Upstream bug: https://gitlab.com/mailman/mailman/-/issues/845

This has been worked around upstream by requiring sqlalchemy <1.4, but
in Debian/Ubuntu that requirement can't be satisfied as we're already
ahead of that version. The upstream issue is still open, latest activity
is of 7 months ago. Not a straightforward fix.

---

I was hoping to kick mailman3 into shape with an ahead-of-Debian merge,
but this is not the case: this isn't a drive-by fixup.

Give where we are in the cycle we'll likely have to accept that "no
mailman3 in Jammy" will go into the release notes, and hopefully at some
point we'll be able to add it with a "new functionality SRU".

I wonder if we should do a mailman3 upload to Focal and Impish with
stricter versioned dependencies, so that upgrading to Jammy will require
explicitly removing mailman3, which is my opinion is better than
breaking it silently.

Paride

[1] https://bugs.launchpad.net/ubuntu/+source/mailman3/+bug/1960547