[Mailman-Developers] Python 3

Aurelien Bompard aurelien at bompard.org
Fri Dec 26 16:38:08 CET 2014

> One of my top priorities has been to port Mailman 3 (core) to Python 3.
> This
> work is now complete, and ready to be merged into trunk.  No doubt bugs
> still
> lurk, but at least the entire test suite is passing.

Congrats !

* A few database columns have changed from LargeBinary to Unicode.  I have
> not
>   yet figured out how to add the Alembic schema migrations to handle this,
> but
>   I'll do so before the release.

This should be pretty easy, something like the following command should
alembic -c src/mailman/config/alembic.cfg revision --autogenerate -m
"python3 port"

[...]  then I'll merge this to trunk and do a 3.0b5 release as a
> Python 3-only application.  Mailman 3 will not be bilingual so Python 2
> support will be dropped.

Wow. I am very surprised.
So we went from "Python3 compatibility is not on the blocker list for
Mailman 3.0" to "Mailman 3.0 will only work on Python 3".
That's quite a change.
This means I must now port HyperKitty and Kittystore to Python3, check that
we don't use Py2-only libraries, etc.
And mailman.client must be ported too, since it does import stuff from
mailman for testing purposes. I think Postorious is safe, but that must be
verified (I believe it imports the testing framework from mailman.client
and thus must be ported too).

And I thought the 3.0 release was almost there. I must say this is rather


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