[PATCH 3 of 6] packaging: upgrade Debian packaging to build with Python 3

[Yuya Nishihara]

On Mon, 21 Oct 2019 09:01:51 -0700, Gregory Szorc wrote:
> On Mon, Oct 21, 2019 at 6:57 AM Yuya Nishihara <yuya at tcha.org> wrote:
> > On Mon, 21 Oct 2019 12:00:55 +0200, Denis Laxalde wrote:
> > > # HG changeset patch
> > > # User Denis Laxalde <denis at laxalde.org>
> > > # Date 1571648394 -7200
> > > #      Mon Oct 21 10:59:54 2019 +0200
> > > # Node ID 09f95d7a20c6d2e0bf6218e2a5bc9cd2b803c8ec
> > > # Parent  70764c9ddba397fa6cc2c92a28a1a65c5bdddaea
> > > packaging: upgrade Debian packaging to build with Python 3
> > >
> > > Also drop the explicit "Depends: python" as debhelper will add it.
> >
> > So, are we ready to ship py3 version as stable?
> > I know it's planned for 5.2, but I have no idea about the current state.
> >
> 
> We ideally produce Python 2 and Python 3 package variants. Then we switch
> to Python 3 exclusive in a future release.
> 
> For Debian packaging, this could be a bit more difficult, as I believe we'd
> need to fork the Debian packaging templates in the repository.

Maybe python-mercurial package can be split off so we can generate both
python-mercurial and python3-mercurial. The main mercurial package will have
to depend on one of these, but we can at least run python|python3 /usr/bin/hg.

That might also apply to tortoisehg, which py3 support is highly unstable.

> I doubt the in-repo Debian packaging is used that much. So I could go
> either way with regards to transitioning the packaging to Python 3
> exclusive. Definitely safer to hold off.

Seems fine so long as our package isn't advertised as stable one.