On 30 June 2017 at 09:24, Adam Williamson <adamwill(a)fedoraproject.org> wrote:
On Thu, 2017-06-29 at 16:50 -0500, Jason L Tibbitts III wrote:
> > > > > > "AW" == Adam Williamson
<adamwill(a)fedoraproject.org> writes:
>
> AW> Right, that's a good point. *Why* exactly do we want to go to all
> AW> the trouble involved in making a switchover from 'python-foo'
> AW> meaning 'the Python 2 module called foo' to meaning 'the Python 3
> AW> module called foo'?
>
> It's about users. Once "python" means python3 (which is a decision
that
> the python upstream will eventually make), a user should be getting a
> python3 version when they type "dnf install python-foo".
>
> Packages should of course always specify the version and should never
> use python-* for anything unless there is no alternative. (Which is the
> what the current packaging guidelines state.)
That seems like, frankly, quite a weak justification for all the
trouble that's involved in migrating the 'meaning' of python-foo like
this (and, as Smooge pointed out, potentially doing it *again* for
Python 4, if it ever happens).
FWIW, our current expectation upstream is that the release after
Python 3.9 will be Python 3.10 (Guido overcame his historical aversion
to 2-digit version segments around the time that 2.7.10 became a
necessity).
Even if a 4.0 does happen, the magnitude of the change relative to the
preceding 3.x release is expected to be comparable to that between any
given 3.x and 3.x+1 release, so it wouldn't require the parallel stack
approach that has proven necessary to handle the core data model
changes that impacted the 2->3 transition.
So from that perspective, we (upstream) absolutely *do* want folks to
get back to using unqualified references to just "python". We just
first need redistributors to get to a point where the *current*
assumption is that otherwise unqualified references mean Python 3 (and
that's what the migration strategy proposed in
https://fedoraproject.org/wiki/FinalizingFedoraSwitchtoPython3
accomplishes).
Keep in mind that if we translate the target releases on the wiki page
to calendar dates:
* Fedora 30 ~= first half of 2019
* Fedora 32 ~= first half of 2020
So the currently proposed timeline for an unqualified "python-foo"
switching to meaning "python3-foo" is around the time where upstream
community support for Python 2.x ends.
Cheers,
Nick.
--
Nick Coghlan | ncoghlan(a)gmail.com | Brisbane, Australia