Multirelease effort: Moving to Python 3

[Toshio Kuratomi]

On Jul 25, 2013 12:13 AM, "Bohuslav Kabrda" <bkabrda at redhat.com> wrote:
>
> ----- Original Message -----
> > Since Python upstream really cares about these things, I started a
discussion
> > about this on their mailing list [1]. So far, it seems that people
prefer my
> > mental model, but this is judging from just 4 answers, 2 of which
mentioned
> > this. So let's wait and see.
> > BTW, if Python 2 and Python 3 were different languages, then IMO it
wouldn't
> > make sense to point /usr/bin/python to Python 3, while upstream plans to
> > actually give the recommendation to do so sometime in the future.
> >
>
> So, judging from what upstream has recommended (and how they will modify
pep 394), we should:
> - Mandate usage of /usr/bin/python2 and prohibit usage of /usr/bin/python
(I think this can be done automatically in %__os_install_post, or somewhere
similar) - we should probably do that ASAP

<nod>.  Which means patching in a bunch of packages.  For os_install_post
modification you're talking about a check that fails the build if
/usr/bin/python is used?  I note that upstream envisions some cases where
/usr/bin/python is correct but I don't recall any package where we'd have
invoked that clause (the case is when the code will run on either python2
or on python3)

/me goes to the upstream thread to ask Nick what distutils/setuptools/etc
do when they rewrite shebang lines.

> - Rename python to python2 and add "Provides: python" for the time being
(the similar should probably be done for all python packages to keep things
consistent) - we can do this for F21

Renaming other packages gets problematic.  See the previous discussion on
python-devel at lists.fp.o that tomspur championed.  (This was one of the
items I was hoping could be discussed at flock) You wouldn't expect to
report bugs for the python3-foo library against the python2-foo package for
instance.  One possibility that we talked about was to stop shipping
python3 packages as subpackages of the python2 modules.

> - Somewhere in the future switch "Provides: python" to python3 stuff and
possibly /usr/bin/python to point to python3, according to upstream
recommendation (2015?) to keep consistent across multiple platforms as much
as possible.
>

Rather than 2015 I'd tie it to when upstream switches the recommendation in
pep 394.

-Toshio
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