[aur-general] [arch-dev-public] Python-3.x transition with python-2.7 update

[Stephen Weinberg]

On Tue, 06 Jul 2010 23:25:15 +1000
Allan McRae <allan at archlinux.org> wrote:

> On 06/07/10 22:54, Gergely Imreh wrote:
> > On 6 July 2010 20:09, Ng Oon-Ee<ngoonee at gmail.com>  wrote:
> >> On Tue, 2010-07-06 at 10:51 +0200, Lukáš Jirkovský wrote:
> >>> On 6 July 2010 10:19, Isaac
> >>> Dupree<ml at isaac.cedarswampstudios.org>  wrote:
> >>>> On 07/06/10 01:57, Lukáš Jirkovský wrote:
> >>>>>
> >>>>> Hello Allan,
> >>>>> I know that I'm just a regular user but I'd like to express my
> >>>>> opinion too. I think the transition should be done when most
> >>>>> modules and applications support Python 3. I'd not be surprised
> >>>>> if the transition of majority of modules would take several
> >>>>> years. By that time there may be a way how to do a dual rename.
> >>>>
> >>>> Hi Lukas,
> >>>> Can you present a technical reason against doing the renaming
> >>>> now? Because as far as I can see, Allan has worked out the kinks
> >>>> and it will actually not harm you as a regular user at all...
> >>>>
> >>>> (unless you write personal scripts in python that you want to
> >>>> work with #!something on multiple distros? (then you probably
> >>>> want to run them in python version 2) .. I'm not sure I can
> >>>> think of an easy way to do that; maybe for each distro you use
> >>>> you could put a symlink in /usr/local/bin/python2 for example.)
> >>>>
> >>>> -Isaac
> >>>>
> >>>
> >>> Hi Isaac,
> >>> I don't write Python scripts but yeah, I think this is a real
> >>> problem. The other problem is that there are not many users of
> >>> python 3 out there.
> >>>
> >>> In a more subjective way I think whenever something is set as
> >>> default it should be the one which has most users (in both terms
> >>> of people and software).
> >>>
> >>> Lukas
> >>
> >> As another user (who doesn't write Python), I'd state that
> >> 'majority usage' is a pretty poor guideline for users of a Linux
> >> distro, and a relatively small one at that.
> >>
> >> I'm all for the option which reduces workload on the packagers. Of
> >> course if things break big-time then it may be a problem, but
> >> that's what [testing] is for, and those of us using it should know
> >> what to do if/when breakage occurs.
> >>
> >>
> >
> >
> > Some more background info for those who are not that familiar why
> > the Python 2 vs. 3 is such a big problem (there seem to plenty of
> > people, and sorry for the ones who already know this inside out):
> > http://wiki.python.org/moin/Python2orPython3
> >
> >> From that page:
> > "Popular modules that don't yet support Python 3 include Twisted
> > (for networking and a bunch of other stuff), gevent (like Twisted
> > but different), Django and Pylons (for building websites), PyGTK and
> > PySide (for making GUIs), py2exe (for packaging your application for
> > Windows users), PIL (for processing images), numpy (for number
> > crunching)..."
> >
> > Thus I would mind a rebuild less, than losing my daily
> > numpy/scipy/PyGTK...
> 
> Do you seriously think would be removing those from the repos?  That 
> would be insane...
> 
> numpy/scipy/pygtk/etc will all be in the repos and working.  The only 
> thing you will have to do is use "#!/usr/bin/env python2.7" (or just 
> python2) at the start of your script.
> 
> Allan
> 
> 
> 

At the moment most programs don't know to use #!/usr/bin/env python2.
Therefore many python programs that users will download will not work
without modification (although a very small modification). I do not
think it is time yet. I do not believe that there is a large enough
group of users of python3 to make it the default.

Please note that unlike everyone else who has commented, I do a lot of
python development. It would not affect me personally. I have already
figured out that my script will work more smoothly in the future if I
use "python2" over "python".

Is there a good reason to ever switch python to python3? The option of
just not switching at all has never come up. At some point we would
need to move everything over, but why not continue to call it python3?