[Python-Dev] Support the /usr/bin/python2 symlink upstream

[Allan McRae]

On 03/03/11 00:03, Piotr Ożarowski wrote:
> [Sandro Tosi, 2011-03-02]
>> On Wed, Mar 2, 2011 at 13:56, Piotr Ożarowski<piotr at debian.org>  wrote:
>>> [Sandro Tosi, 2011-03-02]
>>>> On Wed, Mar 2, 2011 at 10:01, Piotr Ożarowski<piotr at debian.org>  wrote:
>>>>> I co-maintain with Matthias a package that provides /usr/bin/python
>>>>> symlink in Debian and I can confirm that it will always point to Python
>>>>> 2.X. We also do not plan to add /usr/bin/python2 symlink (and I guess
>>>>> only accepted PEP can change that)
>>>>
>>>> Can you please explain why you NACK this proposed change?
>>>
>>> it encourages people to change /usr/bin/python symlink to point to
>>> python3.X which I'm strongly against (how can I tell that upstream
>>> author meant python3.X and not python2.X without checking the code?)
>>
>> with 'people' do you mean 'users'? if so, isn't this risk already present?
>
> users already break their systems via "sudo ez_install ..." (note the
> "sudo" part!), I meant developers (distro and upstream authors).
> If a programmer develops a script in Python 3 on Arch and later ships
> his file with /usr/bin/python in shebang, it's very likely that this
> script will not work on all distributions that didn't (yet?) change the
> symlink.
>
>> If you, user, change the python symlink (provided by python-minimal in
>> Debian) to something else than what's shipped, it's still a local
>> change, and will never be supported; but with python2 *Debian is free*
>> to decide if python can be pointed to python3, if the time will come.
>
> ... and make other distributions developers' life miserable?

But is that not the whole point of adding the /usr/bin/python2 symlink. 
  That way a developer can explicitly use a /usr/bin/python2 or 
/usr/bin/python3 shebang and have it portable everywhere.  At the 
moment, Debian seems to be the major hold-up on that actually being a 
reality being the only major distro I could find that does not provide 
such a symlink.

Note also that even restricting /usr/bin/python to point at a python-2.x 
binary gives no guarantee on what actual python-2.x version you are 
getting, so it is not as if guaranteeing portability is not a problem 
already...

Allan