[arch-dev-public] [RFC] Python 3.3.0 and PEP 394

Allan McRae allan at archlinux.org
Thu Sep 13 00:18:34 EDT 2012

On 13/09/12 10:00, Stéphane Gaudreault wrote:
> Python 3.3.0 should be released around September 22. I would like to
> take this opportunity to implement some of the recommendations of the
> PEP 394 [1]. This PEP was mostly done in reaction to what Arch did to
> the /usr/bin/python symlink (in summary, most python devs are against
> the move to python3 as a default at this time).
> In short:
> python2 should refer to some version of Python 2.x
> python3 should refer to some version of Python 3.x
> python should refer to the same target as python2 but may refer to
> python3 on some bleeding edge distributions
> This means that we should never have a reference to '#!/usr/bin/python'
> in any of our packages. All those reference should be changed to
> /usr/bin/python2 to refer to Python 2.x and /usr/bin/python3 for Python
> 3.x. The idea here is that a system without any python symlink should
> work without problem. Maybe namcap could be used to detect wrong shebang ?

This is necessary as far as I am concerned.

> Another possibility, suggested by Allan, would be to go even further and
> use /usr/bin/python3.3 and /usr/bin/python2.7 for all shebangs. Then
> /usr/bin/python can point to any version and /usr/bin/python2 and
> /usr/bin/python3 can point to any pyhton2.x and python3.x respectively.
> These numbers in the shebangs will be changed when python bump is
> version number as we need to rebuild almost everything anyway.

I'm leaning towards that being to much effort.  Just using
python2/python3 should be enough.

One thing not mentioned in this email is that we really need to sort out
the package naming in the repos.  Two options:




I personally would go for the first option, under the assumption that
python4 will not exist for many years.


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