Changes in Guidelines Connected to "Python 3 as Default" Change

[Bohuslav Kabrda]

Hi all,
as you are well aware, there is the "Python 3 as Default" change proposed for F22 [1]. There are several guideline changes that will need to be done and some that may be done in order to improve the situation. I'd like to make this thread a sort of brainstorming on my thoughts as well as possibility for anyone to add something that should be done as well. After that, I'm planning to open an FPC ticket with all the gathered and discussed changes that will come up on this thread.

So here are my proposals for changes in current guidelines [2]:
- In [3], it says "If the executables provide the same functionality independent of whether they are run on top of Python 2 or Python 3, then only one version of the executable should be packaged. Currently it will be the python 2 implementation, but once the Python 3 implementation is proven to work, the executable can be retired from the python 2 build and enabled in the python 3 package." - this should be changed to prefer Python 3
- (This is not really related to the switch, but more of a general remark) In [4], it says that "python 3 version of the executable gains a python3- prefix". This is IMO bad, since upstream projects tend to name the versioned binaries "foo-3.4, foo-3" or "foo3.4, foo3". We should accept one of these - I'm not really certain which one of them. I tried to discuss this several times on distutils-sig mailing list, but without reaching a consensus. Either way, prefixing with python3- doesn't make sense to me, because it's not similar to any upstream way and you don't find the binaries under their names using tab completion (e.g. foo<tab> doesn't tell you about python3-foo).
- As for binaries/scripts in /usr/bin (assuming there are both python2 and python3 versions), the unversioned files should point to python2 version. This aligns with /usr/bin/python still pointing to python2.
- Some time ago, I also put together a proposal for some larger changes in Python packaging [5], mostly in how the subpackages for different interpreters should be done. I opened an FPC ticket [6] to get some comments and it seemed that FPC was favorable. While I still think it'd be great to do this change, it'll require a significant effort and that is better spent helping upstreams to port to Python 3 ATM. So I'd also like to receive more comments on this proposal, although I think we should postpone it to F23 (or maybe even later).

Thanks for all your comments and further suggestions.

Slavek


[1] http://fedoraproject.org/wiki/Changes/Python_3_as_Default
[2] http://fedoraproject.org/wiki/Packaging:Python
[3] http://fedoraproject.org/wiki/Packaging:Python#Guidelines
[4] http://fedoraproject.org/wiki/Packaging:Python#Naming
[5] https://fedoraproject.org/wiki/User:Bkabrda/Py2to3GuidelineChanges
[6] https://fedorahosted.org/fpc/ticket/379