[Python-Dev] 3.1 focus (was Re: for __future__ import planning)

[Tarek Ziadé]

On Sat, Oct 4, 2008 at 2:22 PM, "Martin v. Löwis" <martin at v.loewis.de> wrote:
> Antoine Pitrou wrote:
>> Martin v. Löwis <martin <at> v.loewis.de> writes:
>>>> This may be more complicated than it sounds, because you'd probably
>>>> add a very general requirement-indicating feature to PyPI, not merely
>>>> a 'supports 3.0' Boolean on each record, and requirements are actually
>>>> pretty complicated: alternative packages, specific version numbers...
>>> Can you propose a spec?
>>
>> Setuptools already has a syntax for declaring requirements.
>> http://peak.telecommunity.com/DevCenter/setuptools#declaring-dependencies
>
> That is underspecified for the issue at hand: What *specifically* should
> PyPI look for to determine 3.0 support in a package, and how
> *specifically* should it display that?
>
> An alternative to specifying dependencies would be to specify a
> classifier, e.g.
>
>  Programming Language :: Python :: 3
>
> or
>
>  Programming Langauge :: Python3
>
> Then, no changes to PyPI are needed (except for adding the classifier to
> the database), and searching for Python-3-supporting packages could
> go through http://pypi.python.org/pypi?%3Aaction=browse

Setuptools declares dependencies, but does not add a Python version requirement,
like what was proposed in PEP 345 (http://www.python.org/dev/peps/pep-0345/)
with a new metadata called 'Requires Python'

Even if the problem is fixed in short term with a Trove classifier, the metadata
of a package should provide this information imho.

>From there PyPI should be able to provide the Python version directly.

For a full list of dependencies this is another tough problem due to the dynamic
nature of the metadata: you have to run setup.py to get the list of dependencies
because they are determined by code. This is by design, and plans for
a refactoring are
being discussed in distutils-SIG since a few days.

In any case, extending metadata with supported Python version could
be a first simple, useful step to do in distutils and PyPI today. So
the Python version
comes as the same level than the Platform or the License.


Tarek