[Python-Dev] PEP 382: Namespace Packages

[P.J. Eby]

At 02:52 PM 4/15/2009 -0400, A.M. Kuchling wrote:
>On Wed, Apr 15, 2009 at 01:59:34PM -0400, P.J. Eby wrote:
> > Please see the large number of Zope and PEAK distributions on PyPI as
> > minimal examples that disprove this being the common use case.  I expect
> > you will find a fair number of others, as well.
>    ...
> > In other words, the "base package" scenario is the exception these days,
> > not the rule.  I actually know specifically of only one other such
> > package besides your mx.* case, the logilab ll.* package.
>
>Isn't that pretty even, then?  zope.* and PEAK are two examples of one
>approach; and mx.* and ll.* are two examples that use the base package
>approach.  Neither approach seems to be the more common one, and both
>are pretty rare.

If you view the package listings on PyPI, you'll see that the "pure" 
namespaces currently in use include:

alchemist.*
amplecode.*
atomisator.*
bda.*
benri.*
beyondskins.*
bliptv.*
bopen.*
borg.*
bud.*
...

This is just going down to the 'b's, looking only at packages whose 
PyPI project name reflects a nested package name, and only including 
those with entries that:

1. use setuptools,
2. declare one or more namespace packages, and
3. do not depend on some sort of "base" or "core" package.

Technically, setuptools doesn't support base packages anyway, but if 
the organization appeared to be based on a "core+plugins/addons" 
model (as opposed to "collection of packages grouped in a namespace") 
I didn't include it in the list above -- i.e., I'm bending over 
backwards to be fair in the count.

If somebody wants to do a formal count of base vs. pure, it might 
provide interesting stats.  I initially only mentioned Zope and PEAK 
because I have direct knowledge of the developers' intent regarding 
their namespace packages.

However, now that I've actually looked at a tiny sample of PyPI, it's 
clear that the actual field use of pure namespace packages has 
positively exploded since setuptools made it practical to use them.

It's unclear, however, who is using base packages besides mx.* and 
ll.*, although I'd guess from the PyPI listings that perhaps Django 
is.  (It seems that "base" packages are more likely to use a 
'base-extension' naming pattern, vs. the 'namespace.project' pattern 
used by "pure" packages.)

Of course, I am certainly not opposed to supporting base packages, 
and Martin's version of PEP 382 is a plus for setuptools because it 
would allow setuptools to better support the "base" scenario.

But pure packages are definitely not a minority; in fact, a 
superficial observation of the full PyPI list suggests that there may 
be almost as many projects using pure-namespace packages, as there 
are non-namespaced projects!