[Distutils] [buildout] selectively excluding site-packages

[Gary Poster]

On Mar 19, 2010, at 6:27 AM, Chris Withers wrote:

> Gary Poster wrote:
>> On Mar 17, 2010, at 5:39 AM, Chris Withers wrote:
>>> Hi Guys,
>>> 
>>> I guess this is mainly aimed at Jim and Gary...
>>> 
>>> How's the work to allow control over which packages come from site-packages and whether or not site-packages is considered by default?
>> Jim asked if I tested all branches with all pertinent Python versions.  After almost two weeks, I replied "no."  Only the branches that I considered deploying internally were tested in that way.  I haven't heard if Jim wants me to make all branches pass that way, but I offered.
> 
> Ah, I thought you'd rolled all the branches up into one uber-branch?

Each branch builds on the previous one, so that's pretty much true.

(I am keeping the bzr branch lp:~gary/zc.buildout/python-support up-to-date with both trunk and my branches, but that's really more of an internal artifact.)

>> From my perspective, sure.  Use the most recent branch and report problems.  I'm sure there will be some.  I need to make bootstrap more defensive, for instance.  Maybe I'll have time for that today.
>> bzr branch is lp:~gary/zc.buildout/python-support-8-support-subprocess and svn is http://svn.zope.org/repos/main/zc.buildout/branches/gary-8/ .
> 
> Okay, I'll see what I can do...
> 
> Are these any docs on the new features on that branch? If so, where should I look?

The user-visible part of the changes is in the z3c.recipe.scripts recipe contained within the zc.buildout checkout, like zc.recipe.egg.  zc.recipe.egg has no user-visible changes and works mostly as before, providing hopefully full backwards compatibility.  z3c.recipe.scripts has the logic to work with a Python that might have some site-packages hanging around.

http://svn.zope.org/zc.buildout/branches/gary-8/z3c.recipe.scripts_/src/z3c/recipe/scripts/README.txt?view=auto

Note that mixing a system python's site-packages and buildout eggs will, in my guess, always be less stable than trying to simply use a system Python without site-packages at all (the default behavior of the new recipe).  See the discussion in the README file, which touches on the concerns but probably does not go far enough.  That said, for "hysterical" reasons, I'm using the mixing approach right now myself.

Gary