At 07:01 PM 3/17/2007 -0400, Jim Fulton wrote:

I want to get a list of all of the distributions I can find that satisfy a requirement. I've found the following works:

index.obtain(requirement) dists = [d for d in index[requirement.project_name] if d in requirement]

where index is a setuptools.package_index.PackageIndex.

Is there a better way?

There are other ways, but the above is the simplest and most direct way, given your use case. Normally, performing a resolve() or require() on a working set will end up invoking obtain() indirectly, if a requirement can't otherwise be met -- this allows network access to be lazy, so it's not done unless it's really needed.

The obtain call seems to be necessary to initialize the index for the given project.

Yes - Environment normally calls 'obtain()' in response to a 'best_match()' operation, which is in turn called by a WorkingSet's 'resolve()' method. The idea is that you can subclass Environment (in this case, to create a PackageIndex) and override 'obtain()' to find packages in locations that are not part of the working set used to create the Environment.