A detailed description on virtualenv's packaging dependecies? (pip, easy_install, wheel, setuptools, distlib, etc.)

[haraldnordgren at gmail.com]

I was working on a bugfix for Virtualenv, regarding very long shebang lines that are breaking things. In the process, I realized that if I want really fix to my particular issue it likely needs to be done on the lower level of Python package management. I started with pip, moved to setuptools and now set my sight on distlib.

Can someone describe the specific dependencies of all the *packaging* libraries that `virtualenv` uses? And the dependencies between them?

I believe that virtualenv directly imports `pip`, `easy_install` and `wheel`. Those in turn import `setuptools` and `distlib`. Am I so lucky as to assume that distlib in the lowest-level library used by all the rest in virtualenv for packages?