pypa/pip — pull request #1216 by pfmoore (2013-10-01 19:37:32+00:00)
Title: Modify wheel check for setuptools to work with setuptools zip file

The current check for setuptools in pip/wheel.py fails if setuptools is being imported from a zip file (or wheel), because pkg_resources.find_distributions does not support zip files.

This patch falls back on importing setuptools and using its __version__ attribute if find_distrinutions fails.