``.egg-info/PKG-INFO`` under revision control and put the project's source
code directly in the project directory.  If such a package had any
requirements that get processed before the ``egg_info`` command can be run,
the setup scripts would fail with a "Missing 'Version:' header and/or
PKG-INFO file" error, because the egg runtime interpreted the unbuilt
metadata in a directory on ``sys.path`` (i.e. the current directory) as
being a corrupted egg.  Setuptools now monkeypatches the distribution
metadata cache to pretend that the egg has valid version information, until
it has a chance to make it actually be so (via the ``egg_info`` command).

--HG--
branch : setuptools
extra : convert_revision : svn%3A6015fed2-1504-0410-9fe1-9d1591cc4771/sandbox/trunk/setuptools%4041401