"UserWarning: Unbuilt egg for setuptools" - What does this actually mean?

Question

When I install things into a virtualenv using pip I often see the message "UserWarning: Unbuilt egg for setuptools". I always safely ignore it and go about my business and it doesn't seem to cause me any problems.

But I've suddenly been smacked in the face with curiosity, and wondered if someone could explain what it means, exactly?

Also, does the new virtualenv option to use distribute instead fit into all this somewhere? Should I be using that instead, or just ignoring it until distutils2 comes out? (apologies if that's totally unrelated - maybe it should be a new question?)

Thanks!

Answer 1

The answer and workaround in this Ubuntu bug report fixed this issue for me, where I was reading the same error while using interactive trac-admin command.

Marius Gedminas, said:

Workaround:

sudo rmdir /usr/lib/python2.6/dist-packages/setuptools.egg-info

sudo apt-get install --reinstall python-setuptools

This replaces the empty directory /usr/lib/python2.6/dist-packages/setuptools.egg-info with a symlink to /usr/share/pyshared/setuptools.egg-info which is a file, not a directory.