Hi Liam,

                Sorry for the trouble. The cause is rooted in the latest updates to Setuptools and Distribute on PyPI which were launched today.

                I believe what’s happening here is pip is installing Distribute 0.7, which triggers the uninstallation of Distribute, but Distribute 0.7 (a compatibility wrapper) depends on a setuptools module to be in place to install.

                I’m unsure about the failed rollback. That looks like a separate issue in pip.

the simplest answer IMO is to not use pip to upgrade distribute/setuptools right now.

It was only working in python2 before now anyway. (https://github.com/pypa/pip/issues/650)

pip is fundamentally dependent on setuptools to perform upgrades.

the best fix I think is to move faster on making pip "PEP439 compliant"

- i.e. have pip be able to at least install from wheels w/o needing setuptools, which would remove the bootstrap headache

- see https://github.com/pypa/pip/issues/863

- this could likely involve pip replacing it's use of pkg_resources with distlib (https://github.com/pypa/pip/pull/909)

Marcus