setuptools 45.0.0 gets installed on a python 2.7 virtualenv

Hello,

I have a CI job that creates a virtualenv from an old version (relying on pip==8.1.2) with python 2.7.

I then ask pip to update setuptools wheel pip. In the process it installs setuptools==45.0.0 and updates pip==19.3.1.

The rest of the CI fails because pip refuses to install the other dependencies due to setuptools incompatibility with python 2.7.

I believe that this could be avoided by removing:

[bdist_wheel]
universal = 1

from setup.cfg.

What is the reason for keeping this option in the cfg?

[fungi]

bdist_wheel.universal=1 is still a problem though, because it results in a py2.py3 wheel, which inherently means the file is expected to work with at least some Python 2 interpreter. If this file winds up in a local wheelhouse or a remote one served with an unintelligent index rather than PyPI itself (e.g., Apache mod_autoindex) then pip on Python 2.7 will attempt to install it anyway rather than selecting an older version.

[exarkun]

@hugovk This didn’t seem to work for us. Our current workaround is to run

pip install -U pip
pip install setuptools==44.0.0

before installing the rest of our dependencies.

I also had to ask for setuptools==44.0.0 explicitly. There is already a setuptools installed in the virtualenv, by the older version of pip, and I guess pip won’t downgrade to a working version if you only do pip install -U setuptools.