Configure pip during build to avoid dependencies

[jakirkham]

Currently we patch setuptools to know when conda-build is running and disable pulling in dependencies. This is a good thing and avoids a fair number of issues. However am unaware of us doing anything on this front with pip, which could be problematic if users start pulling in dependencies that way by accident. As this has become a recommendation for Python packages in conda-forge ( conda-forge/conda-forge.github.io#518 ), this deserves more consideration.

One option would be to address this in conda-build, this could amount to setting a pip.conf or pip.in for pip to use based on one internally included and maintained in conda-build. Another option would be to set a number of environment variables for the active build environment to get the same effect. In either case this should allow us to block downloads, avoid build isolation, disable caching, and any other behavior that might be confusing or problematic for end users building conda packages with pip.

[msarahan]

Conda-build is already setting env vars for when you're in a build. We'd need to patch pip to find and act on those env vars, but I really don't think this is a conda-build issue. Instead, it is one for pip-feedstock.

[jakirkham]

We could patch the pip feedstock. It would probably need to be an activation script.

[jakirkham]

Alternatively we could have a post-link script that writes to the pip.conf/pip.ini in whatever standard location we decide it should live in only if conda-build is running. ( pypa/pip#5060 )

[msarahan]

Why does it have to be a pip.conf file? I mean, we can certainly do that, if it's the easiest way. If that's what we do, then doing it in conda-build is going to be much nicer than doing it in a post-link or activate script.

If we have to hack pip at all to make it work, why not patch it like setuptools?

[jakirkham]

We could also teach pip where to look for this config file ( pypa/pip#5060 ), which could easily be sent upstream.

[jakirkham]

Solved in PR ( #2972 ), which is included in conda-build version 3.11.0+.

[jakirkham]

Noticed there were a couple things missing. Added PR ( #3053 ) to set them as well.

[github-actions]

Hi there, thank you for your contribution!

This issue has been automatically locked because it has not had recent activity after being closed.

Please open a new issue if needed.

Thanks!