Marking conda as installer for pip packages

All of the python package recipes which have python -m pip install ... or just pip install ... create one problem. They install a file by the name ‘INSTALLER’ in the dist-info directory. For example:

$ cat /Users/nwani/m3/envs/test/lib/python3.7/site-packages/dbf-0.97.11.dist-info/INSTALLER
pip

This is bad, because the from a user’s perspective, when an end user does: conda install dbf this package is installed via ‘conda’ and not ‘pip’. The upcoming release of pip will have a new function was_installed_by_pip(): This is going to be used for not telling the user to pip install --upgrade pip if pip is not installed via pip. I was thinking of extending it to all packages not installed by pip pypa/pip#5605 .

So, what would you recommend, conda-forge? Should we:

• stop using pip install and use the old --single-version-externally-managed
• start doing echo conda > /path/to/pkg-pkgversion.dist-info/INSTALLER
• add a patch to pip which adds an argument to mark the installer
• delete the INSTALLER file?

[ChrisBarker-NOAA]

This is tricky, as people use conda and pip together. So when someone “pip installs” something, we DO want pip to think that any already-there dependencies were installed by pip (or, I guess, just that they are installed). Which is why we’ve been installing stuff with pip in conda-build.

also – the theory is that pip might install packages that are built with tools other than setuptools – so we can have one front end to all python package builders/installers.

So if pip does grow a way to indicate whether a package is being managed by pip, it would be really nice if it could still install a package, but optionally say “don’t try to manage this one”. SO maybe a PR to pip is in order. (or a post-install hack)

Of course making sure pip knows it is not managing itself is a good idea – that could get ugly.

and I do like @jakirkham’s idea of a generic python “compiler” that could be managed in one place as these things change – could we add a {{ installer("python") }} instead?

-CHB

[jjhelmus]

I would be in favor of recording conda or something similar in the INSTALLER file.