Initial implementation of python modules with poetry

[layus]

This has been long in the making, and currently it only works in a very
restricted setup. Nonetheless, it comes with a working example, so comments are
welcome.

[aherrmann]

Thank you for pushing this forward! This is a really cool feature, and I don't think much is missing to have this ready to merge. I've added a couple comments.

[layus]

Stuck on some disk space limitation. Probably /run/usr/${id} AFAIR, because nix uses that as $TMP and mach-nix fills it by unpacking it's database of all the python packages it knows.

[aherrmann]

This provides a solution to #346 for Python.

[layus]

Done, I think it is as ready as can be.

[aherrmann]

Thank you @layus , this is great!
I've added a few more comments, but all of them are small comments.
Please address the comments and then feel free to add the merge-queue label.

[layus]

Concerning mach-nix, it is way too difficult to make it work on recent nixpkgs, the project is currently unmaintained, and last update it received references a nixpkgs from one year ago. I remembered just in time that you can craft python packages sets manually in nixpkgs.
Once dream2nix support for python improves, we could also add it to the list. DavHau moved it's focus from mach-nix to dream2nix, so I am pretty confident dream2nix will make steady progress on python. I will never thank that person enough ✨

[layus]

@aherrmann Thanks for your thorough and fast reviews, working on this PR has been a real pleasure !

[aherrmann]

Once dream2nix support for python improves, we could also add it to the list. DavHau moved it's focus from mach-nix to dream2nix, so I am pretty confident dream2nix will make steady progress on python. I will never thank that person enough sparkles

That sounds very exciting! Yes, perhaps there is even a way to use dream2nix more broadly for rules_nixpkgs integration of different languages.

Thanks for your thorough and fast reviews, working on this PR has been a real pleasure !

Likewise, thank you for the great work!