treewide: rename fetchPypi -> fetchFromPyPI

[Synthetica9]

Motivation for this change

This rename does two things:

1. Brings the capitization in line with the preferred capitization:
   PyPI is short for "Python Package Index" and references itself with
   this capitalized name.
2. Adds "From". This is for consistency with other fetchers, which use
   from when fetching from a central or default repository:
   • fetchFromGitHub
   • fetchFromGitLab
   • fetchFromSourcehut
   • etc.
     A fetcher without "From" is used for fetchers without a central or
     default repository:
   • fetchurl
   • fetchpatch
   • fetchgit
   • fetchzip
   • etc.
     Since PyPI has a central repository, it should use the first pattern.

NB. This is intended to be a 0-rebuild change, so while it affects a large amount of files it should not cause a mass rebuild.

TODO:

• Update release note
• Add alias with warning for old fetchPypi

Things done

• Tested using sandboxing (nix.useSandbox on NixOS, or option sandbox in nix.conf on non-NixOS linux)
• Built on platform(s)
  • NixOS
  • macOS
  • other Linux distributions
• Tested via one or more NixOS test(s) if existing and applicable for the change (look inside nixos/tests)
• Tested compilation of all pkgs that depend on this change using nix-shell -p nixpkgs-review --run "nixpkgs-review wip"
• Tested execution of all binary files (usually in ./result/bin/)
• Determined the impact on package closure size (by running nix path-info -S before and after)
• Ensured that relevant documentation is up to date
• Fits CONTRIBUTING.md.

[stale]

I marked this as stale due to inactivity. → More info

[AndersonTorres]

Can we redo this in a sprintable?

[Synthetica9]

I don't know how sprintable this is; it should just be merged in one shot I think and it's a fairly simple find-and-replace

[AndersonTorres]

I am thinking in something like this:

• Change the definition of fetchPypi to fetchFromPyPI
• Create the alias - outside aliases.nix, because it is filtered out when enableAliases is disabled
• Modify docs reflecting the new function
• pull-request

After this PR be merged, the sprint can begin!

The sprint can be made in small steps, after all ripgrep returns 6400+ hits

After the sprint, move the alias to aliases.nix

[FRidh]

If we're going to make a change I think it is preferable to have it instead generate an url that needs to explicitly be used with a fetcher (fetchurl), the reason being this function does not actually implement a fetcher, only a routine for computing an url.

[AndersonTorres]

If we're going to make a change I think it is preferable to have it instead generate an url that needs to explicitly be used with a fetcher (fetchurl), the reason being this function does not actually implement a fetcher, only a routine for computing an url.

You are suggesting something like this below?

src = fetchurl {
   url = pypiurl pname version;
   hash = "...";
}

I think it is not a useful distinction.

• First, because for the end user, the only thing he thinks is "well, I have seen a new Python package on PyPI; so I will use fetchFromPyPI". The user do not need to know the inner functioning of fetchFromPyPI.
• Second, because, well, under the hood, fetchFrom... uses the lower level fetchgit, fetchsvn,... fetchers.