@zimbatm, thanks for your PR! By analyzing the history of the files in this pull request, we identified @krgn, @wkennington and @peterhoeg to be potential reviewers.

👍

i imagine there are many other situations where fetchmulti could be used. is there a way to grep for those cases?

also do we need to document this? are other fetch* functions documented?

The name fetchmulti implies that it fetches multiple files. But if I understand it correctly, it fetches just one file from a selection. So it should be something like fetchOneOf.

Thanks for the reviews! I realize my vision isn't complete here and it's more of a 20% review.

The problem I am trying to solve is that it takes a lot of time to update packages. Most of the time it's enough to bump the version and update the sha256 but right now it's hard to automate that because the data is mixed with the mkDerivation bits. First bump the version, then run nix-prefetch-url and copy-and-paste the sha256 back into the file. My thinking is that if that data would be externalized then it would make things easier to automate.

Right now all I am doing in this PR is to move all the data into a pure nix (NIXON) declaration (which explain why fetcher is also a string) with the idea that in a further PRs I will be able to move that out to a separate file. I also converted a couple of files to fetchOneOf to demonstrate how it would work but there are a lot left to do.

I want us to get into a situation where the source data can live in a separate file (eg: fetchdata import ./source.nix) and have a tool that's able to update that external file either automatically by finding the list of upstream releases or manually with the user giving the version that he wants. If we have that we can also notify the maintainers of new releases and get a better sense of which parts of nixpkgs need more work.

If we can agree on the fetcher as a key and that interface in general I am happy to just propose the fetchOneOf fetcher in this PR and wait for the more complete picture to form before introducing the fetchdata function into nixpkgs.

What do you think?

@garbas for now my approach to finding multi-arch binaries is to grep for x86_64.*\.tar but it's not perfect

Moving the discussion to #19582. I will come back with a more complete solution with my updating script idea.