Specify name in cleanSourceWith

[bouk]

If you don't specify the name then the src name is used, which will be based on the unfiltered source tree. This means that the output still depends on the input files that are filtered out, and extra builds are done that aren't needed.

I figured this out by debugging why changing any file in my git repo flake caused everything to be rebuilt again, which happens because the src name changes every time anything is changed at all.

Ref: https://nixos.org/manual/nix/stable/language/builtins.html#builtins-filterSource

[bouk]

Looking at the implementation of toSourceAttributes I'm not entirely sure now... I might just be running into https://github.com/NixOS/nix/issues/5870

[Fuuzetsu]

225 works around it I think.