flake: remove the 'follows' directive

[teto]

nixFlake suffers from a bug when using "follows" keyword:
NixOS/nix#3602

I think the (possibly) extra-downloads is worth having the peace of mind that it always works.

[berberman]

We have to make sure that formatters in pre-commit hooks are consistent (#1408), so I think the follow of nixpkgs is required. For flake-utils, I agree with removing that follow.

[teto]

the "follow" is broken in nix which means I can't use the flake without a fork.

Alternatively, could we :

• fork pre-commit-hook so that we can manually make sure they use the same nixpkgs version as hls ?
• override stylish-haskell in the pre-commit flake with the one from hls' overlay ?

[berberman]

fork pre-commit-hook so that we can manually make sure they use the same nixpkgs version as hls

I don't think that's a good idea, since it causes extra maintenance

override stylish-haskell in the pre-commit flake with the one from hls' overlay

Actually we already do this:

haskell-language-server/flake.nix

Line 137 in 48221c7

stylish-haskell.entry = pkgs.lib.mkForce "${hpkgs.stylish-haskell}/bin/stylish-haskell --inplace";

So maybe we don't need "follow" nixpkgs at all, and this PR may work. Could you try executing the pre-commit hook?

[teto]

stylish-haskell --version gives me stylish-haskell 0.12.2.0.
If I trigger the hook. It works correctly but not sure how to check it uses the same version.

[berberman]

Thanks for confirming, then we are good to go