@erictapen Could you remove hakyll from the list of known broken packages?

See this explanation on how to to this:

https://discourse.nixos.org/t/video-tutorial-how-to-fix-broken-haskell-packages-in-nix/3968

I've confirmed that hakyll builds, so once you do this we can get this PR merged in.

Ah right, forgot about that one. I removed the entry!

i have a somewhat tangential question about this PR, feel free to ignore. if i'm on the nixpkgs-19.09-darwin channel, which doesn't appear to have this commit yet, how might i override my hakyll in my config.nix to adopt the changes here, to fix my hakyll build?

@mjhoy

Here's a script that you can use with nix-build to apply the fix from this PR and build hakyll. Although this didn't build on my 19.09 system, so you may need to bump the version of hakyll as well:

with (import <nixpkgs> {});

let
  haskellPackagesWithHakyll =
    haskellPackages.override {
      overrides = hself: hsuper: {
        hakyll =
          haskell.lib.markUnbroken
            ( if stdenv.isDarwin
              then
                haskell.lib.dontCheck (haskell.lib.overrideCabal hsuper.hakyll (drv: {
                  testToolDepends = [];
                }))
              else hsuper.hakyll
            );
      };
    };
in

haskellPackagesWithHakyll.hakyll

Although you'll have to adapt this slightly for use in config.nix. You can find out how to do that in the nixpkgs manual (or maybe it was the nix manual?). The haskell section in the nixpkgs manual also describes multiple ways of overriding Haskell packages. You might find that interesting.

@mjhoy The way I do it is to not use the channel but:

• clone the git repository nixpkgs-channels
• checkout the branch nixpkgs-19.09-darwin
• create your own custom branch, e.g. custom-19.09
• git cherry-pick the commits you need ontop of it

If you want to update, you can rebase the branch ontop of nixpkgs-19.09-darwin

That way you have one easy way to use arbitrary edits to Nixpkgs, that haven't made it into master or the channels yet.

@cdepillabout thanks! i did not know about haskell.lib.markUnbroken which gets me part of the way there. i still have trouble because it seems i actually need to remove the appended patch, as i run into this error:

hash 'sha256-F59WHt52LOKGsGoaD3LAIZFEMe9s9WHfGxQgSh9Q8uQ=' has wrong length for hash type 'sha256'

@erictapen cool, for whatever reason i couldn't find this commit, maybe commits from haskell-updates get squashed periodically or something? but applying the patch from this PR, and also marking unbroken with hakyll = haskell.lib.markUnbroken super.hakyll in my haskellOverrides worked (otherwise it still was marked as broken and refused to evaluate).