graphql-engine/nix/overlays/ghc.nix

self: super:
let
  versions = import ../versions.nix { pkgs = super; };

  ghcName = "ghc${builtins.replaceStrings ["."] [""] versions.ghcVersion}";
  ghcPatches =
    if super.stdenv.targetPlatform.isDarwin
    then [
      # Copied from https://github.com/NixOS/nixpkgs/pull/149942
      # If the GHC version is updated, we must update the patch too.
      # ---
      # Reverts the linking behavior of GHC to not resolve `-libc++` to `c++`.
      # Without this, we get the following error on macOS:
      #    ghc: loadArchive: Neither an archive, nor a fat archive: `/path/to/clang++'
      ./ghc-9.4-macOS-loadArchive-fix.patch
    ] else [ ];
in
{
  haskell = super.haskell // {
    compiler = super.haskell.compiler // {
      ${ghcName} = (versions.ensureVersion super.haskell.compiler.${ghcName}).overrideAttrs (oldAttrs: {
        patches = (if oldAttrs ? patches then oldAttrs.patches else [ ]) ++ ghcPatches;
      });
    };

    packages = super.haskell.packages // {
      ${ghcName} = super.haskell.packages.${ghcName}.override {
        overrides = hself: hsuper: {
          # ghcid tests are broken on GHC 9.4
          ghcid = super.haskell.lib.dontCheck hsuper.ghcid;
        };
      };
    };
  };

  inherit (versions) ghcVersion;
  inherit ghcName;
}