[miso] attribute extend missing error when using custom GHC package set

[newton-migosi]

I've defined a custom GHC package set based off of miso's package set defined here https://github.com/dmjio/miso/blob/843bdc3d39f7387f5306e451bab8a2dbfa11fca0/nix/overlay.nix#L20-L39

This seems to trigger an error that points to the usage of extend in haskell-flake here

haskell-flake/nix/modules/project/outputs.nix

Line 91 in 7029034

finalPackages = config.basePackages.extend finalOverlay;

Are there any known configurations of package sets that would throw such errors?

[newton-migosi]

The author of NixOS/nixpkgs#38522 was 99% sure extend wouldn't break anything

But I'm 99% sure this can't break anything and is fully backwards compatible.

[srid]

Since extend is used outside of haskell-flake, this shouldn't be haskell-flake specific.

What is the error? You can also try posting here

[newton-migosi]

Getting the same error for both

nix-repl> debug.allSystems.x86_64-linux.haskellProjects.default.basePackages.aeson
error: attribute 'extend' missing

       at /nix/store/k066hn412qjzs933n8dk8xqsnpqhj1sb-source/nix/modules/project/outputs.nix:91:23:

           90|
           91|       finalPackages = config.basePackages.extend finalOverlay;
             |                       ^
           92|

nix-repl> debug.allSystems.x86_64-linux.haskellProjects.default.basePackages      
error: attribute 'extend' missing

       at /nix/store/k066hn412qjzs933n8dk8xqsnpqhj1sb-source/nix/modules/project/outputs.nix:91:23:

           90|
           91|       finalPackages = config.basePackages.extend finalOverlay;
             |                       ^
           92|

[srid]

Looks like you are setting basePackages of this flake to the finalPackages of some another flake (via project modules?). If so, you want to debug repl on that flake.

Aside: we should probably add some type checking to the types.raw here:

haskell-flake/nix/modules/project/default.nix

Lines 64 to 65 in 7029034

	basePackages = mkOption {
	type = types.attrsOf raw;

[newton-migosi]

yes, I have an output that I'm using as a base package

nix-repl> debug.allSystems.x86_64-linux.haskellProjects.ghc865.outputs.
debug.allSystems.x86_64-linux.haskellProjects.ghc865.outputs.apps
debug.allSystems.x86_64-linux.haskellProjects.ghc865.outputs.checks
debug.allSystems.x86_64-linux.haskellProjects.ghc865.outputs.devShell
debug.allSystems.x86_64-linux.haskellProjects.ghc865.outputs.finalOverlay
debug.allSystems.x86_64-linux.haskellProjects.ghc865.outputs.finalPackages
debug.allSystems.x86_64-linux.haskellProjects.ghc865.outputs.packages

nix-repl> debug.allSystems.x86_64-linux.haskellProjects.ghc865.outputs.finalPackages
error: attribute 'extend' missing

       at /nix/store/k066hn412qjzs933n8dk8xqsnpqhj1sb-source/nix/modules/project/outputs.nix:91:23:

           90|
           91|       finalPackages = config.basePackages.extend finalOverlay;
             |                       ^
           92|

nix-repl> debug.allSystems.x86_64-linux.haskellProjects.ghc865.outputs.packages     
{ }

Here is my nix flake file and the definition of my package set: https://gist.github.com/newton-migosi/74d1c9f0ab3b343e20d40f46880a92fa

[srid]

Ah, you are setting basePackages of that ghc865 flake to something other a Haskell package set, which is not supported of course.

https://gist.github.com/newton-migosi/74d1c9f0ab3b343e20d40f46880a92fa#file-ghc865-nix-L3-L10

# In effect
basePackages = (import inputs.miso { system = inputs.system; allowBroken = true; }).miso-ghc

This does not necessarily conform to the type interface of pkgs.haskellPackages, in fact it seems to be a single package (see https://github.com/dmjio/miso/blob/843bdc3d39f7387f5306e451bab8a2dbfa11fca0/default.nix#L56) ... hence, cannot be used as is with haskell-flake.

[srid]

You just want basePackage = pkgs.haskell.packages.ghc865; more likely.

[newton-migosi]

Maybe I can copy over their haskell overrides manually? They seem to be making minor overrides

haskell = super.haskell // {
    packages = super.haskell.packages // {
      ghc865 = super.haskell.packages.ghc865.override {
        overrides = import ./haskell/packages/ghc865 self;
      };
      ghc864 = super.haskell.packages.ghc864.override {
        overrides = selfGhc864: superGhc864: with super.haskell.lib; {
          happy = dontCheck (selfGhc864.callHackage "happy" "1.19.9" {});
          mkDerivation = args: superGhc864.mkDerivation (args // {
            enableLibraryProfiling = false;
            doCheck = false;
            doHaddock = false;
          });
        };
      };
      ghcjs86 = super.haskell.packages.ghcjs86.override {
        overrides = import ./haskell/packages/ghcjs options self;
      };
    };
  };

[srid]

You can apply their overlay.nix to your flake, see _module.args.pkgs in flake-parts.

https://flake.parts/overlays.html?highlight=overlays#consuming-an-overlay

[newton-migosi]

nix-repl> :t debug.allSystems.x86_64-linux.haskellProjects.ghc865.basePackages 
a set

nix-repl> debug.allSystems.x86_64-linux.haskellProjects.ghc865.basePackages
«derivation /nix/store/8hwfxms0z5i7kjpamsvw97jym6rh6bsy-miso-1.8.3.0.drv»