extra-libraries: m fails due to missing system dependency

[ramirez7]

hgeometry-combinatorial has extra-libraries: m in its cabal file because it has a dependency on libm.

haskell.nix fails when trying to use hgeometry with:

error: The Nixpkgs package set does not contain the package: m (system dependency).

I believe libm is always implicitly present - it has no specific package in nixpkgs.

To work around this, I set m in my pkgs to be a no-op derivation with this overlay:

self: super:

{
  m = self.stdenv.mkDerivation {
    name = "m";
    unpackPhase = "true";
    installPhase = "mkdir -p $out";
  };
}

and that got things working fine.

Is there a better way to handle this? Or should I send this no-op derivation upstream to haskell.nix?

[ramirez7]

Update re:x-compiling and libm:

When x-compiling to Windows (mingwW64), remote-iserv failed due to issues open files/creating directories with libm. I was able to get hgeometry x-compiling by tweaking my overlay to create lib and bin dirs:

self: super:

{
  m = self.stdenv.mkDerivation {
    name = "m";
    unpackPhase = "true";
    # We have to create lib and bin to make it "look like"
    # a library
    installPhase = ''
    mkdir -p $out/lib
    mkdir -p $out/bin
    '';
  };
}

[peterbecich]

I see this here, as well: google/codeworld#1523
on commit: https://github.com/peterbecich/codeworld/tree/b0febbd6325ec4f5d68bcd6cd22cf036ecc7abe9

% nix build -f default.nix
trace: No index state specified for haskell-project, using the latest index state that we know about (2021-10-31T00:00:00Z)!
...
error: The Nixpkgs package set does not contain the package: m (system dependency).
       You may need to augment the system package mapping in haskell.nix so that it can be found.

This project also uses hgeometry:
https://github.com/peterbecich/codeworld/blob/b0febbd6325ec4f5d68bcd6cd22cf036ecc7abe9/codeworld-available-pkgs/codeworld-available-pkgs.cabal#L466

[ramirez7]

Minimal reproduction: https://gitlab.com/ramirez7/bug-repros/-/tree/864172f0637cc58b82217525f62037c73d302a9d/haskell.nix/2022/05/libm-1128