mkDerivation attribute not honored by build script?

lopter · January 3, 2023, 10:02am

Hello,

I am trying to cross-compile some package in my nix flake via an overlay, here is the derivation:

lopter/multilab/blob/c1a848c50b9774eddc083e6b46405edc77931d94/third_party/libmonome.nix

{ fetchFromGitHub, lib, liblo, python3, stdenv, wafHook }:
let
  mkLibMonome = { pname, version, src, meta }:
    stdenv.mkDerivation {
      inherit pname version src meta;

      nativeBuildInputs = [
        wafHook
        python3
      ];

      buildInputs = [
        liblo
      ];

      patches = [
        # Do not execute the program compiled to check if udev or liblo
        # were present, since it does not work when cross-compiling.
        ./libmonome_wscript_check_cc_execute_false.patch
      ];

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It is used in this output in my flake:

github.com

lopter/multilab/blob/c1a848c50b9774eddc083e6b46405edc77931d94/library/python/monolight/flake-module.nix#L72

    
      
          packages.monolight_docker_rpi = mkRPiDockerImage {
            name = "docker-registry.kalessin.fr/nix/armv6l/monolight";
            contents = [ monolightRPi ];
            config = {
              User = "${monolightUID}:${monolightUID}";
              Cmd = [ "/bin/monolight" "--lightsd-url" lightsdURL ];
            };
          };
          packages.serialosc_docker_rpi = mkRPiDockerImage {
            name = "docker-registry.kalessin.fr/nix/armv6l/serialosc";
            contents = [ pkgs.pkgsCross.raspberryPi.serialosc ];
            config = {
              User = "${serialoscUID}:${serialoscUID}";
              Cmd = [ "/bin/serialoscd" ];
            };
          };
          packages.lightsd_docker_rpi = mkRPiDockerImage {
            name = "docker-registry.kalessin.fr/nix/armv6l/lightsd";
            contents = [ pkgs.pkgsCross.raspberryPi.lightsd ];
            config = {
              User = "${lightsdUID}:${lightsdUID}";

And the build fails with:

% nix build '.#serialosc_docker_rpi'
error: builder for '/nix/store/drsqbhnwaiqrf9vdgg1939phplbikdbd-serialosc-armv6l-unknown-linux-gnueabihf-1.4.3.drv' failed with exit code 2;
       last 10 log lines:
       >     --enable-system-libuv
       >                         use libuv
       >                         provided by
       >                         the system
       >                         instead of
       >                         the
       >                         included
       >                         git
       >                         submodule.
       > waf: error: no such option: --cross-compile
       For full logs, run 'nix log /nix/store/drsqbhnwaiqrf9vdgg1939phplbikdbd-serialosc-armv6l-unknown-linux-gnueabihf-1.4.3.drv'.
error: 1 dependencies of derivation '/nix/store/d276c73zcz3m1zrwbv6vj64yl2pn5gh2-serialosc-customisation-layer.drv' failed to build
error: 1 dependencies of derivation '/nix/store/rpniidmi0rjrl1820lrk8d6z27d4ks7y-serialosc-conf.json.drv' failed to build
error: 1 dependencies of derivation '/nix/store/0a74r99igrw7xpbcsf0wxc8f9p8wmcva-stream-serialosc.drv' failed to build
error: 1 dependencies of derivation '/nix/store/9mlbd3946kb3n1ld9hy7yydh3q6gnk8p-serialosc.tar.gz.drv' failed to build
%

And I fail to understand how dontAddWafCrossFlags is not expanded in wafHook.

I failed to reproduce the issue both from a vanilla flake and using flake-parts, using both nixpkgs-22.11 and my nixpkgs fork from last year that has some Python-related cross-compilation fixes (see previous discussion).

My attempt to reproduce this issue is in GitHub - lopter/badwaf: Support code to try to reproduce some nix build issue. It has two branches, one using vanilla flake and one using flake-parts.

What is going on? How does one go about debugging it?

raphi · January 3, 2023, 2:58pm

The error is caused by the serialosc derivation, not the libmonome derivation. There is no dontAddWafCrossFlags in serialosc.nix.

lopter · January 3, 2023, 9:14pm

Omg, thank you, I totally missed that T_T.