My messy package.nix:

{
  lib,
  rustPlatform,
  clang,
  pkgs ? import <nixpkgs> {},
}: let
  cargoToml = builtins.fromTOML (builtins.readFile ../Cargo.toml);
in
  rustPlatform.buildRustPackage rec {
    inherit (cargoToml.package) version;
    pname = cargoToml.package.name;
    cargoLock = {
      lockFile = ../Cargo.lock;
      outputHashes = {
        "burn-0.14.0" = "sha256-5ssNI+QvMpEeU7JpK1KVtBpTgXKbaqTUYTBePTL+J24=";
        "cubecl-0.1.1" = "sha256-xgwXyHAKSxf4rTF/Svpb61IOvxQUiV9xmOXk5WHDdjY=";
      };
    };
    src = lib.cleanSource ../.;
    nativeBuildInputs = with pkgs; [
      clang
      fontconfig
      pkg-config
      libxkbcommon
      libGL
      cmake

      wayland

      xorg.libXcursor
      xorg.libXrandr
      xorg.libXi
      xorg.libX11

      vulkan-headers
      vulkan-loader
    ];
    buildInputs = with pkgs; [
      clang
      fontconfig
      pkg-config
      libxkbcommon
      libGL
      cmake

      wayland

      xorg.libXcursor
      xorg.libXrandr
      xorg.libXi
      xorg.libX11

      vulkan-headers
      vulkan-loader
    ];
    LIBCLANG_PATH = "${pkgs.libclang.lib}/lib";
    LD_LIBRARY_PATH = "${pkgs.lib.makeLibraryPath buildInputs}";
  }

In reply to @simon.brandner:envs.net
Hmm, it might be me being stupid...

Hi folks, is it not possible to directly change the sources in $src during any of the phases? Imagine I need to add a generic target to Makefile, so I wanted to do something like:

  mySource = ./extraMakeTarget.txt
  <somePhase> = ''
    cat $mySource >> $src/makefile
  '';

But I am getting a Permission Denied error.

In reply to @quapka4:matrix.org
I assumed that during the phases I kinda have a full access to whatever sources I have, because my changes through any phase end up in the resulting hash anyway.

In reply to @soispha:vhack.eu
You actually do, but the source (refered to by $src) is still in the read-only nix store. You probably want to change the upacked source, which should be in the working directory of the builder

In reply to @simon.brandner:envs.net
It could be an issue with OUT_DIR not being set correctly...

In reply to @quapka4:matrix.org
And I guess postUnpack would be the appropriate place.

In reply to @quapka4:matrix.org
Hi, a simple thing :D. I have a flake.nix that builds on my NixOS machine, but when I tried to build that flake on another non-NixOS machine that has Nix installed with nix-user-chroot the build fails on one particular package (libgpg-error). What is the reasonable way to debug this?