Recently I needed to install devenv using flakes in home-manager. One of the things I needed to pass to was the type of system to install on i.e. "x86_64-linux".

So as I temp hack I had something like: inputs.devenv.packages."x86_64-linux".devenv.

However I was able to access the system using the pkgs attribute like so:

{
  inputs,
  pkgs,
  ...
}: {
  home.packages = [
    inputs.devenv.packages."${pkgs.system}".devenv
  ];
}

Where my flake.nix looks something like:

  outputs = {
    self,
    nixpkgs,
    home-manager,
    ...
  } @ inputs: let
  in {
    inherit lib;
    homeConfigurations = {
      # Desktops
      mesmer = lib.homeManagerConfiguration {
        modules = [./hosts/mesmer/home.nix];
        pkgs = nixpkgs.legacyPackages.x86_64-linux;
        extraSpecialArgs = {inherit inputs outputs;};
      };
    };
  };

You can see here the system is defined with the pkgs, as I guess we need to know for which architecture we should build for i.e. amd, arch etc. But yeh thats it! For use within home-manager it seems we can use pkgs.system, to access the architecture, so we don’t need to hardcode it.