Using a Nix Package or NixOS Module from a Separate Fork of Nixpkgs

This guide will show you how to use a Nix package or NixOS module from a separate fork of nixpkgs.

Step 1: Define the Forked Repository

In your Nix file, define the forked repository using fetchFromGitHub function:

nixpkgs.overlays = [
  (self: super: {
    <your-package> = (import
      (pkgs.fetchzip (
        let owner = "<owner>"; branch = "<branch>"; in {
          url = "https://github.com/${owner}/nixpkgs/archive/${branch}.tar.gz";
          # Change to 52 zeros when archive needs to be redownloaded.
          sha256 = "<sha256>";
        }
      ))
      { overlays = [ ]; config = super.config; }).<your-package>;
  })
];

In this example, replace <your-package>, <owner>, <branch>, and <sha256> with the actual values from the forked repository.

Step 2: Use Packages or Modules from the Forked Repository

Now you can use packages or modules from the forked repository in your Nix expressions. For example, if you want to use a package from the forked repository, you can refer to it using the <your-package> attribute. Here’s an example:

{
  environment.systemPackages = with pkgs; [
    <your-pckage>
  ];
}

In this example, replace <your-package with the actual name of the package you want to use.