Importing modules without using `--impure`

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1

I am working on updating a module in nixpkgs and to test locally, I typically use the following configuration:

# flake.nix

{
  inputs = {
    nixpkgs.url = "github:NixOS/nixpkgs/...";
    nixpkgs-dq = "github:dq/nixpkgs/...";
    ...
  };

  outputs =
    inputs@{
      self,
      ...
      nixpkgs,
      nixpkgs-dq,
      ...
      ...
    }:
    let
      specialArgs = {
        inherit inputs;
        pkgs-dq = import nixpkgs-dq {
          system = "aarch64-linux";
          config.allowUnfree = true;
        };
      };
      extraSpecialArgs = { inherit inputs; };
    in
    rec {
      ...
      nixosConfigurations."dq" = nixpkgs.lib.nixosSystem {
        inherit specialArgs;
        system = "aarch64-linux";
        modules = [
          ...
          ./machines/dq/configuration.nix
          ...
        ];
      };
      ...
}

# ./machines/dq/configuration.nix
{
  ...
  pkgs,
  pkgs-dq,
  ...
}:
{
  disabledModules = [
    "services/audio/example.nix"
  ];
  imports = [
    /path/to/local/nixpkgs/nixos/modules/services/audio/example.nix
  ];

  # will now use service module and package in local nixpkgs on rebuild
  services.audio.example.enable = true;
  services.audio.example.pkg = pkgs-dq.audiopkg;
  ...
}

The only small drawback here is having to use --impure on system rebuild.

I tried different approaches:

imports = [
  pkgs-dq.services.audio.example
];

imports = [
  <pkgs-dq/services/audio/example>
];

imports = [
  "pkgs-dq/services/audio/example"
];
2 
{ inputs, pkgs, ... }:
{
  imports = [
    "${inputs.nixpkgs-dq}/nixos/modules/services/audio/example.nix"
  ];
}
1 Like
3

yes, that works. Thank you!

And this works as well (while chatting with folks on #users:nixos.org):

{
  pkgs-dq,
  ...
}:
{
  ...
  imports = [
    "${pkgs-dq.path}/nixos/modules/services/audio/example.nix
  ];
}