Home-manager external modules from flakes

[diogox]

I was wondering if there is a way to allow adding home-manager modules like we add other external modules in the flake.nix file.

The use case I'm trying to solve is adding nix-doom-emacs's module to my user.

The workaround I currently have in place is to define:

externModules = [
  home.nixosModules.home-manager
  {
  # The workaround:
    home-manager.users.diogox = { pkgs, ... }: {
      imports = [ nix-doom-emacs.hmModule ];
    };
  }
];

Where I import the HM module for my user.

But this defines my username in the flake.nix file, which is not ideal.

Can you see any way to, I guess, either provide a mechanism that will import the HM modules for all users, or provide inputs to the user nix files, so that they can be imported there, like in the example above?

[nrdxp]

you could try using builtins.getFlake inside your user profile as a better workaround. We could probably solve this by adding another specialArg to all modules.

[diogox]

I followed your builtins.getFlake advice. It's a better workaround.

Only downside is that I need to specify the commit hash I want to fetch (as far as I can tell).

Which makes it harder to update. But it's not a big deal.

Thanks 🙌

[Pacman99]

I was just looking at the core branch and thought about this, it would be good if extern has a specialArgs attribute. It would also be useful for mobile-nixos usage, which will be getting flakes support soon.

[nrdxp]

Just inherit the modules into the empty attribute set...

[figgyc]

Hi, is there a good example on the proper usage? I'm trying to import nix-doom-emacs as described in the docs but I'm having some issues.

extern/default.nix:

{ inputs }: with inputs;
let
  hmModules = {
    inherit (nix-doom-emacs.hmModule) hmModule; # I've tried without .hmModule to the same effect
  };
in
{
  modules = [
    home.nixosModules.home-manager
    ci-agent.nixosModules.agent-profile
  ];

  overlays = [
    nur.overlay
    devshell.overlay
    emacs.overlay
    (final: prev: {
      deploy-rs = deploy.packages.${prev.system}.deploy-rs;
    })
  ];

  # passed to all nixos modules
  specialArgs = {
    inherit hmModules; # sidenote - I think this needs changing as it's "hm-modules" still in the current core branch
    overrideModulesPath = "${override}/nixos/modules";
    hardware = nixos-hardware.nixosModules;
  };
}

users/profiles/emacs/default.nix:

{ config, lib, pkgs, hmModules, ... }:

{
  imports = [ hmModules.hmModule ];
  programs.doom-emacs = {
    enable = true;
    package = pkgs.emacsPgtkGcc;
    doomPrivateDir = ./doom.d;
  };

  services.emacs = {
    enable = true;
    #package = programs.doom-emacs.package;
  };

}

The error I get:

$ flk home e7240 figgyc switch --show-trace
error: --- EvalError ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- nix
at: (303:28) in file: /nix/store/pz44872rmpd7ygqfmdcwh4ac6hk1hy4s-source/lib/modules.nix

   302|         value = builtins.addErrorContext (context name)
   303|           (args.${name} or config._module.args.${name});
      |                            ^
   304|       }) requiredArgs);

infinite recursion encountered
(use '--show-trace' to show detailed location information)

[Pacman99]

for one thing, specialArgs only affects the nixos configurations and not home-manager. So you would have to do the import in your user profile:

{ hm-modules, ... }:
{ home-manager.users.me.imports = hm-modules; }

Then you can use the modulle in any user profile.

But I have no idea how you got an infinite recursion error, I would have thought the error would be from the file not being called with hmModule.

[nrdxp]

I fixed the typo in lastest core, also put a bit of documentation up last night, I'll expand with this example later. But for now, get it working. Also made it available by default from the community branch.

[figgyc]

Yeah that works perfectly. Thanks!