bug: attribute 'dag' missing when trying to use activations

[jamesla]

Is there an existing issue for this?

• [X] I have searched the existing issues

Issue description

I am trying to use a home manager activation and following the docs here: https://rycee.gitlab.io/home-manager/options.html#opt-home.activation

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

with lib;

let
  home-manager = builtins.fetchTarball
    "https://github.com/nix-community/home-manager/archive/master.tar.gz";
in {
  imports = [ (import "${home-manager}/nixos") ];

  home.activation.test = lib.hm.dag.entryAfter ["writeBoundary"] ''
    echo hello world
  '';
}

I get the following error:

error: attribute 'hm' missing, at /home/vagrant/nixos/home.nix:113:28

Where can I find dag and how can I import it?

Maintainer CC

No response

System information

- system: `"x86_64-linux"`
 - host os: `Linux 5.10.106, NixOS, 21.11 (Porcupine)`
 - multi-user?: `yes`
 - sandbox: `yes`
 - version: `nix-env (Nix) 2.3.16`
 - nixpkgs: `/nix/var/nix/profiles/per-user/root/channels/nixos`

[ncfavier]

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

let
  home-manager = builtins.fetchTarball
    "https://github.com/nix-community/home-manager/archive/master.tar.gz";
in {
  imports = [ "${home-manager}/nixos" ];

  home-manager.users.you = { lib, ... }: {
    home.activation.test = lib.hm.dag.entryAfter ["writeBoundary"] ''
      echo hello world
    '';
  };
}

[eyeinsky]

This should probably be documented better in the documentation for home.activation option.

[ncfavier]

This has nothing to do with home.activation. The relevant section of the manual is https://nix-community.github.io/home-manager/index.html#sec-install-nixos-module. Maybe we could mention lib in that section.

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