nixos integration: add option 'useGlobalPkgs'

PR #1059

2 files changed, 27 insertions, 6 deletions

diff --git a/modules/misc/news.nix b/modules/misc/news.nix
index 0f0c2ac1674..cc2892e87b7 100644
--- a/modules/misc/news.nix
+++ b/modules/misc/news.nix
@@ -1351,6 +1351,21 @@ in
           '--description', '--on-event', and more.
         '';
       }
+
+      {
+        time = "2020-03-07T13:11:43+00:00";
+        condition = hostPlatform.isLinux;
+        message = ''
+          The NixOS module has a new option: 'home-manager.useGlobalPkgs'.
+
+          This enables using the system configuration's 'pkgs'
+          argument in Home Manager.
+
+          To learn more, see the installation section of the manual
+
+            https://rycee.gitlab.io/home-manager/#sec-install-nixos-module
+        '';
+      }
     ];
   };
 }
diff --git a/modules/modules.nix b/modules/modules.nix
index 9d741016fbe..263c1176cc6 100644
--- a/modules/modules.nix
+++ b/modules/modules.nix
@@ -5,6 +5,9 @@
 
   # Whether to enable module type checking.
 , check ? true
+
+# If disabled, the pkgs attribute passed to this function is used instead.
+, useNixpkgsModule ? true
 }:
 
 with lib;
@@ -27,7 +30,7 @@ let
     (loadModule ./misc/gtk.nix { })
     (loadModule ./misc/lib.nix { })
     (loadModule ./misc/news.nix { })
-    (loadModule ./misc/nixpkgs.nix { })
+    (loadModule ./misc/nixpkgs.nix { condition = useNixpkgsModule; })
     (loadModule ./misc/numlock.nix { condition = hostPlatform.isLinux; })
     (loadModule ./misc/pam.nix { })
     (loadModule ./misc/qt.nix { })
@@ -170,11 +173,14 @@ let
   modules = map (getAttr "file") (filter (getAttr "condition") allModules);
 
   pkgsModule = {
-    config._module.args.baseModules = modules;
-    config._module.args.pkgs = lib.mkDefault pkgs;
-    config._module.check = check;
-    config.lib = lib.hm;
-    config.nixpkgs.system = mkDefault pkgs.system;
+    config = {
+      _module.args.baseModules = modules;
+      _module.args.pkgs = lib.mkDefault pkgs;
+      _module.check = check;
+      lib = lib.hm;
+    } // optionalAttrs useNixpkgsModule {
+      nixpkgs.system = mkDefault pkgs.system;
+    };
   };
 
 in