home-manager: set module class to "homeManager"

roberth · rycee · commit 26e72d85e6fb · 2024-04-27T09:28:21.000+02:00
This enables a module system feature documented here: https://nixos.org/manual/nixpkgs/stable/index.html#module-system-lib-evalModules-param-class For example, it allows a mistake to be caught, which is loading a NixOS module into home-manager. This only works when the offending module declares what it's for with a `_class` attribute. It is not expected that users declare the `_type`, because the payoff is small. It is only expected to be set by generic code, such as functions or libraries that help with the "publishing" of modules (e.g. flake-parts, flake-utils). The class feature has been available in the module system since NixOS/nixpkgs#197547, merged May 6, 2023. It has been part of all releases since 23.05-beta. The last NixOS release that did _not_ support it has been end-of-life for close to a year now. Example: (lib.homeManagerConfiguration { pkgs = nixpkgs.legacyPackages.x86_64-linux; modules = [{ _class = "nixos"; imports = [ ./foo.nix ]; }]; }).activation-script Corresponding error: error: The module <unknown-file> was imported into homeManager instead of nixos. (`<unknown-file>` can be improved by also setting `_file`, if known; a much older feature) PR #5339
diff --git a/docs/default.nix b/docs/default.nix
@@ -55,7 +55,11 @@ let
   hmPath = toString ./..;
 
   buildOptionsDocs = args@{ modules, includeModuleSystemOptions ? true, ... }:
-    let options = (lib.evalModules { inherit modules; }).options;
+    let
+      options = (lib.evalModules {
+        inherit modules;
+        class = "homeManager";
+      }).options;
     in pkgs.buildPackages.nixosOptionsDoc ({
       options = if includeModuleSystemOptions then
         options
@@ -160,6 +164,7 @@ in {
         inherit lib pkgs;
         check = false;
       } ++ [ scrubbedPkgsModule ];
+      class = "homeManager";
     };
   in builtins.toJSON result.config.meta.maintainers);
 }
diff --git a/modules/default.nix b/modules/default.nix
@@ -25,6 +25,7 @@ let
 
   rawModule = extendedLib.evalModules {
     modules = [ configuration ] ++ hmModules;
+    class = "homeManager";
     specialArgs = { modulesPath = builtins.toString ./.; } // extraSpecialArgs;
   };
 
diff --git a/nixos/common.nix b/nixos/common.nix
@@ -13,6 +13,7 @@ let
 
   hmModule = types.submoduleWith {
     description = "Home Manager module";
+    class = "homeManager";
     specialArgs = {
       lib = extendedLib;
       osConfig = config;
