feat: Context for host with home-manager users.

modules/aspects/dependencies.nix

@@ -6,15 +6,11 @@ let
   inherit (den.lib)
     owned
     statics
-    parametric
+    take
     ;
 
-  inherit (den.lib.take) exactly;
-
   dependencies = [
-    (exactly osDependencies)
-    (exactly hmUserDependencies)
-    (exactly hmStandaloneDependencies)
+    (take.exactly osDependencies)
   ];
 
   osDependencies =
@@ -50,45 +46,6 @@ let
       ];
     };
 
-  # from OS home-managed integration.
-  hmUserDependencies =
-    {
-      OS-HM,
-      host,
-      user,
-    }:
-    let
-      inherit (OS-HM) OS HM;
-      context = {
-        inherit
-          OS
-          HM
-          user
-          host
-          ;
-      };
-    in
-    {
-      includes = [
-        (owned den.default)
-        (statics den.default)
-        (owned HM)
-        (statics HM)
-        (parametric.fixedTo context OS)
-      ];
-    };
-
-  hmStandaloneDependencies =
-    { HM, home }:
-    den.lib.take.unused home {
-      includes = [
-        (owned den.default)
-        (statics den.default)
-        (owned HM)
-        (statics HM)
-      ];
-    };
-
 in
 {
   den.default.includes = dependencies;

modules/aspects/provides/home-manager/hm-dependencies.nix

@@ -0,0 +1,45 @@
+{
+  den,
+  ...
+}:
+let
+  inherit (den.lib)
+    owned
+    statics
+    parametric
+    take
+    ;
+
+  dependencies = [
+    (take.exactly hmUserDependencies)
+    (take.exactly hmStandaloneDependencies)
+  ];
+
+  # from OS home-managed integration.
+  hmUserDependencies =
+    { HM-OS-USER }:
+    {
+      includes = [
+        (owned den.default)
+        (statics den.default)
+        (owned HM-OS-USER.HM)
+        (statics HM-OS-USER.HM)
+        (parametric.fixedTo HM-OS-USER HM-OS-USER.OS)
+      ];
+    };
+
+  hmStandaloneDependencies =
+    { HM, home }:
+    take.unused home {
+      includes = [
+        (owned den.default)
+        (statics den.default)
+        (owned HM)
+        (statics HM)
+      ];
+    };
+
+in
+{
+  den.default.includes = dependencies;
+}

modules/aspects/provides/home-manager.nix → modules/aspects/provides/home-manager/hm-integration.nix

@@ -26,25 +26,28 @@ let
   '';
 
   homeManager =
-    { OS, host }:
-    { class, aspect-chain }:
+    { HM-OS-HOST }:
     let
+      inherit (HM-OS-HOST) OS host;
+
       hmClass = "homeManager";
       hmUsers = builtins.filter (u: u.class == hmClass) (lib.attrValues host.users);
 
       hmUserModule =
         user:
         let
-          ctx = {
-            inherit aspect-chain;
-            class = hmClass;
-          };
           HM = den.aspects.${user.aspect};
           aspect = HM {
-            inherit host user;
-            OS-HM = { inherit OS HM; };
+            HM-OS-USER = {
+              inherit
+                OS
+                HM
+                host
+                user
+                ;
+            };
           };
-          module = aspect.resolve ctx;
+          module = aspect.resolve { class = hmClass; };
         in
         module;
 
@@ -53,19 +56,14 @@ let
         value.imports = [ (hmUserModule user) ];
       }) hmUsers;
 
-      hmModule = host.hm-module or inputs.home-manager."${class}Modules".home-manager;
-      aspect.${class} = {
+      hmModule = host.hm-module or inputs.home-manager."${host.class}Modules".home-manager;
+      aspect.${host.class} = {
         imports = [ hmModule ];
         home-manager.users = lib.listToAttrs users;
       };
 
-      supportedOS = builtins.elem class [
-        "nixos"
-        "darwin"
-      ];
-      enabled = supportedOS && builtins.length hmUsers > 0;
     in
-    if enabled then aspect else { };
+    aspect;
 
 in
 {

modules/aspects/provides/home-manager/hm-os-host.nix

@@ -0,0 +1,43 @@
+{ den, lib, ... }:
+let
+  description = ''
+    This is a private aspect always included in den.default.
+
+    This aspect detects hosts that have an HM supported OS and
+    that have at least one user with ${hm-class} class.
+
+    When this occurs it produces a context `HM-OS-HOST`
+    that other host aspects can use.
+
+    When the `den._.home-manager` aspect is enabled by the user,
+    it reacts to this context and configures HM on the host.
+
+    This same context can be used by other aspects to configure
+    OS settings ONLY for hosts having HM enabled.
+  '';
+
+  hm-class = "homeManager";
+  hm-os-classes = [
+    "nixos"
+    "darwin"
+  ];
+
+  hm-detect =
+    { OS, host }:
+    let
+      is-os-supported = builtins.elem host.class hm-os-classes;
+      hm-users = builtins.filter (u: u.class == hm-class) (lib.attrValues host.users);
+      has-hm-users = builtins.length hm-users > 0;
+      is-hm-host = is-os-supported && has-hm-users;
+      ctx.HM-OS-HOST = { inherit OS host; };
+    in
+    if is-hm-host then OS ctx else { };
+
+  aspect = {
+    inherit description;
+    __functor = _: den.lib.take.exactly hm-detect;
+  };
+in
+{
+  den.default.includes = [ aspect ];
+}

templates/examples/modules/_example/ci/hm-enabled-host.nix

@@ -0,0 +1,29 @@
+{ den, inputs, ... }:
+{
+  # The `{ HM-OS-HOST }` context is activated ONLY for hosts that have
+  # a HM supported OS and at least one user with homeManager class.
+  den.aspects.hm-global-pkgs =
+    { HM-OS-HOST }:
+    den.lib.take.unused [ HM-OS-HOST.host ] # access host from context if needed
+      {
+        nixos.home-manager.useGlobalPkgs = true;
+      };
+
+  den.default.includes = [ den.aspects.hm-global-pkgs ];
+
+  den.hosts.x86_64-linux.no-homes = { };
+
+  perSystem =
+    { checkCond, rockhopper, ... }:
+    {
+      checks.rockhopper-hm-global-pkgs = checkCond "rockhopper-hm-global-pkgs" (
+        rockhopper.config.home-manager.useGlobalPkgs
+      );
+
+      checks.no-homes-hm-global-pkgs = checkCond "no-homes-hm-global-pkgs" (
+        # no home-manager enabled nor useGlobalPkgs
+        !inputs.self.nixosConfigurations.no-homes.config ? home-manager.useGlobalPkgs
+      );
+    };
+
+}

templates/examples/modules/_example/ci/top-level-parametric.nix

@@ -22,8 +22,11 @@ in
       homeManager.imports = [ (topLevel host.name) ];
     };
 
-  den.aspects.alice.includes = [
+  den.aspects.rockhopper.includes = [
     den.aspects.toplevel-host
+  ];
+
+  den.aspects.alice.includes = [
     den.aspects.toplevel-user
   ];