refactor(system): reuse parsed home configs

Parse home configuration metadata once while generating flake system outputs and pass matching homes into each system builder. Keep the existing fallback for direct mkSystem and mkDarwin callers.

Author: khaneliman

flake/configs.nix

@@ -5,10 +5,22 @@
   ...
 }:
 let
-  inherit (self.lib.file) parseSystemConfigurations filterNixOSSystems filterDarwinSystems;
+  inherit (self.lib.file)
+    filterDarwinSystems
+    filterNixOSSystems
+    parseHomeConfigurations
+    parseSystemConfigurations
+    ;
 
   systemsPath = ../systems;
+  homesPath = ../homes;
   allSystems = parseSystemConfigurations systemsPath;
+  allHomes = parseHomeConfigurations homesPath;
+  matchingHomes =
+    system: hostname:
+    lib.filterAttrs (
+      _name: homeConfig: homeConfig.system == system && homeConfig.hostname == hostname
+    ) allHomes;
 in
 {
   flake = {
@@ -20,6 +32,7 @@ in
         value = self.lib.system.mkSystem {
           inherit inputs system hostname;
           username = "khaneliman";
+          matchingHomes = matchingHomes system hostname;
         };
       }
     ) (filterNixOSSystems allSystems);
@@ -32,6 +45,7 @@ in
         value = self.lib.system.mkDarwin {
           inherit inputs system hostname;
           username = "khaneliman";
+          matchingHomes = matchingHomes system hostname;
         };
       }
     ) (filterDarwinSystems allSystems);

lib/system/mk-darwin.nix

@@ -24,6 +24,7 @@
   system,
   hostname,
   username ? "khaneliman",
+  matchingHomes ? null,
   modules ? [ ],
   ...
 }:
@@ -35,22 +36,26 @@ let
   inputPackageSets = common.mkInputPackageSets {
     inherit flake system;
   };
-  matchingHomes = common.mkHomeConfigs {
-    inherit
-      flake
-      system
-      hostname
-      ;
-  };
+  resolvedMatchingHomes =
+    if matchingHomes == null then
+      common.mkHomeConfigs {
+        inherit
+          flake
+          system
+          hostname
+          ;
+      }
+    else
+      matchingHomes;
   homeManagerConfig = common.mkHomeManagerConfig {
     inherit
       extendedLib
       inputs
       system
       hostname
-      matchingHomes
       inputPackageSets
       ;
+    matchingHomes = resolvedMatchingHomes;
     isNixOS = false;
   };
 in

lib/system/mk-system.nix

@@ -24,6 +24,7 @@
   system,
   hostname,
   username ? "khaneliman",
+  matchingHomes ? null,
   modules ? [ ],
   ...
 }:
@@ -35,22 +36,26 @@ let
   inputPackageSets = common.mkInputPackageSets {
     inherit flake system;
   };
-  matchingHomes = common.mkHomeConfigs {
-    inherit
-      flake
-      system
-      hostname
-      ;
-  };
+  resolvedMatchingHomes =
+    if matchingHomes == null then
+      common.mkHomeConfigs {
+        inherit
+          flake
+          system
+          hostname
+          ;
+      }
+    else
+      matchingHomes;
   homeManagerConfig = common.mkHomeManagerConfig {
     inherit
       extendedLib
       inputs
       system
       hostname
-      matchingHomes
       inputPackageSets
       ;
+    matchingHomes = resolvedMatchingHomes;
     isNixOS = true;
   };
 in