refactor(nix): use balanced attrset merges

Replace directory-derived attrset merge folds with mergeAttrsList so dynamic generated maps do not repeatedly copy the growing accumulator during evaluation.

Author: khaneliman

flake/dev/devshells.nix

@@ -41,6 +41,6 @@
       };
     in
     {
-      devShells = lib.foldl' (acc: name: acc // buildShell name) dotnetShells shellNames;
+      devShells = lib.attrsets.mergeAttrsList ([ dotnetShells ] ++ map buildShell shellNames);
     };
 }

lib/file/default.nix

@@ -26,7 +26,7 @@ let
 
   listNamesMatching' = predicate: dirPath: lib.filter predicate (listNames' dirPath);
 
-  mergeAttrs' = attrsList: lib.foldl' (acc: attrs: acc // attrs) { } attrsList;
+  mergeAttrs' = lib.attrsets.mergeAttrsList;
 in
 {
   /**
@@ -329,7 +329,7 @@ in
           path = systemPath + "/${hostname}";
         });
     in
-    builtins.foldl' (acc: system: acc // generateSystemConfigs system) { } systemArchs;
+    mergeAttrs' (map generateSystemConfigs systemArchs);
 
   /**
     Filter systems for NixOS (Linux).
@@ -402,5 +402,5 @@ in
         in
         genAttrs userAtHosts parseUserAtHost;
     in
-    builtins.foldl' (acc: system: acc // generateHomeConfigs system) { } systemArchs;
+    mergeAttrs' (map generateHomeConfigs systemArchs);
 }

packages/wallpapers/package.nix

@@ -35,16 +35,20 @@ let
     if lib.length splitName > 1 then lib.concatStringsSep "." (lib.init splitName) else baseName;
 
   names = map getFileNameWithoutExtension images;
-  wallpapers = lib.foldl (
-    acc: image:
-    let
-      # fileName = builtins.baseNameOf image;
-      # Get the basename of the file and then take the name before the file extension.
-      # eg. mywallpaper.png -> mywallpaper
-      name = getFileNameWithoutExtension image;
-    in
-    acc // { "${name}" = mkWallpaper name (./assets + "/${image}"); }
-  ) { } images;
+  wallpapers = lib.attrsets.mergeAttrsList (
+    map (
+      image:
+      let
+        # fileName = builtins.baseNameOf image;
+        # Get the basename of the file and then take the name before the file extension.
+        # eg. mywallpaper.png -> mywallpaper
+        name = getFileNameWithoutExtension image;
+      in
+      {
+        "${name}" = mkWallpaper name (./assets + "/${image}");
+      }
+    ) images
+  );
   installTarget = "$out/share/wallpapers";
 in
 stdenvNoCC.mkDerivation {