revert(dotfiles): share Nix file discovery

src/dotfiles/default.nix

@@ -17,7 +17,7 @@ let
   util = import ./util.nix { inherit lib; };
 
   registry = import ./registry.nix {
-    inherit lib util;
+    inherit lib;
     hosts = self.nixosConfigurations;
     root = root + "/registry";
   };

src/dotfiles/guests.nix

@@ -8,7 +8,6 @@
   util,
 }:
 let
-  files = util.collectNixFiles root;
   mkGuest =
     name:
     { config, lib, ... }:
@@ -168,22 +167,22 @@ let
       config = lib.mkIf cfg.enable {
         assertions =
           let
+            hasDirectorySettings = mount: mount.owner != null || mount.group != null || mount.mode != null;
+            hasCompleteDirectorySettings =
+              mount: mount.owner != null && mount.group != null && mount.mode != null;
+            hasOneSource = mount: (mount.directory != null) != (mount.file != null);
             mountsWithInvalidSource = lib.attrNames (
               lib.filterAttrs (_: mount: !hasOneSource mount) cfg.mounts
             );
-            hasOneSource = mount: (mount.directory != null) != (mount.file != null);
             fileMountsWithHostSettings = lib.attrNames (
               lib.filterAttrs (_: mount: mount.file != null && hasDirectorySettings mount) cfg.mounts
             );
-            hasDirectorySettings = mount: mount.owner != null || mount.group != null || mount.mode != null;
             directoryMountsWithPartialHostSettings = lib.attrNames (
               lib.filterAttrs (
                 _: mount:
                 mount.directory != null && hasDirectorySettings mount && !hasCompleteDirectorySettings mount
               ) cfg.mounts
             );
-            hasCompleteDirectorySettings =
-              mount: mount.owner != null && mount.group != null && mount.mode != null;
           in
           [
             {
@@ -276,7 +275,11 @@ let
       };
     };
 
-  names = map (path: lib.removeSuffix ".nix" (builtins.baseNameOf path)) files;
+  files = util.collectNixFiles root;
+  guestFiles = lib.filterAttrs (file: type: type == "regular" && lib.hasSuffix ".nix" file) (
+    builtins.readDir root
+  );
+  names = map (file: lib.removeSuffix ".nix" file) (lib.attrNames guestFiles);
 in
 {
   imports = files ++ map mkGuest names;

src/dotfiles/registry.nix

@@ -2,14 +2,20 @@
   hosts,
   lib,
   root,
-  util,
 }:
 let
-  definitions = lib.listToAttrs (
-    map (path: lib.nameValuePair (registryName (builtins.baseNameOf path)) (mkRegistry path)) (
-      util.collectNixFiles root
-    )
-  );
+  definitions =
+    lib.mapAttrs'
+      (
+        name: _type:
+        let
+          path = root + "/${name}";
+        in
+        lib.nameValuePair (registryName name) (mkRegistry path)
+      )
+      (
+        lib.filterAttrs (name: type: type == "regular" && lib.hasSuffix ".nix" name) (builtins.readDir root)
+      );
 
   registryName = fileName: lib.removeSuffix ".nix" fileName;