lib.packagesFromDirectoryRecursive: use explicit recursion, support n…

…ested scopes (WiP)

lib/filesystem.nix

@@ -346,10 +346,16 @@ in
     }
     => { ... }
 
-    lib.makeScope pkgs.newScope (
-      self: packagesFromDirectoryRecursive {
-        callPackage = self.callPackage;
-        directory = ./my-packages;
+
+    packagesFromDirectoryRecursive {
+      inherit (pkgs) callPackage newScope;
+      recurseIntoDirectory = f: { newScope, ... }@args:
+        lib.recurseIntoAttrset (lib.makeScope newScope (self:
+          f (args // {
+            inherit (self) callPackage newScope;
+          })
+        ));
+      directory = ./my-packages;
       }
     )
     => { ... }
@@ -361,32 +367,38 @@ in
     {
       callPackage,
       directory,
+      recurseIntoDirectory ? lib.id,
       ...
-    }:
-    assert pathIsDirectory directory;
+    }@args:
+    if !pathIsDirectory directory then
+      throw "path ${toString directory} not a directory"
+    else
     let
       inherit (lib.path) append;
       defaultPath = append directory "package.nix";
     in
     if pathIsRegularFile defaultPath then
       # if `${directory}/package.nix` exists, call it directly
       callPackage defaultPath {}
-    else lib.concatMapAttrs (name: type:
-      # otherwise, for each directory entry
-      let path = append directory name; in
-      if type == "directory" then {
-        # recurse into directories
-        "${name}" = packagesFromDirectoryRecursive {
-          inherit callPackage;
-          directory = path;
-        };
-      } else if type == "regular" && hasSuffix ".nix" name then {
-        # call .nix files
-        "${lib.removeSuffix ".nix" name}" = callPackage path {};
-      } else if type == "regular" then {
-        # ignore non-nix files
-      } else throw ''
-        lib.filesystem.packagesFromDirectoryRecursive: Unsupported file type ${type} at path ${toString path}
-      ''
-    ) (builtins.readDir directory);
+    else let
+      f = { callPackage, ... }@newArgs:
+        lib.concatMapAttrs (name: type:
+          # otherwise, for each directory entry
+          let path = append directory name; in
+          if type == "directory" then {
+            # recurse into directories
+            "${name}" = packagesFromDirectoryRecursive (newArgs // {
+              directory = path;
+            });
+          } else if type == "regular" && hasSuffix ".nix" name then {
+            # call .nix files
+            "${lib.removeSuffix ".nix" name}" = callPackage path {};
+          } else if type == "regular" then {
+            # ignore non-nix files
+          } else throw ''
+            lib.filesystem.packagesFromDirectoryRecursive: Unsupported file type ${type} at path ${toString path}
+          ''
+        ) (builtins.readDir directory);
+      in
+        recurseIntoDirectory f args;
 }