feat: improve scopedImport with _file attribute and scoped in builtins

default.nix

@@ -23,16 +23,40 @@ let
           files = leaves path;
         in
         {
-          imports = if scoped == { } then files else map scoped-import files;
+          imports = if scoped == { } then files else map scoped-import-module files;
         };
 
-      scoped-import = builtins.scopedImport (
-        {
-          inherit builtins;
-          __nixPath = [ ];
-        }
-        // scoped
-      );
+      # Like builtins.scopedImport but:
+      # - include scope argument in builtins as `builtins.scoped`, for potential reuse in nested invocations
+      # - empty `__nixPath` and `builtins.nixPath` (unless explictely set in `scoped` argument)
+      scoped-import =
+        scoped:
+        builtins.scopedImport (
+          {
+            __nixPath = [ ];
+          }
+          // scoped
+          // {
+            builtins =
+              scoped.builtins or (
+                builtins
+                // {
+                  nixPath = [ ];
+                }
+              )
+              // {
+                inherit scoped;
+              };
+          }
+        );
+
+      scoped-import-module = file: {
+        # Let's not lose track of the original file even if scope-imported:
+        _file = file;
+        imports = [
+          (scoped-import scoped file)
+        ];
+      };
 
       leaves =
         let

docs/src/content/docs/reference/api.mdx

@@ -169,10 +169,21 @@ The provided attributes are merged into the scope used by `builtins.scopedImport
 Multiple `.addScoped` calls accumulate:
 
 ```nix
-import-tree (it: it.addScoped { foo = 42 }) (it: it.addScoped { bar = 99 })
+import-tree (it: it.addScoped { foo = 42 }) (it: it.addScoped { bar = 99 }) ./modules
 # modules can access both foo and bar
 ```
 
+Scoped variables can be accessed inside scoped-imported modules as `builtins.scoped`:
+
+```nix
+# module.nix
+{ 
+  imports = [ (import-tree.addScoped (builtins.scoped // { bar = foo; }) ./other-modules) ];
+  # other-modules can now access `bar` directly in addition to `foo` and `mylib`
+}
+
+```
+
 ---
 
 ## Output

tests.nix

@@ -270,6 +270,78 @@ in
       expected = 22;
     };
 
+    scoped."test access all scoped variable via scopedImport" = {
+      expr =
+        (lib.evalModules {
+          modules = [
+            (
+              (lit.addScoped {
+                foo = 22;
+                bar = "44";
+                builtins = {
+                  hello = "world";
+                };
+              })
+              ./tree/_scoped
+            )
+          ];
+        }).config.builtins.scoped;
+      expected = {
+        foo = 22;
+        bar = "44";
+        builtins = {
+          hello = "world";
+        };
+      };
+    };
+
+    scoped."test settings builtins via scopedImport" = {
+      expr =
+        (lib.evalModules {
+          modules = [
+            (
+              (lit.addScoped {
+                foo = 22;
+                bar = "44";
+                builtins = {
+                  hello = "world";
+                };
+              })
+              ./tree/_scoped
+            )
+          ];
+        }).config.builtins;
+      expected = {
+        hello = "world";
+        scoped = {
+          foo = 22;
+          bar = "44";
+          builtins = {
+            hello = "world";
+          };
+        };
+      };
+    };
+
+    scoped."test builtins.nixPath and __nixPath are empty via scopedImport" = {
+      expr =
+        let
+          eval = lib.evalModules {
+            modules = [
+              (
+                (lit.addScoped {
+                  foo = 22;
+                  bar = "44";
+                })
+                ./tree/_scoped
+              )
+            ];
+          };
+        in
+        eval.config.builtins.nixPath == [ ] && eval.config.__nixPath == [ ];
+      expected = true;
+    };
+
     combinator."test combinator syntax to compose import-tree" = {
       expr = it (it: it.withLib lib) (it: it.leaves) ./tree/_scoped;
       expected = [ ./tree/_scoped/foo.nix ];

tree/_scoped/foo.nix

@@ -1,4 +1,6 @@
 { lib, ... }:
 {
   options.foo = lib.mkOption { default = foo; };
+  options.__nixPath = lib.mkOption { default = __nixPath; };
+  options.builtins = lib.mkOption { default = builtins; };
 }