Fix decorator frame

ChangeLog

@@ -29,6 +29,10 @@ Release date: TBA
 
   Refs #2860
 
+* Skip direct parent when determining the ``Decorator`` frame.
+
+  Refs pylint-dev/pylint#8425
+
 
 
 What's New in astroid 4.0.3?

astroid/nodes/node_classes.py

@@ -56,6 +56,8 @@
     from astroid import nodes
     from astroid.nodes import LocalsDictNodeNG
 
+    _FrameType = nodes.FunctionDef | nodes.Module | nodes.ClassDef | nodes.Lambda
+
 
 def _is_const(value) -> bool:
     return isinstance(value, tuple(CONST_CLS))
@@ -2239,13 +2241,22 @@ def scope(self) -> LocalsDictNodeNG:
 
         :returns: The first parent scope node.
         """
-        # skip the function node to go directly to the upper level scope
+        # skip the function or class node to go directly to the upper level scope
         if not self.parent:
             raise ParentMissingError(target=self)
         if not self.parent.parent:
             raise ParentMissingError(target=self.parent)
         return self.parent.parent.scope()
 
+    def frame(self) -> _FrameType:
+        """The first parent node defining a new frame."""
+        # skip the function or class node to go directly to the upper level frame
+        if not self.parent:
+            raise ParentMissingError(target=self)
+        if not self.parent.parent:
+            raise ParentMissingError(target=self.parent)
+        return self.parent.parent.frame()
+
     def get_children(self):
         yield from self.nodes
 

tests/test_scoped_nodes.py

@@ -2909,6 +2909,36 @@ def method():
         assert module.frame() == module
         assert module.frame() == module
 
+    @staticmethod
+    def test_frame_node_for_decorators():
+        code = builder.extract_node(
+            """
+            def deco(var): ...
+
+            @deco(
+                x := 1  #@
+            )
+            def func():  #@
+                ...
+
+            @deco(
+                y := 2  #@
+            )
+            class A:  #@
+                ...
+        """
+        )
+        name_expr_node1, func_node, name_expr_node2, class_node = code
+        module = func_node.root()
+        assert name_expr_node1.scope() == module
+        assert name_expr_node1.frame() == module
+        assert name_expr_node2.scope() == module
+        assert name_expr_node2.frame() == module
+        assert module.locals.get("x") == [name_expr_node1.target]
+        assert module.locals.get("y") == [name_expr_node2.target]
+        assert "x" not in func_node.locals
+        assert "y" not in class_node.locals
+
     @staticmethod
     def test_non_frame_node():
         """Test if the frame of non frame nodes is set correctly."""