Fix incorrect scope for functools partials (#1097)

* Use scope parent
* Do not set name onto parent frame for partials
* Add test case that captures broken scopes

Author: Alphadelta14

astroid/brain/brain_functools.py

@@ -103,7 +103,7 @@ def _functools_partial_inference(node, context=None):
         doc=inferred_wrapped_function.doc,
         lineno=inferred_wrapped_function.lineno,
         col_offset=inferred_wrapped_function.col_offset,
-        parent=inferred_wrapped_function.parent,
+        parent=node.parent,
     )
     partial_function.postinit(
         args=inferred_wrapped_function.args,

astroid/node_classes.py

@@ -1209,16 +1209,8 @@ def _filter_stmts(self, stmts, frame, offset):
                 # want to clear previous assignments if any (hence the test on
                 # optional_assign)
                 if not (optional_assign or are_exclusive(_stmts[pindex], node)):
-                    if (
-                        # In case of partial function node, if the statement is different
-                        # from the origin function then it can be deleted otherwise it should
-                        # remain to be able to correctly infer the call to origin function.
-                        not node.is_function
-                        or node.qname() != "PartialFunction"
-                        or node.name != _stmts[pindex].name
-                    ):
-                        del _stmt_parents[pindex]
-                        del _stmts[pindex]
+                    del _stmt_parents[pindex]
+                    del _stmts[pindex]
             if isinstance(node, AssignName):
                 if not optional_assign and stmt.parent is mystmt.parent:
                     _stmts = []

astroid/objects.py

@@ -260,7 +260,10 @@ class PartialFunction(scoped_nodes.FunctionDef):
     def __init__(
         self, call, name=None, doc=None, lineno=None, col_offset=None, parent=None
     ):
-        super().__init__(name, doc, lineno, col_offset, parent)
+        super().__init__(name, doc, lineno, col_offset, parent=None)
+        # A typical FunctionDef automatically adds its name to the parent scope,
+        # but a partial should not, so defer setting parent until after init
+        self.parent = parent
         self.filled_positionals = len(call.positional_arguments[1:])
         self.filled_args = call.positional_arguments[1:]
         self.filled_keywords = call.keyword_arguments

tests/unittest_brain.py

@@ -2761,6 +2761,46 @@ def other_test(a, b, *, c=1):
             assert isinstance(inferred, astroid.Const)
             assert inferred.value == expected_value
 
+    def test_partial_assignment(self):
+        """Make sure partials are not assigned to original scope."""
+        ast_nodes = astroid.extract_node(
+            """
+        from functools import partial
+        def test(a, b): #@
+            return a + b
+        test2 = partial(test, 1)
+        test2 #@
+        def test3_scope(a):
+            test3 = partial(test, a)
+            test3 #@
+        """
+        )
+        func1, func2, func3 = ast_nodes
+        assert func1.parent.scope() == func2.parent.scope()
+        assert func1.parent.scope() != func3.parent.scope()
+        partial_func3 = next(func3.infer())
+        # use scope of parent, so that it doesn't just refer to self
+        scope = partial_func3.parent.scope()
+        assert scope.name == "test3_scope", "parented by closure"
+
+    def test_partial_does_not_affect_scope(self):
+        """Make sure partials are not automatically assigned."""
+        ast_nodes = astroid.extract_node(
+            """
+        from functools import partial
+        def test(a, b):
+            return a + b
+        def scope():
+            test2 = partial(test, 1)
+            test2 #@
+        """
+        )
+        test2 = next(ast_nodes.infer())
+        mod_scope = test2.root()
+        scope = test2.parent.scope()
+        assert set(mod_scope) == {"test", "scope", "partial"}
+        assert set(scope) == {"test2"}
+
 
 def test_http_client_brain():
     node = astroid.extract_node(