Fix undefined-variable for __class__ in inner methods (#6957)

Author: DanielNoord

doc/whatsnew/2/2.14/full.rst

@@ -10,6 +10,11 @@ Release date: TBA
 
   Closes #2270
 
+* Fixed false positive for ``undefined-variable`` for ``__class__`` in inner methods.
+
+  Closes #4032
+
+
 What's New in Pylint 2.14.2?
 ----------------------------
 Release date: 2022-06-15

pylint/checkers/variables.py

@@ -1419,8 +1419,11 @@ def _undefined_and_used_before_checker(
                 or node.name in self.linter.config.additional_builtins
                 or (
                     node.name == "__class__"
-                    and isinstance(frame, nodes.FunctionDef)
-                    and frame.is_method()
+                    and any(
+                        i.is_method()
+                        for i in node.node_ancestors()
+                        if isinstance(i, nodes.FunctionDef)
+                    )
                 )
             )
             and not utils.node_ignores_exception(node, NameError)

tests/functional/u/undefined/undefined_variable.py

@@ -291,6 +291,12 @@ def method(self):
         # This name is not defined in the AST but it's present at runtime
         return __class__
 
+    # It is also present in inner methods
+    def method_two(self):
+        def inner_method():
+            return __class__
+
+        inner_method()
 
 def undefined_annotation(a:x): # [undefined-variable]
     if x == 2: # [used-before-assignment]

tests/functional/u/undefined/undefined_variable.txt

@@ -29,11 +29,11 @@ undefined-variable:228:25:228:37:LambdaClass4.<lambda>:Undefined variable 'Lambd
 undefined-variable:236:25:236:37:LambdaClass5.<lambda>:Undefined variable 'LambdaClass5':UNDEFINED
 used-before-assignment:257:26:257:34:func_should_fail:Using variable 'datetime' before assignment:HIGH
 undefined-variable:284:18:284:24:not_using_loop_variable_accordingly:Undefined variable 'iteree':UNDEFINED
-undefined-variable:295:27:295:28:undefined_annotation:Undefined variable 'x':UNDEFINED
-used-before-assignment:296:7:296:8:undefined_annotation:Using variable 'x' before assignment:HIGH
-undefined-variable:326:11:326:12:decorated3:Undefined variable 'x':UNDEFINED
-undefined-variable:331:19:331:20:decorated4:Undefined variable 'y':UNDEFINED
-undefined-variable:352:10:352:20:global_var_mixed_assignment:Undefined variable 'GLOBAL_VAR':HIGH
-undefined-variable:364:19:364:44:RepeatedReturnAnnotations.x:Undefined variable 'RepeatedReturnAnnotations':UNDEFINED
-undefined-variable:366:19:366:44:RepeatedReturnAnnotations.y:Undefined variable 'RepeatedReturnAnnotations':UNDEFINED
-undefined-variable:368:19:368:44:RepeatedReturnAnnotations.z:Undefined variable 'RepeatedReturnAnnotations':UNDEFINED
+undefined-variable:301:27:301:28:undefined_annotation:Undefined variable 'x':UNDEFINED
+used-before-assignment:302:7:302:8:undefined_annotation:Using variable 'x' before assignment:HIGH
+undefined-variable:332:11:332:12:decorated3:Undefined variable 'x':UNDEFINED
+undefined-variable:337:19:337:20:decorated4:Undefined variable 'y':UNDEFINED
+undefined-variable:358:10:358:20:global_var_mixed_assignment:Undefined variable 'GLOBAL_VAR':HIGH
+undefined-variable:370:19:370:44:RepeatedReturnAnnotations.x:Undefined variable 'RepeatedReturnAnnotations':UNDEFINED
+undefined-variable:372:19:372:44:RepeatedReturnAnnotations.y:Undefined variable 'RepeatedReturnAnnotations':UNDEFINED
+undefined-variable:374:19:374:44:RepeatedReturnAnnotations.z:Undefined variable 'RepeatedReturnAnnotations':UNDEFINED