Prevent unused-import for six.with_metaclass

pylint/checkers/variables.py

@@ -1137,9 +1137,24 @@ def visit_classdef(self, node: nodes.ClassDef) -> None:
         """Visit class: update consumption analysis variable."""
         self._to_consume.append(NamesConsumer(node, "class"))
 
-    def leave_classdef(self, _: nodes.ClassDef) -> None:
+    def leave_classdef(self, node: nodes.ClassDef) -> None:
         """Leave class: update consumption analysis variable."""
-        # do not check for not used locals here (no sense)
+        # Check for hidden ancestor names
+        # e.g. "six" in: Class X(six.with_metaclass(ABCMeta, object)):
+        for name_node in node.nodes_of_class(nodes.Name):
+            if (
+                isinstance(name_node.parent, nodes.Call)
+                and isinstance(name_node.parent.func, nodes.Attribute)
+                and isinstance(name_node.parent.func.expr, nodes.Name)
+            ):
+                hidden_name_node = name_node.parent.func.expr
+                for consumer in self._to_consume:
+                    if hidden_name_node.name in consumer.to_consume:
+                        consumer.mark_as_consumed(
+                            hidden_name_node.name,
+                            consumer.to_consume[hidden_name_node.name],
+                        )
+                        break
         self._to_consume.pop()
 
     def visit_lambda(self, node: nodes.Lambda) -> None:

tests/functional/u/unused/unused_import.py

@@ -3,13 +3,15 @@
 import xml.etree  # [unused-import]
 import xml.sax  # [unused-import]
 import os.path as test  # [unused-import]
+from abc import ABCMeta
 from sys import argv as test2  # [unused-import]
 from sys import flags  # [unused-import]
 # +1:[unused-import,unused-import]
 from collections import deque, OrderedDict, Counter
 import re, html.parser  # [unused-import]
 DATA = Counter()
 # pylint: disable=self-assigning-variable
+import six
 from fake import SomeName, SomeOtherName  # [unused-import]
 class SomeClass(object):
     SomeName = SomeName # https://bitbucket.org/logilab/pylint/issue/475
@@ -87,3 +89,6 @@ def blop(self):
 TYPE_CHECKING = False
 if TYPE_CHECKING:
     import zoneinfo
+
+class WithMetaclass(six.with_metaclass(ABCMeta, object)):
+    pass

tests/functional/u/unused/unused_import.txt

@@ -1,14 +1,14 @@
 unused-import:3:0:3:16::Unused import xml.etree:UNDEFINED
 unused-import:4:0:4:14::Unused import xml.sax:UNDEFINED
 unused-import:5:0:5:22::Unused os.path imported as test:UNDEFINED
-unused-import:6:0:6:29::Unused argv imported from sys as test2:UNDEFINED
-unused-import:7:0:7:21::Unused flags imported from sys:UNDEFINED
-unused-import:9:0:9:51::Unused OrderedDict imported from collections:UNDEFINED
-unused-import:9:0:9:51::Unused deque imported from collections:UNDEFINED
-unused-import:10:0:10:22::Unused import re:UNDEFINED
-unused-import:13:0:13:40::Unused SomeOtherName imported from fake:UNDEFINED
-unused-import:48:0:48:9::Unused import os:UNDEFINED
-unused-import:79:4:79:19::Unused import unittest:UNDEFINED
-unused-import:81:4:81:15::Unused import uuid:UNDEFINED
-unused-import:83:4:83:19::Unused import warnings:UNDEFINED
-unused-import:85:4:85:21::Unused import compileall:UNDEFINED
+unused-import:7:0:7:29::Unused argv imported from sys as test2:UNDEFINED
+unused-import:8:0:8:21::Unused flags imported from sys:UNDEFINED
+unused-import:10:0:10:51::Unused OrderedDict imported from collections:UNDEFINED
+unused-import:10:0:10:51::Unused deque imported from collections:UNDEFINED
+unused-import:11:0:11:22::Unused import re:UNDEFINED
+unused-import:15:0:15:40::Unused SomeOtherName imported from fake:UNDEFINED
+unused-import:50:0:50:9::Unused import os:UNDEFINED
+unused-import:81:4:81:19::Unused import unittest:UNDEFINED
+unused-import:83:4:83:15::Unused import uuid:UNDEFINED
+unused-import:85:4:85:19::Unused import warnings:UNDEFINED
+unused-import:87:4:87:21::Unused import compileall:UNDEFINED