Suppress false-positive not-callable messages from class descriptors

This is a holdover until astroid can be fixed. Astroid needs to understand descriptors or at least raise Uninferable instead of allowing the descriptor instance through Close #1699

Author: brycepg

pylint/checkers/typecheck.py

@@ -875,8 +875,12 @@ def visit_call(self, node):
 
  called = safe_infer(node.func)
  # only function, generator and object defining __call__ are allowed
+ # Ignore instances of descriptors since astroid cannot properly handle them
+ # yet
  if called and not called.callable():
- if isinstance(called, astroid.Instance) and not has_known_bases(called):
+ if isinstance(called, astroid.Instance) and (not has_known_bases(called)
+ or (isinstance(called.scope(), astroid.ClassDef)
+ and '__get__' in called.locals)):
  # Don't emit if we can't make sure this object is callable.
  pass
  else:

pylint/test/unittest_checker_typecheck.py

@@ -229,3 +229,19 @@ def test_typing_namedtuple_unsubscriptable_object_issue1295(self):
  subscript = module.body[-1].value
  with self.assertNoMessages():
  self.checker.visit_subscript(subscript)
+
+ def test_staticmethod_multiprocessing_call(self):
+ """Make sure not-callable isn't raised for descriptors
+
+ astroid can't process descriptors correctly so
+ pylint needs to ignore not-callable for them
+ right now
+
+ Test for https://github.com/PyCQA/pylint/issues/1699
+ """
+ call = astroid.extract_node("""
+ import multiprocessing
+ multiprocessing.current_process() #@
+ """)
+ with self.assertNoMessages():
+ self.checker.visit_call(call)