bpo-38689: avoid IDLE hanging when calltip fails getting a signature (GH-17152)

Inspect.signature failed on the test case because its isinstance call raised.

1 files changed, 17 insertions, 7 deletions

diff --git a/Lib/idlelib/idle_test/test_calltip.py b/Lib/idlelib/idle_test/test_calltip.py
index 886959b..d386b5c 100644
--- a/Lib/idlelib/idle_test/test_calltip.py
+++ b/Lib/idlelib/idle_test/test_calltip.py
@@ -219,20 +219,30 @@ bytes() -> empty bytes object''')
             with self.subTest(meth=meth, mtip=mtip):
                 self.assertEqual(get_spec(meth), mtip)
 
-    def test_attribute_exception(self):
+    def test_buggy_getattr_class(self):
         class NoCall:
-            def __getattr__(self, name):
-                raise BaseException
+            def __getattr__(self, name):  # Not invoked for class attribute.
+                raise IndexError  # Bug.
         class CallA(NoCall):
-            def __call__(oui, a, b, c):
+            def __call__(self, ci):  # Bug does not matter.
                 pass
         class CallB(NoCall):
-            def __call__(self, ci):
+            def __call__(oui, a, b, c):  # Non-standard 'self'.
                 pass
 
         for meth, mtip  in ((NoCall, default_tip), (CallA, default_tip),
-                            (NoCall(), ''), (CallA(), '(a, b, c)'),
-                            (CallB(), '(ci)')):
+                            (NoCall(), ''), (CallA(), '(ci)'),
+                            (CallB(), '(a, b, c)')):
+            with self.subTest(meth=meth, mtip=mtip):
+                self.assertEqual(get_spec(meth), mtip)
+
+    def test_metaclass_class(self):  # Failure case for issue 38689.
+        class Type(type):  # Type() requires 3 type args, returns class.
+            __class__ = property({}.__getitem__, {}.__setitem__)
+        class Object(metaclass=Type):
+            __slots__ = '__class__'
+        for meth, mtip  in ((Type, default_tip), (Object, default_tip),
+                            (Object(), '')):
             with self.subTest(meth=meth, mtip=mtip):
                 self.assertEqual(get_spec(meth), mtip)