type.__abstractmethods__ should raise an AttributeError #10006

Lib/test/test_abc.py

@@ -98,6 +98,13 @@ class TestABC(unittest.TestCase):
             self.assertRaises(TypeError, F)  # because bar is abstract now
             self.assertTrue(isabstract(F))
 
+    def test_type_has_no_abstractmethods(self):
+        # type pretends not to have __abstractmethods__.
+        self.assertRaises(AttributeError, getattr, type, "__abstractmethods__")
+        class meta(type):
+            pass
+        self.assertRaises(AttributeError, getattr, meta, "__abstractmethods__")
+
     def test_registration_basics(self):
         class A(metaclass=abc.ABCMeta):
             pass

Misc/NEWS

@@ -10,6 +10,8 @@ What's New in Python 3.2 Alpha 3?
 Core and Builtins
 -----------------
 
+- Issue #10006: type.__abstractmethods__ now raises an AttributeError.
+
 - Issue #10003: Allow handling of SIGBREAK on Windows. Fixes a regression
   introduced by issue #9324. 
 

Objects/typeobject.c

@@ -320,8 +320,11 @@ type_set_module(PyTypeObject *type, PyObject *value, void *context)
 static PyObject *
 type_abstractmethods(PyTypeObject *type, void *context)
 {
-    PyObject *mod = PyDict_GetItemString(type->tp_dict,
+    PyObject *mod = NULL;
-                                         "__abstractmethods__");
+    /* type its self has an __abstractmethods__ descriptor (this). Don't
+       return that. */
+    if (type != &PyType_Type)
+        mod = PyDict_GetItemString(type->tp_dict, "__abstractmethods__");
     if (!mod) {
         PyErr_Format(PyExc_AttributeError, "__abstractmethods__");
         return NULL;