diff --git a/Lib/test/test_abc.py b/Lib/test/test_abc.py index f43123fa24e..0fa40cb4304 100644 --- a/Lib/test/test_abc.py +++ b/Lib/test/test_abc.py @@ -60,6 +60,26 @@ 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_metaclass_abc(self): + # Metaclasses can be ABCs, too. + class A(metaclass=abc.ABCMeta): + @abc.abstractmethod + def x(self): + pass + self.assertEqual(A.__abstractmethods__, {"x"}) + class meta(type, A): + def x(self): + return 1 + class C(metaclass=meta): + pass + def test_registration_basics(self): class A(metaclass=abc.ABCMeta): pass diff --git a/Misc/NEWS b/Misc/NEWS index d9d4a0e3648..58417615b82 100644 --- a/Misc/NEWS +++ b/Misc/NEWS @@ -12,6 +12,9 @@ What's New in Python 3.1.3? Core and Builtins ----------------- +- Issue #10006: type.__abstractmethods__ now raises an AttributeError. As a + result metaclasses can now be ABCs (see #9533). + - Issue #9930: Remove bogus subtype check that was causing (e.g.) float.__rdiv__(2.0, 3) to return NotImplemented instead of the expected 1.5. diff --git a/Objects/typeobject.c b/Objects/typeobject.c index ab942c0b97b..d2eb8e27fe8 100644 --- a/Objects/typeobject.c +++ b/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, - "__abstractmethods__"); + PyObject *mod = NULL; + /* 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;