From c393ee858932f79bd6dabf31550f9a53ea90bc68 Mon Sep 17 00:00:00 2001 From: Xiang Zhang Date: Wed, 8 Mar 2017 11:18:49 +0800 Subject: [PATCH] bpo-24329: allow __qualname__ and __classcell__ in __slots__ (GH-495) --- Lib/test/test_descr.py | 40 ++++++++++++++++++++++++++++++++++++++++ Objects/typeobject.c | 16 +++++++++++----- 2 files changed, 51 insertions(+), 5 deletions(-) diff --git a/Lib/test/test_descr.py b/Lib/test/test_descr.py index 5da7ae598c..92553e3573 100644 --- a/Lib/test/test_descr.py +++ b/Lib/test/test_descr.py @@ -1322,6 +1322,46 @@ order (MRO) for bases """ a.foo = 42 self.assertEqual(a.__dict__, {"foo": 42}) + def test_slots_special2(self): + # Testing __qualname__ and __classcell__ in __slots__ + class Meta(type): + def __new__(cls, name, bases, namespace, attr): + self.assertIn(attr, namespace) + return super().__new__(cls, name, bases, namespace) + + class C1: + def __init__(self): + self.b = 42 + class C2(C1, metaclass=Meta, attr="__classcell__"): + __slots__ = ["__classcell__"] + def __init__(self): + super().__init__() + self.assertIsInstance(C2.__dict__["__classcell__"], + types.MemberDescriptorType) + c = C2() + self.assertEqual(c.b, 42) + self.assertNotHasAttr(c, "__classcell__") + c.__classcell__ = 42 + self.assertEqual(c.__classcell__, 42) + with self.assertRaises(TypeError): + class C3: + __classcell__ = 42 + __slots__ = ["__classcell__"] + + class Q1(metaclass=Meta, attr="__qualname__"): + __slots__ = ["__qualname__"] + self.assertEqual(Q1.__qualname__, C1.__qualname__[:-2] + "Q1") + self.assertIsInstance(Q1.__dict__["__qualname__"], + types.MemberDescriptorType) + q = Q1() + self.assertNotHasAttr(q, "__qualname__") + q.__qualname__ = "q" + self.assertEqual(q.__qualname__, "q") + with self.assertRaises(TypeError): + class Q2: + __qualname__ = object() + __slots__ = ["__qualname__"] + def test_slots_descriptor(self): # Issue2115: slot descriptors did not correctly check # the type of the given object diff --git a/Objects/typeobject.c b/Objects/typeobject.c index 18b67c8325..d70ced04bf 100644 --- a/Objects/typeobject.c +++ b/Objects/typeobject.c @@ -2478,11 +2478,17 @@ type_new(PyTypeObject *metatype, PyObject *args, PyObject *kwds) } PyList_SET_ITEM(newslots, j, tmp); if (PyDict_GetItem(dict, tmp)) { - PyErr_Format(PyExc_ValueError, - "%R in __slots__ conflicts with class variable", - tmp); - Py_DECREF(newslots); - goto error; + /* CPython inserts __qualname__ and __classcell__ (when needed) + into the namespace when creating a class. They will be deleted + below so won't act as class variables. */ + if (!_PyUnicode_EqualToASCIIId(tmp, &PyId___qualname__) && + !_PyUnicode_EqualToASCIIId(tmp, &PyId___classcell__)) { + PyErr_Format(PyExc_ValueError, + "%R in __slots__ conflicts with class variable", + tmp); + Py_DECREF(newslots); + goto error; + } } j++; } -- 2.40.0