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| author | Benjamin Peterson <benjamin@python.org> | 2015-10-06 19:36:54 -0700 |
|---|---|---|
| committer | Benjamin Peterson <benjamin@python.org> | 2015-10-06 19:36:54 -0700 |
| commit | 07929c5f6dd69c554889910bf5988ad6c31f5593 (patch) | |
| tree | a87723762c0d0aef4efd3b4bc2e64957272f22cb | |
| parent | 0235004e863b2a2f3812d04cd7820f33ab6d5687 (diff) | |
| download | cpython-07929c5f6dd69c554889910bf5988ad6c31f5593.tar.gz | |
prevent unacceptable bases from becoming bases through multiple inheritance (#24806)
| -rw-r--r-- | Lib/test/test_descr.py | 31 | ||||
| -rw-r--r-- | Misc/NEWS | 3 | ||||
| -rw-r--r-- | Objects/typeobject.c | 12 |
3 files changed, 40 insertions, 6 deletions
diff --git a/Lib/test/test_descr.py b/Lib/test/test_descr.py index 9a60a12c29..adce6e5905 100644 --- a/Lib/test/test_descr.py +++ b/Lib/test/test_descr.py @@ -3735,6 +3735,37 @@ order (MRO) for bases """ else: assert 0, "best_base calculation found wanting" + def test_unsubclassable_types(self): + with self.assertRaises(TypeError): + class X(type(None)): + pass + with self.assertRaises(TypeError): + class X(object, type(None)): + pass + with self.assertRaises(TypeError): + class X(type(None), object): + pass + class O(object): + pass + with self.assertRaises(TypeError): + class X(O, type(None)): + pass + with self.assertRaises(TypeError): + class X(type(None), O): + pass + + class X(object): + pass + with self.assertRaises(TypeError): + X.__bases__ = type(None), + with self.assertRaises(TypeError): + X.__bases__ = object, type(None) + with self.assertRaises(TypeError): + X.__bases__ = type(None), object + with self.assertRaises(TypeError): + X.__bases__ = O, type(None) + with self.assertRaises(TypeError): + X.__bases__ = type(None), O def test_mutable_bases_with_failing_mro(self): # Testing mutable bases with failing mro... @@ -10,6 +10,9 @@ Release date: tba Core and Builtins ----------------- +- Issue #24806: Prevent builtin types that are not allowed to be subclassed from + being subclassed through multiple inheritance. + - Issue #24848: Fixed a number of bugs in UTF-7 decoding of misformed data. - Issue #25280: Import trace messages emitted in verbose (-v) mode are no diff --git a/Objects/typeobject.c b/Objects/typeobject.c index d39c9431ea..cf4e4e57da 100644 --- a/Objects/typeobject.c +++ b/Objects/typeobject.c @@ -1937,6 +1937,12 @@ best_base(PyObject *bases) if (PyType_Ready(base_i) < 0) return NULL; } + if (!PyType_HasFeature(base_i, Py_TPFLAGS_BASETYPE)) { + PyErr_Format(PyExc_TypeError, + "type '%.100s' is not an acceptable base type", + base_i->tp_name); + return NULL; + } candidate = solid_base(base_i); if (winner == NULL) { winner = candidate; @@ -2317,12 +2323,6 @@ type_new(PyTypeObject *metatype, PyObject *args, PyObject *kwds) if (base == NULL) { goto error; } - if (!PyType_HasFeature(base, Py_TPFLAGS_BASETYPE)) { - PyErr_Format(PyExc_TypeError, - "type '%.100s' is not an acceptable base type", - base->tp_name); - goto error; - } dict = PyDict_Copy(orig_dict); if (dict == NULL) |