From 432bf31327c6b9647acb8bdb0eac2d392fd9f60a Mon Sep 17 00:00:00 2001 From: Petr Viktorin Date: Fri, 13 Sep 2024 13:18:49 +0200 Subject: [PATCH] gh-123909: PyType_From*: Disallow metaclasses with custom tp_new (GH-123947) --- Doc/c-api/type.rst | 24 +++++++++--- Lib/test/test_capi/test_misc.py | 12 ++---- ...-09-10-16-54-27.gh-issue-123909.CTGxDR.rst | 3 ++ Objects/typeobject.c | 38 +++++-------------- 4 files changed, 34 insertions(+), 43 deletions(-) create mode 100644 Misc/NEWS.d/next/C_API/2024-09-10-16-54-27.gh-issue-123909.CTGxDR.rst diff --git a/Doc/c-api/type.rst b/Doc/c-api/type.rst index 0cae5c09505..fa04d6c0ad5 100644 --- a/Doc/c-api/type.rst +++ b/Doc/c-api/type.rst @@ -345,8 +345,12 @@ The following functions and structs are used to create The :c:member:`~PyTypeObject.tp_new` of the metaclass is *ignored*. which may result in incomplete initialization. Creating classes whose metaclass overrides - :c:member:`~PyTypeObject.tp_new` is deprecated and in Python 3.14+ it - will be no longer allowed. + :c:member:`~PyTypeObject.tp_new` is deprecated. + + .. versionchanged:: 3.14 + + Creating classes whose metaclass overrides + :c:member:`~PyTypeObject.tp_new` is no longer allowed. .. c:function:: PyObject* PyType_FromSpecWithBases(PyType_Spec *spec, PyObject *bases) @@ -362,8 +366,12 @@ The following functions and structs are used to create The :c:member:`~PyTypeObject.tp_new` of the metaclass is *ignored*. which may result in incomplete initialization. Creating classes whose metaclass overrides - :c:member:`~PyTypeObject.tp_new` is deprecated and in Python 3.14+ it - will be no longer allowed. + :c:member:`~PyTypeObject.tp_new` is deprecated. + + .. versionchanged:: 3.14 + + Creating classes whose metaclass overrides + :c:member:`~PyTypeObject.tp_new` is no longer allowed. .. c:function:: PyObject* PyType_FromSpec(PyType_Spec *spec) @@ -378,8 +386,12 @@ The following functions and structs are used to create The :c:member:`~PyTypeObject.tp_new` of the metaclass is *ignored*. which may result in incomplete initialization. Creating classes whose metaclass overrides - :c:member:`~PyTypeObject.tp_new` is deprecated and in Python 3.14+ it - will be no longer allowed. + :c:member:`~PyTypeObject.tp_new` is deprecated. + + .. versionchanged:: 3.14 + + Creating classes whose metaclass overrides + :c:member:`~PyTypeObject.tp_new` is no longer allowed. .. raw:: html diff --git a/Lib/test/test_capi/test_misc.py b/Lib/test/test_capi/test_misc.py index d50217b6959..18392c4fce5 100644 --- a/Lib/test/test_capi/test_misc.py +++ b/Lib/test/test_capi/test_misc.py @@ -722,22 +722,16 @@ class CAPITest(unittest.TestCase): with self.assertRaisesRegex(TypeError, msg): t = _testcapi.pytype_fromspec_meta(metaclass) - def test_heaptype_with_custom_metaclass_deprecation(self): + def test_heaptype_base_with_custom_metaclass(self): metaclass = _testcapi.HeapCTypeMetaclassCustomNew - # gh-103968: a metaclass with custom tp_new is deprecated, but still - # allowed for functions that existed in 3.11 - # (PyType_FromSpecWithBases is used here). class Base(metaclass=metaclass): pass # Class creation from C - with warnings_helper.check_warnings( - ('.* _testcapi.Subclass .* custom tp_new.*in Python 3.14.*', DeprecationWarning), - ): + msg = "Metaclasses with custom tp_new are not supported." + with self.assertRaisesRegex(TypeError, msg): sub = _testcapi.make_type_with_base(Base) - self.assertTrue(issubclass(sub, Base)) - self.assertIsInstance(sub, metaclass) def test_multiple_inheritance_ctypes_with_weakref_or_dict(self): for weakref_cls in (_testcapi.HeapCTypeWithWeakref, diff --git a/Misc/NEWS.d/next/C_API/2024-09-10-16-54-27.gh-issue-123909.CTGxDR.rst b/Misc/NEWS.d/next/C_API/2024-09-10-16-54-27.gh-issue-123909.CTGxDR.rst new file mode 100644 index 00000000000..b7a4913abbc --- /dev/null +++ b/Misc/NEWS.d/next/C_API/2024-09-10-16-54-27.gh-issue-123909.CTGxDR.rst @@ -0,0 +1,3 @@ +:c:func:`PyType_FromSpec`, :c:func:`PyType_FromSpecWithBases` and +:c:func:`PyType_FromModuleAndSpec` will now fail if the metaclass of the new +type has custom :c:member:`~PyTypeObject.tp_new`. diff --git a/Objects/typeobject.c b/Objects/typeobject.c index a6483f74b79..28edd801284 100644 --- a/Objects/typeobject.c +++ b/Objects/typeobject.c @@ -4668,10 +4668,10 @@ special_offset_from_member( return -1; } -static PyObject * -_PyType_FromMetaclass_impl( +PyObject * +PyType_FromMetaclass( PyTypeObject *metaclass, PyObject *module, - PyType_Spec *spec, PyObject *bases_in, int _allow_tp_new) + PyType_Spec *spec, PyObject *bases_in) { /* Invariant: A non-NULL value in one of these means this function holds * a strong reference or owns allocated memory. @@ -4848,21 +4848,10 @@ _PyType_FromMetaclass_impl( goto finally; } if (metaclass->tp_new && metaclass->tp_new != PyType_Type.tp_new) { - if (_allow_tp_new) { - if (PyErr_WarnFormat( - PyExc_DeprecationWarning, 1, - "Type %s uses PyType_Spec with a metaclass that has custom " - "tp_new. This is deprecated and will no longer be allowed in " - "Python 3.14.", spec->name) < 0) { - goto finally; - } - } - else { - PyErr_SetString( - PyExc_TypeError, - "Metaclasses with custom tp_new are not supported."); - goto finally; - } + PyErr_SetString( + PyExc_TypeError, + "Metaclasses with custom tp_new are not supported."); + goto finally; } /* Calculate best base, and check that all bases are type objects */ @@ -5109,29 +5098,22 @@ _PyType_FromMetaclass_impl( return (PyObject*)res; } -PyObject * -PyType_FromMetaclass(PyTypeObject *metaclass, PyObject *module, - PyType_Spec *spec, PyObject *bases_in) -{ - return _PyType_FromMetaclass_impl(metaclass, module, spec, bases_in, 0); -} - PyObject * PyType_FromModuleAndSpec(PyObject *module, PyType_Spec *spec, PyObject *bases) { - return _PyType_FromMetaclass_impl(NULL, module, spec, bases, 1); + return PyType_FromMetaclass(NULL, module, spec, bases); } PyObject * PyType_FromSpecWithBases(PyType_Spec *spec, PyObject *bases) { - return _PyType_FromMetaclass_impl(NULL, NULL, spec, bases, 1); + return PyType_FromMetaclass(NULL, NULL, spec, bases); } PyObject * PyType_FromSpec(PyType_Spec *spec) { - return _PyType_FromMetaclass_impl(NULL, NULL, spec, NULL, 1); + return PyType_FromMetaclass(NULL, NULL, spec, NULL); } PyObject *