[Python-checkins] GH-92678: Fix tp_dictoffset inheritance. (GH-95596) (GH-95604)
markshannon
webhook-mailer at python.org
Thu Aug 4 07:21:46 EDT 2022
https://github.com/python/cpython/commit/2ab560105b9bfda503148e66e58d1d9a6031745e
commit: 2ab560105b9bfda503148e66e58d1d9a6031745e
branch: 3.11
author: Mark Shannon <mark at hotpy.org>
committer: markshannon <mark at hotpy.org>
date: 2022-08-04T12:21:38+01:00
summary:
GH-92678: Fix tp_dictoffset inheritance. (GH-95596) (GH-95604)
* Add test for inheriting explicit __dict__ and weakref.
* Restore 3.10 behavior for multiple inheritance of C extension classes that store their dictionary at the end of the struct.
files:
A Misc/NEWS.d/next/C API/2022-08-03-14-39-08.gh-issue-92678.ozFTEx.rst
M Lib/test/test_capi.py
M Modules/_testcapimodule.c
M Objects/typeobject.c
diff --git a/Lib/test/test_capi.py b/Lib/test/test_capi.py
index fba78fa44395..7d766ec01787 100644
--- a/Lib/test/test_capi.py
+++ b/Lib/test/test_capi.py
@@ -608,6 +608,25 @@ def test_heaptype_with_setattro(self):
del obj.value
self.assertEqual(obj.pvalue, 0)
+ def test_multiple_inheritance_ctypes_with_weakref_or_dict(self):
+
+ class Both1(_testcapi.HeapCTypeWithWeakref, _testcapi.HeapCTypeWithDict):
+ pass
+ class Both2(_testcapi.HeapCTypeWithDict, _testcapi.HeapCTypeWithWeakref):
+ pass
+
+ for cls in (_testcapi.HeapCTypeWithDict, _testcapi.HeapCTypeWithDict2,
+ _testcapi.HeapCTypeWithWeakref, _testcapi.HeapCTypeWithWeakref2):
+ for cls2 in (_testcapi.HeapCTypeWithDict, _testcapi.HeapCTypeWithDict2,
+ _testcapi.HeapCTypeWithWeakref, _testcapi.HeapCTypeWithWeakref2):
+ if cls is not cls2:
+ class S(cls, cls2):
+ pass
+ class B1(Both1, cls):
+ pass
+ class B2(Both1, cls):
+ pass
+
def test_pynumber_tobase(self):
from _testcapi import pynumber_tobase
self.assertEqual(pynumber_tobase(123, 2), '0b1111011')
diff --git a/Misc/NEWS.d/next/C API/2022-08-03-14-39-08.gh-issue-92678.ozFTEx.rst b/Misc/NEWS.d/next/C API/2022-08-03-14-39-08.gh-issue-92678.ozFTEx.rst
new file mode 100644
index 000000000000..6bf3d4b1abbf
--- /dev/null
+++ b/Misc/NEWS.d/next/C API/2022-08-03-14-39-08.gh-issue-92678.ozFTEx.rst
@@ -0,0 +1,2 @@
+Restore the 3.10 behavior for multiple inheritance of C extension classes
+that store their dictionary at the end of the struct.
diff --git a/Modules/_testcapimodule.c b/Modules/_testcapimodule.c
index 9022ee4d49a8..a394f4647156 100644
--- a/Modules/_testcapimodule.c
+++ b/Modules/_testcapimodule.c
@@ -7321,6 +7321,14 @@ static PyType_Spec HeapCTypeWithDict_spec = {
HeapCTypeWithDict_slots
};
+static PyType_Spec HeapCTypeWithDict2_spec = {
+ "_testcapi.HeapCTypeWithDict2",
+ sizeof(HeapCTypeWithDictObject),
+ 0,
+ Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE,
+ HeapCTypeWithDict_slots
+};
+
static struct PyMemberDef heapctypewithnegativedict_members[] = {
{"dictobj", T_OBJECT, offsetof(HeapCTypeWithDictObject, dict)},
{"__dictoffset__", T_PYSSIZET, -(Py_ssize_t)sizeof(void*), READONLY},
@@ -7380,6 +7388,14 @@ static PyType_Spec HeapCTypeWithWeakref_spec = {
HeapCTypeWithWeakref_slots
};
+static PyType_Spec HeapCTypeWithWeakref2_spec = {
+ "_testcapi.HeapCTypeWithWeakref2",
+ sizeof(HeapCTypeWithWeakrefObject),
+ 0,
+ Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE,
+ HeapCTypeWithWeakref_slots
+};
+
PyDoc_STRVAR(heapctypesetattr__doc__,
"A heap type without GC, but with overridden __setattr__.\n\n"
"The 'value' attribute is set to 10 in __init__ and updated via attribute setting.");
@@ -7757,6 +7773,12 @@ PyInit__testcapi(void)
}
PyModule_AddObject(m, "HeapCTypeWithDict", HeapCTypeWithDict);
+ PyObject *HeapCTypeWithDict2 = PyType_FromSpec(&HeapCTypeWithDict2_spec);
+ if (HeapCTypeWithDict2 == NULL) {
+ return -1;
+ }
+ PyModule_AddObject(m, "HeapCTypeWithDict2", HeapCTypeWithDict2);
+
PyObject *HeapCTypeWithNegativeDict = PyType_FromSpec(&HeapCTypeWithNegativeDict_spec);
if (HeapCTypeWithNegativeDict == NULL) {
return NULL;
@@ -7775,6 +7797,12 @@ PyInit__testcapi(void)
}
PyModule_AddObject(m, "HeapCTypeWithBuffer", HeapCTypeWithBuffer);
+ PyObject *HeapCTypeWithWeakref2 = PyType_FromSpec(&HeapCTypeWithWeakref2_spec);
+ if (HeapCTypeWithWeakref2 == NULL) {
+ return -1;
+ }
+ PyModule_AddObject(m, "HeapCTypeWithWeakref2", HeapCTypeWithWeakref2);
+
PyObject *HeapCTypeSetattr = PyType_FromSpec(&HeapCTypeSetattr_spec);
if (HeapCTypeSetattr == NULL) {
return NULL;
diff --git a/Objects/typeobject.c b/Objects/typeobject.c
index c5e832df7af2..03cc72e742b2 100644
--- a/Objects/typeobject.c
+++ b/Objects/typeobject.c
@@ -2224,6 +2224,11 @@ best_base(PyObject *bases)
return base;
}
+#define ADDED_FIELD_AT_OFFSET(name, offset) \
+ (type->tp_ ## name && (base->tp_ ##name == 0) && \
+ type->tp_ ## name + sizeof(PyObject *) == (offset) && \
+ type->tp_flags & Py_TPFLAGS_HEAPTYPE)
+
static int
extra_ivars(PyTypeObject *type, PyTypeObject *base)
{
@@ -2236,10 +2241,18 @@ extra_ivars(PyTypeObject *type, PyTypeObject *base)
return t_size != b_size ||
type->tp_itemsize != base->tp_itemsize;
}
- if (type->tp_weaklistoffset && base->tp_weaklistoffset == 0 &&
- type->tp_weaklistoffset + sizeof(PyObject *) == t_size &&
- type->tp_flags & Py_TPFLAGS_HEAPTYPE)
+ /* Check for __dict__ and __weakrefs__ slots in either order */
+ if (ADDED_FIELD_AT_OFFSET(weaklistoffset, t_size)) {
+ t_size -= sizeof(PyObject *);
+ }
+ if ((type->tp_flags & Py_TPFLAGS_MANAGED_DICT) == 0 &&
+ ADDED_FIELD_AT_OFFSET(dictoffset, t_size)) {
t_size -= sizeof(PyObject *);
+ }
+ /* Check __weakrefs__ again, in case it precedes __dict__ */
+ if (ADDED_FIELD_AT_OFFSET(weaklistoffset, t_size)) {
+ t_size -= sizeof(PyObject *);
+ }
return t_size != b_size;
}
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