[Python-checkins] bpo-44263: Py_TPFLAGS_HAVE_GC requires tp_traverse (GH-26463)
vstinner
webhook-mailer at python.org
Tue Jun 1 17:37:18 EDT 2021
https://github.com/python/cpython/commit/ee7637596d8de25f54261bbeabc602d31e74f482
commit: ee7637596d8de25f54261bbeabc602d31e74f482
branch: main
author: Victor Stinner <vstinner at python.org>
committer: vstinner <vstinner at python.org>
date: 2021-06-01T23:37:12+02:00
summary:
bpo-44263: Py_TPFLAGS_HAVE_GC requires tp_traverse (GH-26463)
The PyType_Ready() function now raises an error if a type is defined
with the Py_TPFLAGS_HAVE_GC flag set but has no traverse function
(PyTypeObject.tp_traverse).
files:
A Misc/NEWS.d/next/C API/2021-05-31-11-31-13.bpo-44263.8mIOfV.rst
M Doc/whatsnew/3.11.rst
M Objects/typeobject.c
diff --git a/Doc/whatsnew/3.11.rst b/Doc/whatsnew/3.11.rst
index a178095be0d0d..1b3b8240a521f 100644
--- a/Doc/whatsnew/3.11.rst
+++ b/Doc/whatsnew/3.11.rst
@@ -144,6 +144,11 @@ New Features
Porting to Python 3.11
----------------------
+* The :c:func:`PyType_Ready` function now raises an error if a type is defined
+ with the :const:`Py_TPFLAGS_HAVE_GC` flag set but has no traverse function
+ (:c:member:`PyTypeObject.tp_traverse`).
+ (Contributed by Victor Stinner in :issue:`44263`.)
+
Deprecated
----------
@@ -180,4 +185,4 @@ Removed
parameter of functions :func:`~gettext.translation` and
:func:`~gettext.install` are also removed, since they are only used for
the ``l*gettext()`` functions.
- (Contributed by Dong-hee Na and Serhiy Storchaka in :issue:`44235`.)
\ No newline at end of file
+ (Contributed by Dong-hee Na and Serhiy Storchaka in :issue:`44235`.)
diff --git a/Misc/NEWS.d/next/C API/2021-05-31-11-31-13.bpo-44263.8mIOfV.rst b/Misc/NEWS.d/next/C API/2021-05-31-11-31-13.bpo-44263.8mIOfV.rst
new file mode 100644
index 0000000000000..aa831a2083c48
--- /dev/null
+++ b/Misc/NEWS.d/next/C API/2021-05-31-11-31-13.bpo-44263.8mIOfV.rst
@@ -0,0 +1,4 @@
+The :c:func:`PyType_Ready` function now raises an error if a type is defined
+with the :const:`Py_TPFLAGS_HAVE_GC` flag set but has no traverse function
+(:c:member:`PyTypeObject.tp_traverse`).
+Patch by Victor Stinner.
diff --git a/Objects/typeobject.c b/Objects/typeobject.c
index feb25aa0b78e4..bf792e21c162d 100644
--- a/Objects/typeobject.c
+++ b/Objects/typeobject.c
@@ -158,6 +158,12 @@ _PyType_CheckConsistency(PyTypeObject *type)
CHECK(!(type->tp_flags & Py_TPFLAGS_READYING));
CHECK(type->tp_dict != NULL);
+ if (type->tp_flags & Py_TPFLAGS_HAVE_GC) {
+ // bpo-44263: tp_traverse is required if Py_TPFLAGS_HAVE_GC is set.
+ // Note: tp_clear is optional.
+ CHECK(type->tp_traverse != NULL);
+ }
+
if (type->tp_flags & Py_TPFLAGS_DISALLOW_INSTANTIATION) {
CHECK(type->tp_new == NULL);
CHECK(_PyDict_ContainsId(type->tp_dict, &PyId___new__) == 0);
@@ -3607,6 +3613,7 @@ PyType_FromModuleAndSpec(PyObject *module, PyType_Spec *spec, PyObject *bases)
}
}
+ assert(_PyType_CheckConsistency(type));
return (PyObject*)res;
fail:
@@ -5944,7 +5951,7 @@ static int add_tp_new_wrapper(PyTypeObject *type);
#define COLLECTION_FLAGS (Py_TPFLAGS_SEQUENCE | Py_TPFLAGS_MAPPING)
static int
-type_ready_checks(PyTypeObject *type)
+type_ready_pre_checks(PyTypeObject *type)
{
/* Consistency checks for PEP 590:
* - Py_TPFLAGS_METHOD_DESCRIPTOR requires tp_descr_get
@@ -6305,10 +6312,28 @@ type_ready_set_new(PyTypeObject *type)
}
+static int
+type_ready_post_checks(PyTypeObject *type)
+{
+ // bpo-44263: tp_traverse is required if Py_TPFLAGS_HAVE_GC is set.
+ // Note: tp_clear is optional.
+ if (type->tp_flags & Py_TPFLAGS_HAVE_GC
+ && type->tp_traverse == NULL)
+ {
+ PyErr_Format(PyExc_SystemError,
+ "type %s has the Py_TPFLAGS_HAVE_GC flag "
+ "but has no traverse function",
+ type->tp_name);
+ return -1;
+ }
+ return 0;
+}
+
+
static int
type_ready(PyTypeObject *type)
{
- if (type_ready_checks(type) < 0) {
+ if (type_ready_pre_checks(type) < 0) {
return -1;
}
@@ -6346,6 +6371,9 @@ type_ready(PyTypeObject *type)
if (type_ready_add_subclasses(type) < 0) {
return -1;
}
+ if (type_ready_post_checks(type) < 0) {
+ return -1;
+ }
return 0;
}
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