Jun 25, 2022 · Jun 24, 2022 · Jun 24, 2022 · Jun 24, 2022
diff --git a/Lib/test/test_struct.py b/Lib/test/test_struct.py
 from collections import abc
 import array
 import gc
 import math
 import operator
 import unittest
 import struct
 import sys
 import weakref

 from test import support
 from test.support import import_helper
        self.assertIn(b"Exception ignored in:", stderr)
        self.assertIn(b"C.__del__", stderr)

    def test__struct_reference_cycle_cleaned_up(self):
        # Regression test for python/cpython#94207.

        # When we create a new struct module, trigger use of its cache,
        # and then delete it ...
        _struct_module = import_helper.import_fresh_module("_struct")
        module_ref = weakref.ref(_struct_module)
        _struct_module.calcsize("b")
        del _struct_module

        # Then the module should have been garbage collected.
        gc.collect()
        self.assertIsNone(
            module_ref(), "_struct module was not garbage collected")

    def test_issue35714(self):
        # Embedded null characters should not be allowed in format strings.
        for s in '\0', '2\0i', b'\0':
diff --git a/Misc/NEWS.d/next/Library/2022-06-24-19-23-59.gh-issue-94207.VhS1eS.rst b/Misc/NEWS.d/next/Library/2022-06-24-19-23-59.gh-issue-94207.VhS1eS.rst
 Made :class:`_struct.Struct` GC-tracked in order to fix a reference leak in
 the :mod:`_struct` module.
diff --git a/Modules/_struct.c b/Modules/_struct.c
    return ret;
 }

 static int
 s_clear(PyStructObject *s)
 {
    Py_CLEAR(s->s_format);
    return 0;
 }

 static int
 s_traverse(PyStructObject *s, visitproc visit, void *arg)
 {
    Py_VISIT(Py_TYPE(s));
    Py_VISIT(s->s_format);
    return 0;
 }

 static void
 s_dealloc(PyStructObject *s)
 {
    PyTypeObject *tp = Py_TYPE(s);
    PyObject_GC_UnTrack(s);
    if (s->weakreflist != NULL)
        PyObject_ClearWeakRefs((PyObject *)s);
    if (s->s_codes != NULL) {
    {Py_tp_getattro, PyObject_GenericGetAttr},
    {Py_tp_setattro, PyObject_GenericSetAttr},
    {Py_tp_doc, (void*)s__doc__},
    {Py_tp_traverse, s_traverse},
    {Py_tp_clear, s_clear},
    {Py_tp_methods, s_methods},
    {Py_tp_members, s_members},
    {Py_tp_getset, s_getsetlist},
    {Py_tp_init, Struct___init__},
    {Py_tp_alloc, PyType_GenericAlloc},
    {Py_tp_new, s_new},
    {Py_tp_free,PyObject_Del},
    {Py_tp_free,PyObject_GC_Del},
    {0, 0},
 };

 static PyType_Spec PyStructType_spec = {
    "_struct.Struct",
    sizeof(PyStructObject),
    0,
    Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE,
    Py_TPFLAGS_DEFAULT |Py_TPFLAGS_HAVE_GC |Py_TPFLAGS_BASETYPE,
    PyStructType_slots
 };
Original file line number	Diff line number	Diff line change
		@@ -1,10 +1,12 @@
		from collections import abc
		import array
		import gc
		import math
		import operator
		import unittest
		import struct
		import sys
		import weakref

		from test import support
		from test.support import import_helper
Expand DownExpand Up		@@ -672,6 +674,21 @@ def __del__(self):
		self.assertIn(b"Exception ignored in:", stderr)
		self.assertIn(b"C.__del__", stderr)

		def test__struct_reference_cycle_cleaned_up(self):
		# Regression test for python/cpython#94207.

		# When we create a new struct module, trigger use of its cache,
		# and then delete it ...
		_struct_module = import_helper.import_fresh_module("_struct")
		module_ref = weakref.ref(_struct_module)
		_struct_module.calcsize("b")
		del _struct_module

		# Then the module should have been garbage collected.
		gc.collect()
		self.assertIsNone(
		module_ref(), "_struct module was not garbage collected")

		def test_issue35714(self):
		# Embedded null characters should not be allowed in format strings.
		for s in '\0', '2\0i', b'\0':
Expand Down
Original file line number	Diff line number	Diff line change
		@@ -0,0 +1,2 @@
		Made :class:`_struct.Struct` GC-tracked in order to fix a reference leak in
		the :mod:`_struct` module.
Original file line number	Diff line number	Diff line change
Expand Up		@@ -1496,10 +1496,26 @@ Struct___init___impl(PyStructObject self, PyObject format)
		return ret;
		}

		static int
		s_clear(PyStructObject *s)
		{
		Py_CLEAR(s->s_format);
		return 0;
		}

		static int
		s_traverse(PyStructObject s, visitproc visit, void arg)
		{
		Py_VISIT(Py_TYPE(s));
		Py_VISIT(s->s_format);
		return 0;
		}

		static void
		s_dealloc(PyStructObject *s)
		{
		PyTypeObject *tp = Py_TYPE(s);
		PyObject_GC_UnTrack(s);
		if (s->weakreflist != NULL)
		PyObject_ClearWeakRefs((PyObject *)s);
		if (s->s_codes != NULL) {
Expand DownExpand Up		@@ -2078,21 +2094,23 @@ static PyType_Slot PyStructType_slots[] = {
		{Py_tp_getattro, PyObject_GenericGetAttr},
		{Py_tp_setattro, PyObject_GenericSetAttr},
		{Py_tp_doc, (void*)s__doc__},
		{Py_tp_traverse, s_traverse},
		{Py_tp_clear, s_clear},
		{Py_tp_methods, s_methods},
		{Py_tp_members, s_members},
		{Py_tp_getset, s_getsetlist},
		{Py_tp_init, Struct___init__},
		{Py_tp_alloc, PyType_GenericAlloc},
		{Py_tp_new, s_new},
		{Py_tp_free,PyObject_Del},
		{Py_tp_free,PyObject_GC_Del},
		{0, 0},
		};

		static PyType_Spec PyStructType_spec = {
		"_struct.Struct",
		sizeof(PyStructObject),
		0,
		Py_TPFLAGS_DEFAULT \| Py_TPFLAGS_BASETYPE,
		Py_TPFLAGS_DEFAULT \|Py_TPFLAGS_HAVE_GC \|Py_TPFLAGS_BASETYPE,
		PyStructType_slots
		};

Expand Down