Dec 11, 2025 · Dec 11, 2025
diff --git a/Lib/test/test_capi/test_object.py b/Lib/test/test_capi/test_object.py

 func(object())

 # Test that a newly created object in C is not considered
 # a uniquely referenced temporary, because it's not on the stack.
 # gh-142586: do the test in a loop over a list to test for handling
 # tagged ints on the stack.
 foriin [0,1,2]:
 self.assertFalse(_testcapi.pyobject_is_unique_temporary_new_object())

 defpyobject_dump(self,obj,release_gil=False):
 pyobject_dump=_testcapi.pyobject_dump

diff --git a/Misc/NEWS.d/next/C_API/2025-12-11-13-01-49.gh-issue-142589.nNAqgw.rst b/Misc/NEWS.d/next/C_API/2025-12-11-13-01-49.gh-issue-142589.nNAqgw.rst
 Fix :c:func:`PyUnstable_Object_IsUniqueReferencedTemporary()` handling of
 tagged ints on the interpreter stack.
diff --git a/Modules/_testcapi/object.c b/Modules/_testcapi/object.c
    return PyLong_FromLong(result);
 }

 static PyObject *
 pyobject_is_unique_temporary_new_object(PyObject *self, PyObject *unused)
 {
    PyObject *obj = PyList_New(0);
    int result = PyUnstable_Object_IsUniqueReferencedTemporary(obj);
    Py_DECREF(obj);
    return PyLong_FromLong(result);
 }

 static int MyObject_dealloc_called = 0;

 static void
    {"pyobject_clear_weakrefs_no_callbacks", pyobject_clear_weakrefs_no_callbacks, METH_O},
    {"pyobject_enable_deferred_refcount", pyobject_enable_deferred_refcount, METH_O},
    {"pyobject_is_unique_temporary", pyobject_is_unique_temporary, METH_O},
    {"pyobject_is_unique_temporary_new_object", pyobject_is_unique_temporary_new_object, METH_NOARGS},
    {"test_py_try_inc_ref", test_py_try_inc_ref, METH_NOARGS},
    {"test_xincref_doesnt_leak",test_xincref_doesnt_leak,        METH_NOARGS},
    {"test_incref_doesnt_leak", test_incref_doesnt_leak,         METH_NOARGS},
diff --git a/Objects/object.c b/Objects/object.c
 _PyStackRef*stackpointer=frame->stackpointer;
 while (stackpointer>base) {
 stackpointer--;
 if (op==PyStackRef_AsPyObjectBorrow(*stackpointer)) {
 returnPyStackRef_IsHeapSafe(*stackpointer);
 _PyStackRefref=*stackpointer;
 if (PyStackRef_IsTaggedInt(ref)) {
 continue;
        }
 if (op==PyStackRef_AsPyObjectBorrow(ref)) {
 returnPyStackRef_IsHeapSafe(ref);
        }
    }
 return0;
Original file line number	Diff line number	Diff line change
Expand Up		@@ -251,6 +251,13 @@ def func(x):

		func(object())

		# Test that a newly created object in C is not considered
		# a uniquely referenced temporary, because it's not on the stack.
		# gh-142586: do the test in a loop over a list to test for handling
		# tagged ints on the stack.
		foriin [0,1,2]:
		self.assertFalse(_testcapi.pyobject_is_unique_temporary_new_object())

		defpyobject_dump(self,obj,release_gil=False):
		pyobject_dump=_testcapi.pyobject_dump

Expand Down
Original file line number	Diff line number	Diff line change
		@@ -0,0 +1,2 @@
		Fix :c:func:`PyUnstable_Object_IsUniqueReferencedTemporary()` handling of
		tagged ints on the interpreter stack.
Original file line number	Diff line number	Diff line change
Expand Up		@@ -138,6 +138,15 @@ pyobject_is_unique_temporary(PyObject self, PyObject obj)
		return PyLong_FromLong(result);
		}

		static PyObject *
		pyobject_is_unique_temporary_new_object(PyObject self, PyObject unused)
		{
		PyObject *obj = PyList_New(0);
		int result = PyUnstable_Object_IsUniqueReferencedTemporary(obj);
		Py_DECREF(obj);
		return PyLong_FromLong(result);
		}

		static int MyObject_dealloc_called = 0;

		static void
Expand DownExpand Up		@@ -517,6 +526,7 @@ static PyMethodDef test_methods[] = {
		{"pyobject_clear_weakrefs_no_callbacks", pyobject_clear_weakrefs_no_callbacks, METH_O},
		{"pyobject_enable_deferred_refcount", pyobject_enable_deferred_refcount, METH_O},
		{"pyobject_is_unique_temporary", pyobject_is_unique_temporary, METH_O},
		{"pyobject_is_unique_temporary_new_object", pyobject_is_unique_temporary_new_object, METH_NOARGS},
		{"test_py_try_inc_ref", test_py_try_inc_ref, METH_NOARGS},
		{"test_xincref_doesnt_leak",test_xincref_doesnt_leak, METH_NOARGS},
		{"test_incref_doesnt_leak", test_incref_doesnt_leak, METH_NOARGS},
Expand Down
Original file line number	Diff line number	Diff line change
Expand Up		@@ -2759,8 +2759,12 @@ PyUnstable_Object_IsUniqueReferencedTemporary(PyObject *op)
		_PyStackRef*stackpointer=frame->stackpointer;
		while (stackpointer>base) {
		stackpointer--;
		if (op==PyStackRef_AsPyObjectBorrow(*stackpointer)) {
		returnPyStackRef_IsHeapSafe(*stackpointer);
		_PyStackRefref=*stackpointer;
		if (PyStackRef_IsTaggedInt(ref)) {
		continue;
		}
		if (op==PyStackRef_AsPyObjectBorrow(ref)) {
		returnPyStackRef_IsHeapSafe(ref);
		}
		}
		return0;
Expand Down