Bug report

I don't think it is very important, since this is just a test, but why have it when it is spotted?

1. test_k_code:

   cpython/Modules/_testcapi/getargs.c

   Lines 331 to 398 in 326c6c4

   	/* This function not only tests the 'k' getargs code, but also the
   	PyLong_AsUnsignedLongMask() function. */
   	static PyObject *
   	test_k_code(PyObject *self, PyObject *Py_UNUSED(ignored))
   	{
   	PyObject *tuple, *num;
   	unsigned long value;
   	tuple = PyTuple_New(1);
   	if (tuple == NULL) {
   	return NULL;
   	}
   	/* a number larger than ULONG_MAX even on 64-bit platforms */
   	num = PyLong_FromString("FFFFFFFFFFFFFFFFFFFFFFFF", NULL, 16);
   	if (num == NULL) {
   	return NULL;
   	}
   	value = PyLong_AsUnsignedLongMask(num);
   	if (value != ULONG_MAX) {
   	PyErr_SetString(PyExc_AssertionError,
   	"test_k_code: "
   	"PyLong_AsUnsignedLongMask() returned wrong value for long 0xFFF...FFF");
   	return NULL;
   	}
   	PyTuple_SET_ITEM(tuple, 0, num);
   	value = 0;
   	if (!PyArg_ParseTuple(tuple, "k:test_k_code", &value)) {
   	return NULL;
   	}
   	if (value != ULONG_MAX) {
   	PyErr_SetString(PyExc_AssertionError,
   	"test_k_code: k code returned wrong value for long 0xFFF...FFF");
   	return NULL;
   	}
   	Py_DECREF(num);
   	num = PyLong_FromString("-FFFFFFFF000000000000000042", NULL, 16);
   	if (num == NULL) {
   	return NULL;
   	}
   	value = PyLong_AsUnsignedLongMask(num);
   	if (value != (unsigned long)-0x42) {
   	PyErr_SetString(PyExc_AssertionError,
   	"test_k_code: "
   	"PyLong_AsUnsignedLongMask() returned wrong value for long -0xFFF..000042");
   	return NULL;
   	}
   	PyTuple_SET_ITEM(tuple, 0, num);
   	value = 0;
   	if (!PyArg_ParseTuple(tuple, "k:test_k_code", &value)) {
   	return NULL;
   	}
   	if (value != (unsigned long)-0x42) {
   	PyErr_SetString(PyExc_AssertionError,
   	"test_k_code: k code returned wrong value for long -0xFFF..000042");
   	return NULL;
   	}
   	Py_DECREF(tuple);
   	Py_RETURN_NONE;
   	}

On errors tuple is not decrefed.
Also, note these lines:

Here' we leave a tuple is a semi-broken state. Its 0'th item has a reference count of 0.
We should also recreate a tuple here with the new items. test_L_code also has this problem.

2. cpython/Modules/_testcapi/getargs.c

   Lines 684 to 732 in 326c6c4

   	static PyObject *
   	test_L_code(PyObject *self, PyObject *Py_UNUSED(ignored))
   	{
   	PyObject *tuple, *num;
   	long long value;
   	tuple = PyTuple_New(1);
   	if (tuple == NULL) {
   	return NULL;
   	}
   	num = PyLong_FromLong(42);
   	if (num == NULL) {
   	return NULL;
   	}
   	PyTuple_SET_ITEM(tuple, 0, num);
   	value = -1;
   	if (!PyArg_ParseTuple(tuple, "L:test_L_code", &value)) {
   	return NULL;
   	}
   	if (value != 42) {
   	PyErr_SetString(PyExc_AssertionError,
   	"test_L_code: L code returned wrong value for long 42");
   	return NULL;
   	}
   	Py_DECREF(num);
   	num = PyLong_FromLong(42);
   	if (num == NULL) {
   	return NULL;
   	}
   	PyTuple_SET_ITEM(tuple, 0, num);
   	value = -1;
   	if (!PyArg_ParseTuple(tuple, "L:test_L_code", &value)) {
   	return NULL;
   	}
   	if (value != 42) {
   	PyErr_SetString(PyExc_AssertionError,
   	"test_L_code: L code returned wrong value for int 42");
   	return NULL;
   	}
   	Py_DECREF(tuple);
   	Py_RETURN_NONE;
   	}

On errors tuple is not decrefed. And num is re-assigned without tuple cleanup.

3. cpython/Modules/_testcapi/getargs.c

   Lines 734 to 767 in 326c6c4

   	/* Test the s and z codes for PyArg_ParseTuple.
   	*/
   	static PyObject *
   	test_s_code(PyObject *self, PyObject *Py_UNUSED(ignored))
   	{
   	/* Unicode strings should be accepted */
   	PyObject *tuple = PyTuple_New(1);
   	if (tuple == NULL) {
   	return NULL;
   	}
   	PyObject *obj = PyUnicode_Decode("t\xeate", strlen("t\xeate"),
   	"latin-1", NULL);
   	if (obj == NULL) {
   	return NULL;
   	}
   	PyTuple_SET_ITEM(tuple, 0, obj);
   	/* These two blocks used to raise a TypeError:
   	* "argument must be string without null bytes, not str"
   	*/
   	char *value;
   	if (!PyArg_ParseTuple(tuple, "s:test_s_code1", &value)) {
   	return NULL;
   	}
   	if (!PyArg_ParseTuple(tuple, "z:test_s_code2", &value)) {
   	return NULL;
   	}
   	Py_DECREF(tuple);
   	Py_RETURN_NONE;
   	}

As well, tuple is leaked on errors.

I have a PR ready.

Linked PRs

• gh-110572: Fix leaks in test_*_code in _testcapi/getargs.c #110573
• [3.12] gh-110572: Fix potential leaks in test_*_code in _testcapi/getargs.c (GH-110573) #111161
• gh-110572: Remove test_* from _testcapi/getargs.c #111214