Add PoC of pythonGH-99233

Lib/test/test_clinic.py

@@ -1256,6 +1256,12 @@ def test_gh_32092_oob(self):
     def test_gh_32092_kw_pass(self):
         ac_tester.gh_32092_kw_pass(1, 2, 3)
 
+    def test_gh_99233_refcount(self):
+        arg = '*A unique string is not referenced by anywhere else.*'
+        arg_refcount_origin = sys.getrefcount(arg)
+        ac_tester.gh_99233_refcount(arg)
+        arg_refcount_after = sys.getrefcount(arg)
+        self.assertEqual(arg_refcount_origin, arg_refcount_after)
 
 if __name__ == "__main__":
     unittest.main()

Modules/_testclinic.c

@@ -1029,6 +1029,29 @@ gh_32092_kw_pass_impl(PyObject *module, PyObject *pos, PyObject *args,
 }
 
 
+/*[clinic input]
+gh_99233_refcount
+
+    *args: object
+    /
+
+Proof-of-concept of GH-99233 refcount error bug.
+
+While AC-generated code is packing varargs to a tuple, the arguments' refcounts are not increased.
+So all the packed arguments‘ refcounts are decreased 1 improperly when the tuple is released later.
+
+Call this function with whatever arguments and check if the arguments' refcount is correct.
+
+[clinic start generated code]*/
+
+static PyObject *
+gh_99233_refcount_impl(PyObject *module, PyObject *args)
+/*[clinic end generated code: output=585855abfbca9a7f input=574e697575fafec5]*/
+{
+    Py_RETURN_NONE;
+}
+
+
 static PyMethodDef tester_methods[] = {
     TEST_EMPTY_FUNCTION_METHODDEF
     OBJECTS_CONVERTER_METHODDEF
@@ -1077,6 +1100,7 @@ static PyMethodDef tester_methods[] = {
     VARARG_WITH_ONLY_DEFAULTS_METHODDEF
     GH_32092_OOB_METHODDEF
     GH_32092_KW_PASS_METHODDEF
+    GH_99233_REFCOUNT_METHODDEF
     {NULL, NULL}
 };