Test undecodable name

Author: vstinner

Lib/test/test_capi/test_object.py

@@ -266,6 +266,13 @@ class Obj:
         self.assertIsNone(cm.exception.__cause__)
         self.assertHasAttr(obj, 'attr')
 
+        with self.assertRaises(SystemError) as cm:
+            # undecodable name
+            _testcapi.object_setattrstring_null_exc(obj, b'\xff', exc)
+        self.assertIs(cm.exception.__context__, exc)
+        self.assertIsNone(cm.exception.__cause__)
+        self.assertHasAttr(obj, 'attr')
+
 
 if __name__ == "__main__":
     unittest.main()

Modules/_testcapi/abstract.c

@@ -200,7 +200,8 @@ object_setattrstring_null_exc(PyObject *self, PyObject *args)
 {
     PyObject *obj, *exc;
     const char *name;
-    if (!PyArg_ParseTuple(args, "OsO", &obj, &name, &exc)) {
+    Py_ssize_t size;
+    if (!PyArg_ParseTuple(args, "Oz#O", &obj, &name, &size, &exc)) {
         return NULL;
     }