fix(python): check each parameter in native callback validation loop

python/_jsonnet.c

@@ -411,7 +411,7 @@ static int handle_native_callbacks(struct JsonnetVm *vm, PyObject *native_callba
         /* Check the params are all strings */
         num_params = PyTuple_Size(params);
         for (i = 0; i < num_params ; ++i) {
-            PyObject *param = PyTuple_GetItem(params, 0);
+            PyObject *param = PyTuple_GetItem(params, i);
             if (!PyUnicode_Check(param)) {
                 PyErr_SetString(PyExc_TypeError, "native callback param must be string");
                 goto bad;

python/_jsonnet_test.py

@@ -177,7 +177,17 @@ def test_double_import(self):
             import_callback=import_callback_encode,
             native_callbacks=native_callbacks,
         )
-        self.assertEqual(json_str, "84\n")
+    def test_native_callback_param_type_validation(self):
+        def dummy_cb(*args):
+            return None
+
+        # Verify that non-string parameters beyond the first index are rejected with TypeError
+        with self.assertRaises(TypeError):
+            _jsonnet.evaluate_snippet(
+                self.test_filename,
+                "null",
+                native_callbacks={"invalid_param": (("valid", 123), dummy_cb)},
+            )
 
 if __name__ == '__main__':
     unittest.main()