Fixed error message when serializing with required fields missing.
diff --git a/python/message.c b/python/message.c
index 45c70e9..0b501fc 100644
--- a/python/message.c
+++ b/python/message.c
@@ -1328,6 +1328,18 @@
if (!pb) {
PyUpb_ModuleState* state = PyUpb_ModuleState_Get();
+ PyObject* errors = PyUpb_CMessage_FindInitializationErrors(_self, NULL);
+ if (PyList_Size(errors) != 0) {
+ PyObject* comma = PyUnicode_FromString(",");
+ PyObject* missing_fields = PyUnicode_Join(comma, errors);
+ PyErr_Format(state->encode_error_class,
+ "Message %s is missing required fields: %U",
+ upb_msgdef_fullname(msgdef), missing_fields);
+ Py_XDECREF(comma);
+ Py_XDECREF(missing_fields);
+ Py_DECREF(errors);
+ goto done;
+ }
PyErr_Format(state->encode_error_class, "Failed to serialize proto");
goto done;
}
