Fix compiler warnings.

PiperOrigin-RevId: 447744251
diff --git a/python/message.c b/python/message.c
index b4d2602..5b6bddd 100644
--- a/python/message.c
+++ b/python/message.c
@@ -428,8 +428,8 @@
   }
   bool ok = false;
   PyObject* repeated = PyUpb_CMessage_GetFieldValue(_self, field);
-  if (!repeated) goto err;
   PyObject* tmp = NULL;
+  if (!repeated) goto err;
   if (upb_FieldDef_IsSubMessage(field)) {
     if (!PyUpb_CMessage_InitRepeatedMessageAttribute(_self, repeated, value,
                                                      field)) {
@@ -1239,6 +1239,7 @@
 
   if (subobj_map) {
     upb_Message* msg = PyUpb_CMessage_GetMsg(self);
+    (void)msg;  // Suppress unused warning when asserts are disabled.
     intptr_t iter = PYUPB_WEAKMAP_BEGIN;
     const void* key;
     PyObject* obj;