SERVER-114927 Fix overflow (#44974)

GitOrigin-RevId: 2dda5a7d3ce9b689495c473e01c91417afc404d4

src/mongo/db/commands/query_cmd/getmore_cmd.cpp

@@ -488,7 +488,8 @@ public:
             // We intentionally set the batch size to the max size_t value for a batch size of 0 in
             // order to simulate "no limit" on the batch size. We will run out of space in the
             // buffer before we reach this limit anyway.
-            size_t batchSize = cmd.getBatchSize().value_or(std::numeric_limits<size_t>::max());
+            size_t batchSize = cmd.getBatchSize() ? static_cast<size_t>(*cmd.getBatchSize())
+                                                  : std::numeric_limits<size_t>::max();
 
             try {
                 return batchedExecute(