SERVER-12977 disallow empty write batches

Also fix shell batch processing to avoid extra empty batches.

1 files changed, 8 insertions, 1 deletions

diff --git a/src/mongo/s/cluster_write.cpp b/src/mongo/s/cluster_write.cpp
index 5a8e690d61e..8b2008f02b8 100644
--- a/src/mongo/s/cluster_write.cpp
+++ b/src/mongo/s/cluster_write.cpp
@@ -333,8 +333,15 @@ namespace mongo {
             return;
         }
 
+        if ( request.sizeWriteOps() == 0u ) {
+            toBatchError( Status( ErrorCodes::InvalidLength,
+                                  "no write ops were included in the batch" ),
+                          response );
+            return;
+        }
+
         if ( request.sizeWriteOps() > BatchedCommandRequest::kMaxWriteBatchSize ) {
-            toBatchError( Status( ErrorCodes::FailedToParse,
+            toBatchError( Status( ErrorCodes::InvalidLength,
                                   str::stream() << "exceeded maximum write batch size of "
                                                 << BatchedCommandRequest::kMaxWriteBatchSize ),
                           response );