SERVER-20700 Sort split keys returned by splitVector

2 files changed, 20 insertions, 1 deletions

diff --git a/src/mongo/db/s/collection_metadata.cpp b/src/mongo/db/s/collection_metadata.cpp
index b8c9cfa7b7a..d0bb88be073 100644
--- a/src/mongo/db/s/collection_metadata.cpp
+++ b/src/mongo/db/s/collection_metadata.cpp
@@ -323,7 +323,21 @@ CollectionMetadata* CollectionMetadata::cloneSplit(const ChunkType& chunk,
     BSONObj startKey = chunk.getMin();
     for (vector<BSONObj>::const_iterator it = splitKeys.begin(); it != splitKeys.end(); ++it) {
         BSONObj split = *it;
-        invariant(split.woCompare(startKey) > 0);
+        if (split.woCompare(startKey) <= 0) {
+            // The split keys came in out of order, this probably indicates a bug, so fail the
+            // operation.  Re-iterate splitKeys to build a useful error message including the
+            // array of splitKeys in the order received.
+            std::stringstream ss;
+            ss << "Invalid input to splitChunk, split keys must be in order, got: [";
+            for (auto it2 = splitKeys.cbegin(); it2 != splitKeys.cend(); ++it2) {
+                if (it2 != splitKeys.begin()) {
+                    ss << ", ";
+                }
+                ss << it2->toString();
+            }
+            ss << "]";
+            uasserted(28821, ss.str());
+        }
         metadata->_chunksMap[startKey] = split.getOwned();
         metadata->_chunksMap.insert(make_pair(split.getOwned(), chunk.getMax().getOwned()));
         metadata->_shardVersion.incMinor();
diff --git a/src/mongo/s/d_split.cpp b/src/mongo/s/d_split.cpp
index 16eec736bfa..0a7c367b2ca 100644
--- a/src/mongo/s/d_split.cpp
+++ b/src/mongo/s/d_split.cpp
@@ -30,6 +30,7 @@
 
 #include "mongo/platform/basic.h"
 
+#include <algorithm>
 #include <map>
 #include <string>
 #include <vector>
@@ -508,6 +509,10 @@ public:
             result.append("timeMillis", timer.millis());
         }
 
+        // Make sure splitKeys is in ascending order
+        std::sort(splitKeys.begin(),
+                  splitKeys.end(),
+                  [](const BSONObj& lhs, const BSONObj& rhs) -> bool { return lhs < rhs; });
         result.append("splitKeys", splitKeys);
         return true;
     }