SERVER-18094 Add 'localOps' parameter to $currentOp to show local mongoS operations

2 files changed, 21 insertions, 2 deletions

diff --git a/src/mongo/rpc/metadata/client_metadata.cpp b/src/mongo/rpc/metadata/client_metadata.cpp
index adcb3711b71..eebf1b6d9dc 100644
--- a/src/mongo/rpc/metadata/client_metadata.cpp
+++ b/src/mongo/rpc/metadata/client_metadata.cpp
@@ -306,9 +306,26 @@ void ClientMetadata::setMongoSMetadata(StringData hostAndPort,
         sub.append(kVersion, version);
     }
 
-    _document = builder.obj();
-}
+    auto document = builder.obj();
+
+    if (!_appName.empty()) {
+        // The _appName field points into the existing _document, which we are about to replace.
+        // We must redirect _appName to point into the new doc *before* replacing the old doc. We
+        // expect the 'application' metadata of the new document to be identical to the old.
+        auto appMetaData = document[kApplication];
+        invariant(appMetaData.isABSONObj());
+
+        auto appNameEl = appMetaData[kName];
+        invariant(appNameEl.type() == BSONType::String);
+
+        auto appName = appNameEl.valueStringData();
+        invariant(appName == _appName);
 
+        _appName = appName;
+    }
+
+    _document = std::move(document);
+}
 
 void ClientMetadata::serialize(StringData driverName,
                                StringData driverVersion,
diff --git a/src/mongo/rpc/metadata/client_metadata_test.cpp b/src/mongo/rpc/metadata/client_metadata_test.cpp
index 7d3166127f4..30e96b33bf8 100644
--- a/src/mongo/rpc/metadata/client_metadata_test.cpp
+++ b/src/mongo/rpc/metadata/client_metadata_test.cpp
@@ -313,6 +313,8 @@ TEST(ClientMetadatTest, TestMongoSAppend) {
     ASSERT_EQUALS("g", swParseStatus.getValue().get().getApplicationName());
 
     swParseStatus.getValue().get().setMongoSMetadata("h", "i", "j");
+    ASSERT_EQUALS("g", swParseStatus.getValue().get().getApplicationName());
+
     auto doc = swParseStatus.getValue().get().getDocument();
 
     constexpr auto kMongos = "mongos"_sd;