1 files changed, 23 insertions, 7 deletions

diff --git a/src/mongo/db/repl/is_master_response.cpp b/src/mongo/db/repl/is_master_response.cpp
index 5d377768cc6..96f7f465d9a 100644
--- a/src/mongo/db/repl/is_master_response.cpp
+++ b/src/mongo/db/repl/is_master_response.cpp
@@ -65,6 +65,8 @@ const std::string kLastWriteDateFieldName = "lastWriteDate";
 const std::string kLastMajorityWriteOpTimeFieldName = "majorityOpTime";
 const std::string kLastMajorityWriteDateFieldName = "majorityWriteDate";
 const std::string kLastWriteFieldName = "lastWrite";
+const std::string kIsWritablePrimaryFieldName = "isWritablePrimary";
+const std::string kSecondaryDelaySecsFieldName = "secondaryDelaySecs";
 
 // field name constants that don't directly correspond to member variables
 const std::string kInfoFieldName = "info";
@@ -102,7 +104,7 @@ IsMasterResponse::IsMasterResponse()
       _configSet(true),
       _shutdownInProgress(false) {}
 
-void IsMasterResponse::addToBSON(BSONObjBuilder* builder) const {
+void IsMasterResponse::addToBSON(BSONObjBuilder* builder, bool useLegacyResponseFields) const {
     if (_topologyVersion) {
         BSONObjBuilder topologyVersionBuilder(builder->subobjStart(kTopologyVersionFieldName));
         _topologyVersion->serialize(&topologyVersionBuilder);
@@ -141,7 +143,11 @@ void IsMasterResponse::addToBSON(BSONObjBuilder* builder) const {
     }
 
     if (!_configSet) {
-        builder->append(kIsMasterFieldName, false);
+        if (useLegacyResponseFields) {
+            builder->append(kIsMasterFieldName, false);
+        } else {
+            builder->append(kIsWritablePrimaryFieldName, false);
+        }
         builder->append(kSecondaryFieldName, false);
         builder->append(kInfoFieldName, "Does not have a valid replica set config");
         builder->append(kIsReplicaSetFieldName, true);
@@ -151,7 +157,11 @@ void IsMasterResponse::addToBSON(BSONObjBuilder* builder) const {
     invariant(_setVersionSet);
     builder->append(kSetVersionFieldName, static_cast<int>(_setVersion));
     invariant(_isMasterSet);
-    builder->append(kIsMasterFieldName, _isMaster);
+    if (useLegacyResponseFields) {
+        builder->append(kIsMasterFieldName, _isMaster);
+    } else {
+        builder->append(kIsWritablePrimaryFieldName, _isMaster);
+    }
     invariant(_isSecondarySet);
     builder->append(kSecondaryFieldName, _secondary);
 
@@ -165,8 +175,14 @@ void IsMasterResponse::addToBSON(BSONObjBuilder* builder) const {
         builder->append(kHiddenFieldName, _hidden);
     if (_buildIndexesSet)
         builder->append(kBuildIndexesFieldName, _buildIndexes);
-    if (_slaveDelaySet)
-        builder->appendIntOrLL(kSlaveDelayFieldName, durationCount<Seconds>(_slaveDelay));
+    if (_slaveDelaySet) {
+        if (useLegacyResponseFields) {
+            builder->appendIntOrLL(kSlaveDelayFieldName, durationCount<Seconds>(_slaveDelay));
+        } else {
+            builder->appendIntOrLL(kSecondaryDelaySecsFieldName,
+                                   durationCount<Seconds>(_slaveDelay));
+        }
+    }
     if (_tagsSet) {
         BSONObjBuilder tags(builder->subobjStart(kTagsFieldName));
         for (stdx::unordered_map<std::string, std::string>::const_iterator it = _tags.begin();
@@ -193,9 +209,9 @@ void IsMasterResponse::addToBSON(BSONObjBuilder* builder) const {
     }
 }
 
-BSONObj IsMasterResponse::toBSON() const {
+BSONObj IsMasterResponse::toBSON(bool useLegacyResponseFields) const {
     BSONObjBuilder builder;
-    addToBSON(&builder);
+    addToBSON(&builder, useLegacyResponseFields);
     return builder.obj();
 }