SERVER-21452 hearbeat response from secondary should not schedule a priority takeover

2 files changed, 12 insertions, 1 deletions

diff --git a/src/mongo/db/repl/topology_coordinator_impl.cpp b/src/mongo/db/repl/topology_coordinator_impl.cpp
index 40e36edc9ba..0808aa91153 100644
--- a/src/mongo/db/repl/topology_coordinator_impl.cpp
+++ b/src/mongo/db/repl/topology_coordinator_impl.cpp
@@ -1081,9 +1081,10 @@ HeartbeatResponseAction TopologyCoordinatorImpl::_updatePrimaryFromHBDataV1(
     // Priority takeover when the replset is stable.
     //
     // Take over the primary only if the remote primary is in the latest term I know.
+    // This is done only when we get a heartbeat response from the primary.
     // Otherwise, there must be an outstanding election, which may succeed or not, but
     // the remote primary will become aware of that election eventually and step down.
-    if (_hbdata[primaryIndex].getTerm() == _term &&
+    if (_hbdata[primaryIndex].getTerm() == _term && updatedConfigIndex == primaryIndex &&
         _rsConfig.getMemberAt(primaryIndex).getPriority() <
             _rsConfig.getMemberAt(_selfIndex).getPriority()) {
         LOG(4) << "I can take over the primary due to higher priority."
diff --git a/src/mongo/db/repl/topology_coordinator_impl_v1_test.cpp b/src/mongo/db/repl/topology_coordinator_impl_v1_test.cpp
index 32e258ee2b0..10dcad1ad5f 100644
--- a/src/mongo/db/repl/topology_coordinator_impl_v1_test.cpp
+++ b/src/mongo/db/repl/topology_coordinator_impl_v1_test.cpp
@@ -2757,6 +2757,16 @@ TEST_F(HeartbeatResponseTestV1, UpdateHeartbeatDataTermPreventsPriorityTakeover)
     ASSERT_EQUALS(HeartbeatResponseAction::PriorityTakeover, nextAction.getAction());
     ASSERT_EQUALS(2, getCurrentPrimaryIndex());
 
+    // Heartbeat from a secondary node shouldn't schedule a priority takeover.
+    nextAction = receiveUpHeartbeat(HostAndPort("host1"),
+                                    "rs0",
+                                    MemberState::RS_SECONDARY,
+                                    election,
+                                    election,
+                                    lastOpTimeApplied);
+    ASSERT_NO_ACTION(nextAction.getAction());
+    ASSERT_EQUALS(2, getCurrentPrimaryIndex());
+
     now()++;
     // Host 1 starts an election due to higher priority by sending vote requests.
     // Vote request updates my term.