JAVA-1161: When a replica set member returns an empty list of hosts, assume it's not a part of an initiated replica set and do not remove every server from the client view of the replica set.

Author: jyemin

src/main/com/mongodb/MultiServerCluster.java

@@ -152,6 +152,11 @@ private void handleReplicaSetMemberChanged(final ServerDescription newDescriptio
             return;
         }
 
+        if (newDescription.getHosts().isEmpty()) {
+            LOGGER.info(format("Server %s does not appear to be a member of an initiated replica set.", newDescription.getAddress()));
+            return;
+        }
+
         if (replicaSetName == null) {
             replicaSetName = newDescription.getSetName();
         }

src/test/com/mongodb/MultiServerClusterSpecification.groovy

@@ -14,10 +14,6 @@
  * limitations under the License.
  */
 
-
-
-
-
 package com.mongodb
 
 import spock.lang.Specification
@@ -27,6 +23,7 @@ import static com.mongodb.ClusterType.ReplicaSet
 import static com.mongodb.ClusterType.Sharded
 import static com.mongodb.ServerConnectionState.Connected
 import static com.mongodb.ServerConnectionState.Connecting
+import static com.mongodb.ServerType.ReplicaSetOther
 import static com.mongodb.ServerType.ReplicaSetPrimary
 import static com.mongodb.ServerType.ReplicaSetSecondary
 import static com.mongodb.ServerType.ShardRouter
@@ -116,6 +113,20 @@ class MultiServerClusterSpecification extends Specification {
         }
     }
 
+    def 'should ignore an empty list of hosts when type is replica set'() {
+        given:
+        def cluster = new MultiServerCluster(
+                CLUSTER_ID, ClusterSettings.builder().requiredClusterType(ReplicaSet).hosts([firstServer, secondServer]).build(), factory,
+                CLUSTER_LISTENER)
+
+        when:
+        sendNotification(secondServer, ReplicaSetOther, [], null)  // null replica set name
+
+        then:
+        getClusterDescription(cluster).type == ReplicaSet
+        getClusterDescription(cluster).all == getServerDescriptions(firstServer, secondServer)
+    }
+
     def 'should remove a server of the wrong type when type is sharded'() {
         given:
         def cluster = new MultiServerCluster(