Fixed - update new master record in DNS monitor only if it replaced old master successfully. #3104

redisson/src/main/java/org/redisson/connection/DNSMonitor.java

@@ -127,8 +127,13 @@ public class DNSMonitor {
                             log.error("Unable to find entry for current master {}", currentMasterAddr);
                             return;
                         }
-                        masterSlaveEntry.changeMaster(newMasterAddr, entry.getKey());
-                        masters.put(entry.getKey(), newMasterAddr);
+
+                        RFuture<RedisClient> changeFuture = masterSlaveEntry.changeMaster(newMasterAddr, entry.getKey());
+                        changeFuture.onComplete((r, e) -> {
+                            if (e == null) {
+                                masters.put(entry.getKey(), newMasterAddr);
+                            }
+                        });
                     }
                 }
             });

redisson/src/main/java/org/redisson/connection/MasterSlaveEntry.java

@@ -426,10 +426,11 @@ public class MasterSlaveEntry {
         return future;
     }
     
-    public void changeMaster(InetSocketAddress address, RedisURI uri) {
+    public RFuture<RedisClient> changeMaster(InetSocketAddress address, RedisURI uri) {
         ClientConnectionsEntry oldMaster = masterEntry;
         RFuture<RedisClient> future = setupMasterEntry(address, uri);
         changeMaster(uri, oldMaster, future);
+        return future;
     }