Merge pull request #3958 from wubin01/opt_syncblock_message_process

Modify process SyncBlockChain  message

Author: lvs007

framework/src/main/java/org/tron/core/net/messagehandler/SyncBlockChainMsgHandler.java

@@ -15,6 +15,7 @@
 import org.tron.core.net.message.SyncBlockChainMessage;
 import org.tron.core.net.message.TronMessage;
 import org.tron.core.net.peer.PeerConnection;
+import org.tron.protos.Protocol;
 
 @Slf4j(topic = "net")
 @Component
@@ -36,7 +37,11 @@ public void processMessage(PeerConnection peer, TronMessage msg) throws P2pExcep
 
     LinkedList<BlockId> blockIds = getLostBlockIds(summaryChainIds);
 
-    if (blockIds.size() == 1) {
+    if (blockIds.size() == 0) {
+      logger.error("Can't get lost block Ids.");
+      peer.disconnect(Protocol.ReasonCode.INCOMPATIBLE_CHAIN);
+      return;
+    } else if (blockIds.size() == 1) {
       peer.setNeedSyncFromUs(false);
     } else {
       peer.setNeedSyncFromUs(true);