Two nodes compete for mining, block not synchronization.

[orchome]

evn:

1. The first node starts , org.ethereum.samples.PrivateMinerSample.MinerNode, Related configuration

 private final String config =
                // no need for discovery in that small network
                "peer.discovery.enabled = false \n" +
                "peer.discovery.bind.ip = 127.0.0.1 \n" +
                "peer.listen.port = 30335 \n" +
                 // need to have different nodeId's for the peers
                "peer.privateKey = 6ef8da380c27cea8fdf7448340ea99e8e2268fc2950d79ed47cbf6f85dc977ec \n" +
                // our private net ID
                "peer.networkId = 555 \n" +
                // we have no peers to sync with
                "sync.enabled = true \n" +
                // genesis with a lower initial difficulty and some predefined known funded accounts
                "genesis = sample-genesis.json \n" +
                // two peers need to have separate database dirs
                "database.dir = sampleDB-1 \n" +
                // when more than 1 miner exist on the network extraData helps to identify the block creator
                "mine.extraDataHex = cccccccccccccccccccc \n" +
                "mine.cpuMineThreads = 1 \n" +
                "cache.flush.blocks = 1";

I only added sync.enabled = true.

2. second node,org.ethereum.samples.PrivateMinerSample.RegularConfig

   private final String config =
               // no discovery: we are connecting directly to the miner peer
               "peer.discovery.enabled = false \n" +
               "peer.listen.port = 30336 \n" +
               "peer.privateKey = 3ec771c31cac8c0dba77a69e503765701d3c2bb62435888d4ffa38fed60c445c \n" +
               "peer.networkId = 555 \n" +
               // actively connecting to the miner
               "peer.active = [" +
               "    { url = 'enode://26ba1aadaf59d7607ad7f437146927d79e80312f026cfa635c6b2ccf2c5d3521f5812ca2beb3b295b14f97110e6448c1c7ff68f14c5328d43a3c62b44143e9b1@localhost:30335' }" +
               "] \n" +
               "sync.enabled = true \n" +
               // all peers in the same network need to use the same genesis block
               "genesis = sample-genesis.json \n" +
               // two peers need to have separate database dirs
               "database.dir = sampleDB-2 \n";

   I added a new step and started the miner when the sync is complete.

Go back to the first node.

When the second node computes a new block and broadcasts it, I will track the processNewBlock((NewBlockMessage)msg) method in Eth62 on the first node.

Found the following:

The header map in SyncQueueImpl class does not contain the value of the parent。

I think the problem is the headerRetrieveLoop method in org.ethereum.sync.BlockDownloader.

Please take a look at this problem,Thanks~!