Fix 1244 Mempool.ReverifyTransactions (neo-project#1248)

* add internal to DB and WriteBatch

* reset db.cs writebatch.cs

* fix Nep5Token.Burn method

* format

* format

* reset and fix memorypool.ReverifyTransactions

* reset and fix ReverifyTransactions

* add ut

* remove commit

* fix BlockPersistAndReverificationWillAbandonTxAsBalanceTransfered.balance

* update comments

neo.UnitTests/Ledger/UT_MemoryPool.cs

@@ -8,6 +8,7 @@
 using Neo.Network.P2P.Payloads;
 using Neo.Persistence;
 using Neo.Plugins;
+using Neo.SmartContract;
 using Neo.SmartContract.Native;
 using System;
 using System.Collections;
@@ -92,6 +93,31 @@ private Transaction CreateTransactionWithFee(long fee)
  return mock.Object;
  }
 
+ private Transaction CreateTransactionWithFeeAndBalanceVerify(long fee)
+ {
+ Random random = new Random();
+ var randomBytes = new byte[16];
+ random.NextBytes(randomBytes);
+ Mock<Transaction> mock = new Mock<Transaction>();
+ UInt160 sender = UInt160.Zero;
+ mock.Setup(p => p.Reverify(It.IsAny<Snapshot>(), It.IsAny<BigInteger>())).Returns(((Snapshot snapshot, BigInteger amount) => NativeContract.GAS.BalanceOf(snapshot, sender) >= amount + fee));
+ mock.Setup(p => p.Verify(It.IsAny<Snapshot>(), It.IsAny<BigInteger>())).Returns(true);
+ mock.Object.Script = randomBytes;
+ mock.Object.Sender = sender;
+ mock.Object.NetworkFee = fee;
+ mock.Object.Attributes = new TransactionAttribute[0];
+ mock.Object.Cosigners = new Cosigner[0];
+ mock.Object.Witnesses = new[]
+ {
+ new Witness
+ {
+ InvocationScript = new byte[0],
+ VerificationScript = new byte[0]
+ }
+ };
+ return mock.Object;
+ }
+
  private Transaction CreateTransaction(long fee = -1)
  {
  if (fee != -1)
@@ -115,6 +141,17 @@ private void AddTransaction(Transaction txToAdd)
  _unit.TryAdd(txToAdd.Hash, txToAdd);
  }
 
+ private void AddTransactionsWithBalanceVerify(int count, long fee)
+ {
+ for (int i = 0; i < count; i++)
+ {
+ var txToAdd = CreateTransactionWithFeeAndBalanceVerify(fee);
+ _unit.TryAdd(txToAdd.Hash, txToAdd);
+ }
+
+ Console.WriteLine($"created {count} tx");
+ }
+
  [TestMethod]
  public void CapacityTest()
  {
@@ -171,6 +208,38 @@ public void BlockPersistMovesTxToUnverifiedAndReverification()
  _unit.UnverifiedSortedTxCount.Should().Be(0);
  }
 
+ [TestMethod]
+ public void BlockPersistAndReverificationWillAbandonTxAsBalanceTransfered()
+ {
+ long txFee = 1;
+ AddTransactionsWithBalanceVerify(70, txFee);
+
+ _unit.SortedTxCount.Should().Be(70);
+
+ var block = new Block
+ {
+ Transactions = _unit.GetSortedVerifiedTransactions().Take(10).ToArray()
+ };
+
+ // Simulate the transfer process in tx by burning the balance
+ UInt160 sender = block.Transactions[0].Sender;
+ Snapshot snapshot = Blockchain.Singleton.GetSnapshot();
+ BigInteger balance = NativeContract.GAS.BalanceOf(snapshot, sender);
+
+ ApplicationEngine applicationEngine = new ApplicationEngine(TriggerType.All, block, snapshot, (long)balance);
+ NativeContract.GAS.Burn(applicationEngine, sender, balance);
+ NativeContract.GAS.Mint(applicationEngine, sender, txFee * 30); // Set the balance to meet 30 txs only
+
+ // Persist block and reverify all the txs in mempool, but half of the txs will be discarded
+ _unit.UpdatePoolForBlockPersisted(block, snapshot);
+ _unit.SortedTxCount.Should().Be(30);
+ _unit.UnverifiedSortedTxCount.Should().Be(0);
+
+ // Revert the balance
+ NativeContract.GAS.Burn(applicationEngine, sender, txFee * 30);
+ NativeContract.GAS.Mint(applicationEngine, sender, balance);
+ }
+
  private void VerifyTransactionsSortedDescending(IEnumerable<Transaction> transactions)
  {
  Transaction lastTransaction = null;

neo/Ledger/MemoryPool.cs

@@ -417,7 +417,10 @@ private int ReverifyTransactions(SortedSet<PoolItem> verifiedSortedTxPool,
  foreach (PoolItem item in unverifiedSortedTxPool.Reverse().Take(count))
  {
  if (item.Tx.Reverify(snapshot, SendersFeeMonitor.GetSenderFee(item.Tx.Sender)))
+ {
  reverifiedItems.Add(item);
+ SendersFeeMonitor.AddSenderFee(item.Tx);
+ }
  else // Transaction no longer valid -- it will be removed from unverifiedTxPool.
  invalidItems.Add(item);
 
@@ -438,7 +441,6 @@ private int ReverifyTransactions(SortedSet<PoolItem> verifiedSortedTxPool,
  {
  if (_unsortedTransactions.TryAdd(item.Tx.Hash, item))
  {
- SendersFeeMonitor.AddSenderFee(item.Tx);
  verifiedSortedTxPool.Add(item);
 
  if (item.LastBroadcastTimestamp < rebroadcastCutOffTime)
@@ -447,6 +449,8 @@ private int ReverifyTransactions(SortedSet<PoolItem> verifiedSortedTxPool,
  item.LastBroadcastTimestamp = DateTime.UtcNow;
  }
  }
+ else
+ SendersFeeMonitor.RemoveSenderFee(item.Tx);
 
  _unverifiedTransactions.Remove(item.Tx.Hash);
  unverifiedSortedTxPool.Remove(item);