Fix Oracle PostPersist

src/neo/Ledger/TransactionVerificationContext.cs

@@ -13,8 +13,16 @@ public class TransactionVerificationContext
  /// </summary>
  private readonly Dictionary<UInt160, BigInteger> senderFee = new Dictionary<UInt160, BigInteger>();
 
+ /// <summary>
+ /// Store oracle responses
+ /// </summary>
+ private readonly Dictionary<ulong, UInt256> oracleResponses = new Dictionary<ulong, UInt256>();
+
  public void AddTransaction(Transaction tx)
  {
+ var oracle = tx.GetAttribute<OracleResponse>();
+ if (oracle != null) oracleResponses.Add(oracle.Id, tx.Hash);
+
  if (senderFee.TryGetValue(tx.Sender, out var value))
  senderFee[tx.Sender] = value + tx.SystemFee + tx.NetworkFee;
  else
@@ -25,13 +33,23 @@ public bool CheckTransaction(Transaction tx, StoreView snapshot)
  {
  BigInteger balance = NativeContract.GAS.BalanceOf(snapshot, tx.Sender);
  senderFee.TryGetValue(tx.Sender, out var totalSenderFeeFromPool);
+
  BigInteger fee = tx.SystemFee + tx.NetworkFee + totalSenderFeeFromPool;
- return balance >= fee;
+ if (balance < fee) return false;
+
+ var oracle = tx.GetAttribute<OracleResponse>();
+ if (oracle != null && oracleResponses.ContainsKey(oracle.Id))
+ return false;
+
+ return true;
  }
 
  public void RemoveTransaction(Transaction tx)
  {
  if ((senderFee[tx.Sender] -= tx.SystemFee + tx.NetworkFee) == 0) senderFee.Remove(tx.Sender);
+
+ var oracle = tx.GetAttribute<OracleResponse>();
+ if (oracle != null) oracleResponses.Remove(oracle.Id);
  }
  }
 }

src/neo/SmartContract/Native/Oracle/OracleContract.cs

@@ -147,7 +147,8 @@ protected override void PostPersist(ApplicationEngine engine)
 
  //Remove the request from storage
  StorageKey key = CreateStorageKey(Prefix_Request).Add(response.Id);
- OracleRequest request = engine.Snapshot.Storages[key].GetInteroperable<OracleRequest>();
+ OracleRequest request = engine.Snapshot.Storages.TryGet(key)?.GetInteroperable<OracleRequest>();
+ if (request == null) continue;
  engine.Snapshot.Storages.Delete(key);
 
  //Remove the id from IdList
@@ -157,7 +158,7 @@ protected override void PostPersist(ApplicationEngine engine)
  if (list.Count == 0) engine.Snapshot.Storages.Delete(key);
 
  //Mint GAS for oracle nodes
- nodes ??= NativeContract.Designate.GetDesignatedByRole(engine.Snapshot, Role.Oracle, engine.Snapshot.PersistingBlock.Index).Select(p => (Contract.CreateSignatureRedeemScript(p).ToScriptHash(), BigInteger.Zero)).ToArray();
+ nodes ??= Designate.GetDesignatedByRole(engine.Snapshot, Role.Oracle, engine.Snapshot.PersistingBlock.Index).Select(p => (Contract.CreateSignatureRedeemScript(p).ToScriptHash(), BigInteger.Zero)).ToArray();
  if (nodes.Length > 0)
  {
  int index = (int)(response.Id % (ulong)nodes.Length);

tests/neo.UnitTests/Ledger/UT_TransactionVerificationContext.cs

@@ -47,6 +47,29 @@ private Transaction CreateTransactionWithFee(long networkFee, long systemFee)
  return mock.Object;
  }
 
+ [TestMethod]
+ public void TestDuplicateOracle()
+ {
+ // Fake balance
+ var snapshot = Blockchain.Singleton.GetSnapshot();
+
+ ApplicationEngine engine = ApplicationEngine.Create(TriggerType.Application, null, snapshot, long.MaxValue);
+ BigInteger balance = NativeContract.GAS.BalanceOf(snapshot, UInt160.Zero);
+ NativeContract.GAS.Burn(engine, UInt160.Zero, balance);
+ NativeContract.GAS.Mint(engine, UInt160.Zero, 8);
+
+ // Test
+ TransactionVerificationContext verificationContext = new TransactionVerificationContext();
+ var tx = CreateTransactionWithFee(1, 2);
+ tx.Attributes = new TransactionAttribute[] { new OracleResponse() { Code = OracleResponseCode.ConsensusUnreachable, Id = 1, Result = new byte[0] } };
+ verificationContext.CheckTransaction(tx, snapshot).Should().BeTrue();
+ verificationContext.AddTransaction(tx);
+
+ tx = CreateTransactionWithFee(2, 1);
+ tx.Attributes = new TransactionAttribute[] { new OracleResponse() { Code = OracleResponseCode.ConsensusUnreachable, Id = 1, Result = new byte[0] } };
+ verificationContext.CheckTransaction(tx, snapshot).Should().BeFalse();
+ }
+
  [TestMethod]
  public void TestTransactionSenderFee()
  {