Fix Oracle PostPersist

src/neo/Ledger/TransactionVerificationContext.cs

@@ -13,25 +13,48 @@ public class TransactionVerificationContext
         /// </summary>
         private readonly Dictionary<UInt160, BigInteger> senderFee = new Dictionary<UInt160, BigInteger>();
 
+        /// <summary>
+        /// Store oracle requests
+        /// </summary>
+        private readonly Dictionary<ulong, UInt256> oracleRequests = new Dictionary<ulong, UInt256>();
+
         public void AddTransaction(Transaction tx)
         {
             if (senderFee.TryGetValue(tx.Sender, out var value))
                 senderFee[tx.Sender] = value + tx.SystemFee + tx.NetworkFee;
             else
                 senderFee.Add(tx.Sender, tx.SystemFee + tx.NetworkFee);
+
+            var oracle = tx.GetAttribute<OracleResponse>();
+            if (oracle != null) oracleRequests.TryAdd(oracle.Id, tx.Hash);
         }
 
         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 &&
+                (!oracleRequests.TryGetValue(oracle.Id, out var hash) || hash != tx.Hash))
+            {
+                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 && oracleRequests.TryGetValue(oracle.Id, out var hash) && hash == tx.Hash)
+            {
+                oracleRequests.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);