#93 fix for collision storage clearing - REVERT fix pending

src/Nethermind/Nethermind.Blockchain/BlockchainProcessor.cs

@@ -19,7 +19,6 @@
 using System;
 using System.Collections.Concurrent;
 using System.Collections.Generic;
-using System.Diagnostics;
 using System.Threading;
 using System.Threading.Tasks;
 using Nethermind.Blockchain.Validators;

src/Nethermind/Nethermind.Evm/VirtualMachine.cs

@@ -2151,17 +2151,19 @@ void UpdateMemoryCost(UInt256 position, UInt256 length)
 
  _state.IncrementNonce(env.ExecutingAccount);
 
+ int stateSnapshot = _state.TakeSnapshot();
+ int storageSnapshot = _storage.TakeSnapshot();
+
  bool accountExists = _state.AccountExists(contractAddress);
  if (accountExists && ((GetCachedCodeInfo(contractAddress)?.MachineCode?.Length ?? 0) != 0 || _state.GetNonce(contractAddress) != 0))
  {
+ /* we get the snapshot before this as there is a possibility with that we will touch an empty account and remove it even if the REVERT operation follows */
  if (_logger.IsTrace) _logger.Trace($"Contract collision at {contractAddress}");
- PushZero(bytesOnStack); // TODO: this push 0 approach should be replaced with some proper approach to call result
+ PushZero(bytesOnStack);
  break;
  }
-
- int stateSnapshot = _state.TakeSnapshot();
- int storageSnapshot = _storage.TakeSnapshot();
-
+
+ _state.UpdateStorageRoot(contractAddress, Keccak.EmptyTreeHash);
  _state.SubtractFromBalance(env.ExecutingAccount, value, spec); 
  ExecutionEnvironment callEnv = new ExecutionEnvironment();
  callEnv.TransferValue = value;