detect deploy of bytecode and use proper error message

Author: kroggen

contract/vm.go

@@ -955,11 +955,16 @@ func setContract(contractState *statedb.ContractState, contractAddress, payload
 
 	// if hardfork version 4
 	if ctx.blockInfo.ForkVersion >= 4 {
+		// check for LuaJIT bytecode signature at position 4
+		if len(code) > 8 && bytes.HasPrefix(code[4:], []byte{0x1b, 0x4c, 0x4a}) {
+			ctrLgr.Info().Str("contract", types.EncodeAddress(contractAddress)).Msg("unexpected bytecode on deploy")
+			return nil, nil, errors.New("deploy bytecode is not supported. send the plain source code instead")
+		}
 		// the payload must be lua code. compile it to bytecode
 		sourceCode = code
 		bytecodeABI, err = Compile(string(sourceCode), nil)
 		if err != nil {
-			ctrLgr.Warn().Err(err).Str("contract", types.EncodeAddress(contractAddress)).Msg("deploy")
+			ctrLgr.Warn().Err(err).Str("contract", types.EncodeAddress(contractAddress)).Msg("deploy - compile error")
 			return nil, nil, err
 		}
 	} else {