Fix evmtool JSON Error Field to Return Hex String Instead of Long Null String on REVERT (#7774)

Signed-off-by: 7at <itisfor@outlook.com>
Co-authored-by: Sally MacFarlane <macfarla.github@gmail.com>

ethereum/evmtool/src/main/java/org/hyperledger/besu/evmtool/EvmToolCommand.java

@@ -529,9 +529,7 @@ public class EvmToolCommand implements Runnable {
               messageFrame
                   .getExceptionalHaltReason()
                   .ifPresent(haltReason -> out.println(haltReason));
-              messageFrame
-                  .getRevertReason()
-                  .ifPresent(bytes -> out.println(new String(bytes.toArrayUnsafe(), UTF_8)));
+              messageFrame.getRevertReason().ifPresent(bytes -> out.println(bytes.toHexString()));
             }
           }
         }

ethereum/evmtool/src/test/resources/org/hyperledger/besu/evmtool/trace/revert.json

@@ -12,7 +12,7 @@
     {"pc":7,"op":82,"gas":"0x2540be3fa","gasCost":"0x6","memSize":0,"stack":["0x4e6f7065","0x0"],"depth":1,"refund":0,"opName":"MSTORE"},
     {"pc":8,"op":96,"gas":"0x2540be3f4","gasCost":"0x3","memSize":32,"stack":[],"depth":1,"refund":0,"opName":"PUSH1"},
     {"pc":10,"op":96,"gas":"0x2540be3f1","gasCost":"0x3","memSize":32,"stack":["0x4"],"depth":1,"refund":0,"opName":"PUSH1"},
-    {"pc":12,"op":253,"gas":"0x2540be3ee","gasCost":"0x0","memSize":32,"stack":["0x4","0x1c"],"depth":1,"refund":0,"opName":"REVERT","error":"Nope"},
+    {"pc":12,"op":253,"gas":"0x2540be3ee","gasCost":"0x0","memSize":32,"stack":["0x4","0x1c"],"depth":1,"refund":0,"opName":"REVERT","error":"0x4e6f7065"},
     {"stateRoot":"0x405bbd98da2aca6dff77f79e0b270270c48d6a3e07b76db675b20e454b50bbcb","output":"0x4e6f7065","gasUsed":"0x12","pass":true,"fork":"Cancun"}
   ]
 }

evm/src/main/java/org/hyperledger/besu/evm/tracing/StandardJsonTracer.java

@@ -14,8 +14,6 @@
  */
 package org.hyperledger.besu.evm.tracing;
 
-import static com.google.common.base.Strings.padStart;
-
 import org.hyperledger.besu.evm.code.OpcodeInfo;
 import org.hyperledger.besu.evm.frame.ExceptionalHaltReason;
 import org.hyperledger.besu.evm.frame.MessageFrame;
@@ -224,7 +222,7 @@ public class StandardJsonTracer implements OperationTracer {
           .append("\"");
     } else if (messageFrame.getRevertReason().isPresent()) {
       sb.append(",\"error\":\"")
-          .append(quoteEscape(messageFrame.getRevertReason().orElse(Bytes.EMPTY)))
+          .append(messageFrame.getRevertReason().get().toHexString())
           .append("\"");
     }
 
@@ -232,37 +230,6 @@ public class StandardJsonTracer implements OperationTracer {
     out.println(sb);
   }
 
-  private static String quoteEscape(final Bytes bytes) {
-    final StringBuilder result = new StringBuilder(bytes.size());
-    for (final byte b : bytes.toArrayUnsafe()) {
-      final int c = Byte.toUnsignedInt(b);
-      // list from RFC-4627 section 2
-      if (c == '"') {
-        result.append("\\\"");
-      } else if (c == '\\') {
-        result.append("\\\\");
-      } else if (c == '/') {
-        result.append("\\/");
-      } else if (c == '\b') {
-        result.append("\\b");
-      } else if (c == '\f') {
-        result.append("\\f");
-      } else if (c == '\n') {
-        result.append("\\n");
-      } else if (c == '\r') {
-        result.append("\\r");
-      } else if (c == '\t') {
-        result.append("\\t");
-      } else if (c <= 0x1F) {
-        result.append("\\u");
-        result.append(padStart(Integer.toHexString(c), 4, '0'));
-      } else {
-        result.append((char) b);
-      }
-    }
-    return result.toString();
-  }
-
   @Override
   public void tracePrecompileCall(
       final MessageFrame frame, final long gasRequirement, final Bytes output) {

evm/src/test/java/org/hyperledger/besu/evm/toy/EvmToyCommand.java

@@ -32,7 +32,6 @@ import org.hyperledger.besu.evm.worldstate.WorldUpdater;
 
 import java.io.PrintStream;
 import java.math.BigInteger;
-import java.nio.charset.StandardCharsets;
 import java.util.Deque;
 import java.util.List;
 
@@ -208,9 +207,7 @@ public class EvmToyCommand implements Runnable {
             out.println(messageFrame.getExceptionalHaltReason().get());
           }
           if (messageFrame.getRevertReason().isPresent()) {
-            out.println(
-                new String(
-                    messageFrame.getRevertReason().get().toArrayUnsafe(), StandardCharsets.UTF_8));
+            out.println(messageFrame.getRevertReason().get().toHexString());
           }
         }
         if (messageFrameStack.isEmpty()) {