Avoid a cyclic reference while printing EngineExchangeTransitionConfigurationParameter (#4357)

* avoids a cyclic reference while printing EngineExchangeTransitionConfigurationParameter

Signed-off-by: Daniel Lehrner <daniel.lehrner@consensys.net>

CHANGELOG.md

@@ -15,6 +15,7 @@
 ### Bug Fixes
 - Corrects emission of blockadded events when rewinding during a re-org. Fix for [#4495](https://github.com/hyperledger/besu/issues/4495)
 - Always return a transaction type for pending transactions [#4364](https://github.com/hyperledger/besu/pull/4364)
+- Avoid a cyclic reference while printing EngineExchangeTransitionConfigurationParameter [#4357](https://github.com/hyperledger/besu/pull/4357)
 
 ### Download Links
 

ethereum/api/src/main/java/org/hyperledger/besu/ethereum/api/jsonrpc/internal/methods/engine/EngineExchangeTransitionConfiguration.java

@@ -30,9 +30,12 @@ import org.hyperledger.besu.ethereum.core.BlockHeader;
 import org.hyperledger.besu.ethereum.core.Difficulty;
 
 import java.util.Optional;
+import java.util.function.Supplier;
 
+import com.fasterxml.jackson.core.JsonProcessingException;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.google.common.base.Suppliers;
 import io.vertx.core.Vertx;
-import io.vertx.core.json.Json;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -45,6 +48,8 @@ public class EngineExchangeTransitionConfiguration extends ExecutionEngineJsonRp
       Difficulty.fromHexString(
           "0xfffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffc00");
 
+  private static final Supplier<ObjectMapper> mapperSupplier = Suppliers.memoize(ObjectMapper::new);
+
   public EngineExchangeTransitionConfiguration(
       final Vertx vertx,
       final ProtocolContext protocolContext,
@@ -69,7 +74,13 @@ public class EngineExchangeTransitionConfiguration extends ExecutionEngineJsonRp
     traceLambda(
         LOG,
         "received transitionConfiguration: {}",
-        () -> Json.encodePrettily(remoteTransitionConfiguration));
+        () -> {
+          try {
+            return mapperSupplier.get().writeValueAsString(remoteTransitionConfiguration);
+          } catch (JsonProcessingException e) {
+            throw new RuntimeException(e);
+          }
+        });
 
     final Optional<BlockHeader> maybeTerminalPoWBlockHeader =
         mergeContextOptional.flatMap(MergeContext::getTerminalPoWBlock);

ethereum/api/src/main/java/org/hyperledger/besu/ethereum/api/jsonrpc/internal/parameters/EngineExchangeTransitionConfigurationParameter.java

@@ -39,10 +39,20 @@ public class EngineExchangeTransitionConfigurationParameter {
     return terminalTotalDifficulty;
   }
 
+  @JsonProperty("terminalTotalDifficulty")
+  public String getTerminalTotalDifficultyAsHexString() {
+    return terminalTotalDifficulty.toShortHexString();
+  }
+
   public Hash getTerminalBlockHash() {
     return terminalBlockHash;
   }
 
+  @JsonProperty("terminalBlockHash")
+  public String getTerminalBlockHashAsHexString() {
+    return terminalBlockHash.toShortHexString();
+  }
+
   public long getTerminalBlockNumber() {
     return terminalBlockNumber;
   }