From 5dec71c9255889797b980378cf419627fdb1e255 Mon Sep 17 00:00:00 2001
From: Daniel Lehrner <daniel.lehrner@consensys.net>
Date: Wed, 12 Oct 2022 10:19:10 +0200
Subject: [PATCH] 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                                      |  1 +
 .../EngineExchangeTransitionConfiguration.java    | 15 +++++++++++++--
 ...eExchangeTransitionConfigurationParameter.java | 10 ++++++++++
 3 files changed, 24 insertions(+), 2 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index c86e28b93a2..a8115aa3193 100644
--- a/CHANGELOG.md
+++ b/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
 
diff --git a/ethereum/api/src/main/java/org/hyperledger/besu/ethereum/api/jsonrpc/internal/methods/engine/EngineExchangeTransitionConfiguration.java b/ethereum/api/src/main/java/org/hyperledger/besu/ethereum/api/jsonrpc/internal/methods/engine/EngineExchangeTransitionConfiguration.java
index 0633a438380..83686f60f62 100644
--- a/ethereum/api/src/main/java/org/hyperledger/besu/ethereum/api/jsonrpc/internal/methods/engine/EngineExchangeTransitionConfiguration.java
+++ b/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.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 JsonRpcResponse syncResponse(final JsonRpcRequestContext requestContext)
     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);
diff --git a/ethereum/api/src/main/java/org/hyperledger/besu/ethereum/api/jsonrpc/internal/parameters/EngineExchangeTransitionConfigurationParameter.java b/ethereum/api/src/main/java/org/hyperledger/besu/ethereum/api/jsonrpc/internal/parameters/EngineExchangeTransitionConfigurationParameter.java
index 61e7ccd982d..3833fa80c4f 100644
--- a/ethereum/api/src/main/java/org/hyperledger/besu/ethereum/api/jsonrpc/internal/parameters/EngineExchangeTransitionConfigurationParameter.java
+++ b/ethereum/api/src/main/java/org/hyperledger/besu/ethereum/api/jsonrpc/internal/parameters/EngineExchangeTransitionConfigurationParameter.java
@@ -39,10 +39,20 @@ public Difficulty getTerminalTotalDifficulty() {
     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;
   }