From 00853c2fcf9c58f183552528950b6929345f3d1d Mon Sep 17 00:00:00 2001
From: Gabriel-Trintinalia <gabriel.trintinalia@consensys.net>
Date: Thu, 28 Sep 2023 22:27:47 +1000
Subject: [PATCH] Validate bad block before new head check syncing (#5967)

Signed-off-by: Gabriel-Trintinalia <gabriel.trintinalia@consensys.net>
---
 .../AbstractEngineForkchoiceUpdated.java      | 26 +++++++++----------
 1 file changed, 13 insertions(+), 13 deletions(-)

diff --git a/ethereum/api/src/main/java/org/hyperledger/besu/ethereum/api/jsonrpc/internal/methods/engine/AbstractEngineForkchoiceUpdated.java b/ethereum/api/src/main/java/org/hyperledger/besu/ethereum/api/jsonrpc/internal/methods/engine/AbstractEngineForkchoiceUpdated.java
index 8e471e2a113..511300d1090 100644
--- a/ethereum/api/src/main/java/org/hyperledger/besu/ethereum/api/jsonrpc/internal/methods/engine/AbstractEngineForkchoiceUpdated.java
+++ b/ethereum/api/src/main/java/org/hyperledger/besu/ethereum/api/jsonrpc/internal/methods/engine/AbstractEngineForkchoiceUpdated.java
@@ -93,6 +93,19 @@ public JsonRpcResponse syncResponse(final JsonRpcRequestContext requestContext)
             forkChoice.getSafeBlockHash(),
             forkChoice.getFinalizedBlockHash());
 
+    if (mergeCoordinator.isBadBlock(forkChoice.getHeadBlockHash())) {
+      logForkchoiceUpdatedCall(INVALID, forkChoice);
+      return new JsonRpcSuccessResponse(
+          requestId,
+          new EngineUpdateForkchoiceResult(
+              INVALID,
+              mergeCoordinator
+                  .getLatestValidHashOfBadBlock(forkChoice.getHeadBlockHash())
+                  .orElse(Hash.ZERO),
+              null,
+              Optional.of(forkChoice.getHeadBlockHash() + " is an invalid block")));
+    }
+
     final Optional<BlockHeader> maybeNewHead =
         mergeCoordinator.getOrSyncHeadByHash(
             forkChoice.getHeadBlockHash(), forkChoice.getFinalizedBlockHash());
@@ -150,19 +163,6 @@ public JsonRpcResponse syncResponse(final JsonRpcRequestContext requestContext)
       return syncingResponse(requestId, forkChoice);
     }
 
-    if (mergeCoordinator.isBadBlock(forkChoice.getHeadBlockHash())) {
-      logForkchoiceUpdatedCall(INVALID, forkChoice);
-      return new JsonRpcSuccessResponse(
-          requestId,
-          new EngineUpdateForkchoiceResult(
-              INVALID,
-              mergeCoordinator
-                  .getLatestValidHashOfBadBlock(forkChoice.getHeadBlockHash())
-                  .orElse(Hash.ZERO),
-              null,
-              Optional.of(forkChoice.getHeadBlockHash() + " is an invalid block")));
-    }
-
     maybePayloadAttributes.ifPresentOrElse(
         this::logPayload, () -> LOG.debug("Payload attributes are null"));