From a7b10dbeceabca9c4ba0c09fc2658c9c765dbbc9 Mon Sep 17 00:00:00 2001
From: Jason Frame <jason.frame@consensys.net>
Date: Thu, 4 Apr 2024 17:33:35 +1000
Subject: [PATCH] Bws internal error fix (#6806)

Signed-off-by: Jason Frame <jason.frame@consensys.net>
---
 .../merge/blockcreation/MergeCoordinator.java      |  4 ----
 .../eth/sync/backwardsync/BackwardSyncContext.java | 12 ++++++++----
 .../sync/backwardsync/BackwardSyncContextTest.java | 14 ++++++++++++++
 3 files changed, 22 insertions(+), 8 deletions(-)

diff --git a/consensus/merge/src/main/java/org/hyperledger/besu/consensus/merge/blockcreation/MergeCoordinator.java b/consensus/merge/src/main/java/org/hyperledger/besu/consensus/merge/blockcreation/MergeCoordinator.java
index 512d2dc21f..e0b0559795 100644
--- a/consensus/merge/src/main/java/org/hyperledger/besu/consensus/merge/blockcreation/MergeCoordinator.java
+++ b/consensus/merge/src/main/java/org/hyperledger/besu/consensus/merge/blockcreation/MergeCoordinator.java
@@ -501,10 +501,6 @@ public class MergeCoordinator implements MergeMiningCoordinator, BadChainListene
           .addArgument(maybeHeadHeader.get()::toLogString)
           .log();
     } else {
-      LOG.atDebug()
-          .setMessage("Appending new head block hash {} to backward sync")
-          .addArgument(headHash::toHexString)
-          .log();
       backwardSyncContext.maybeUpdateTargetHeight(headHash);
       backwardSyncContext
           .syncBackwardsUntil(headHash)
diff --git a/ethereum/eth/src/main/java/org/hyperledger/besu/ethereum/eth/sync/backwardsync/BackwardSyncContext.java b/ethereum/eth/src/main/java/org/hyperledger/besu/ethereum/eth/sync/backwardsync/BackwardSyncContext.java
index 1c1382e06b..273dd56c78 100644
--- a/ethereum/eth/src/main/java/org/hyperledger/besu/ethereum/eth/sync/backwardsync/BackwardSyncContext.java
+++ b/ethereum/eth/src/main/java/org/hyperledger/besu/ethereum/eth/sync/backwardsync/BackwardSyncContext.java
@@ -125,11 +125,15 @@ public class BackwardSyncContext {
   }
 
   public synchronized CompletableFuture<Void> syncBackwardsUntil(final Hash newBlockHash) {
-    if (!isTrusted(newBlockHash)) {
-      backwardChain.addNewHash(newBlockHash);
-    }
-
     if (isReady()) {
+      if (!isTrusted(newBlockHash)) {
+        LOG.atDebug()
+            .setMessage("Appending new head block hash {} to backward sync")
+            .addArgument(newBlockHash::toHexString)
+            .log();
+        backwardChain.addNewHash(newBlockHash);
+      }
+
       final Status status = getOrStartSyncSession();
       backwardChain
           .getBlock(newBlockHash)
diff --git a/ethereum/eth/src/test/java/org/hyperledger/besu/ethereum/eth/sync/backwardsync/BackwardSyncContextTest.java b/ethereum/eth/src/test/java/org/hyperledger/besu/ethereum/eth/sync/backwardsync/BackwardSyncContextTest.java
index 532400c20d..ce4640ae93 100644
--- a/ethereum/eth/src/test/java/org/hyperledger/besu/ethereum/eth/sync/backwardsync/BackwardSyncContextTest.java
+++ b/ethereum/eth/src/test/java/org/hyperledger/besu/ethereum/eth/sync/backwardsync/BackwardSyncContextTest.java
@@ -231,6 +231,20 @@ public class BackwardSyncContextTest {
     assertThat(localBlockchain.getChainHeadBlock()).isEqualTo(remoteBlockchain.getChainHeadBlock());
   }
 
+  @Test
+  public void shouldNotSyncUntilHashWhenNotInSync() {
+    doReturn(false).when(context).isReady();
+    final Hash hash = getBlockByNumber(REMOTE_HEIGHT).getHash();
+    final CompletableFuture<Void> future = context.syncBackwardsUntil(hash);
+
+    respondUntilFutureIsDone(future);
+
+    assertThatThrownBy(future::get)
+        .isInstanceOf(ExecutionException.class)
+        .hasMessageContaining("Backward sync is not ready");
+    assertThat(backwardChain.getFirstHashToAppend()).isEmpty();
+  }
+
   @Test
   public void shouldSyncUntilRemoteBranch() throws Exception {