From 7479f5f5e81af6cb9f3d8c37d218e09ac7490ec8 Mon Sep 17 00:00:00 2001
From: stasatdaglabs <39559713+stasatdaglabs@users.noreply.github.com>
Date: Tue, 17 Nov 2020 16:40:55 +0200
Subject: [PATCH] [NOD-1545] Fix incorrect block difficulty calculation in
 buildHeader. (#1102)

---
 .../processes/blockbuilder/block_builder.go        | 14 +++-----------
 .../processes/blockbuilder/test_block_builder.go   |  7 +------
 2 files changed, 4 insertions(+), 17 deletions(-)

diff --git a/domain/consensus/processes/blockbuilder/block_builder.go b/domain/consensus/processes/blockbuilder/block_builder.go
index 1c30f2135..db34a4105 100644
--- a/domain/consensus/processes/blockbuilder/block_builder.go
+++ b/domain/consensus/processes/blockbuilder/block_builder.go
@@ -100,15 +100,11 @@ func (bb *blockBuilder) buildHeader(transactions []*externalapi.DomainTransactio
 	if err != nil {
 		return nil, err
 	}
-	virtualGHOSTDAGData, err := bb.ghostdagDataStore.Get(bb.databaseContext, model.VirtualBlockHash)
-	if err != nil {
-		return nil, err
-	}
 	timeInMilliseconds, err := bb.newBlockTime()
 	if err != nil {
 		return nil, err
 	}
-	bits, err := bb.newBlockDifficulty(virtualGHOSTDAGData)
+	bits, err := bb.newBlockDifficulty()
 	if err != nil {
 		return nil, err
 	}
@@ -160,12 +156,8 @@ func (bb *blockBuilder) newBlockTime() (int64, error) {
 	return newTimestamp, nil
 }
 
-func (bb *blockBuilder) newBlockDifficulty(virtualGHOSTDAGData *model.BlockGHOSTDAGData) (uint32, error) {
-	virtualGHOSTDAGData, err := bb.ghostdagDataStore.Get(bb.databaseContext, model.VirtualBlockHash)
-	if err != nil {
-		return 0, err
-	}
-	return bb.difficultyManager.RequiredDifficulty(virtualGHOSTDAGData.SelectedParent)
+func (bb *blockBuilder) newBlockDifficulty() (uint32, error) {
+	return bb.difficultyManager.RequiredDifficulty(model.VirtualBlockHash)
 }
 
 func (bb *blockBuilder) newBlockHashMerkleRoot(transactions []*externalapi.DomainTransaction) *externalapi.DomainHash {
diff --git a/domain/consensus/processes/blockbuilder/test_block_builder.go b/domain/consensus/processes/blockbuilder/test_block_builder.go
index 7b9236160..addcaa558 100644
--- a/domain/consensus/processes/blockbuilder/test_block_builder.go
+++ b/domain/consensus/processes/blockbuilder/test_block_builder.go
@@ -39,16 +39,11 @@ func (bb testBlockBuilder) buildHeaderWithParents(parentHashes []*externalapi.Do
 	transactions []*externalapi.DomainTransaction, acceptanceData model.AcceptanceData, multiset model.Multiset) (
 	*externalapi.DomainBlockHeader, error) {
 
-	ghostdagData, err := bb.ghostdagDataStore.Get(bb.databaseContext, tempBlockHash)
-	if err != nil {
-		return nil, err
-	}
-
 	timeInMilliseconds, err := bb.pastMedianTimeManager.PastMedianTime(tempBlockHash)
 	if err != nil {
 		return nil, err
 	}
-	bits, err := bb.newBlockDifficulty(ghostdagData)
+	bits, err := bb.newBlockDifficulty()
 	if err != nil {
 		return nil, err
 	}