From d8f72e2b27bab86e8e6a7face03dced556cbbd1f Mon Sep 17 00:00:00 2001
From: Mike Zak <feanorr@gmail.com>
Date: Mon, 16 Nov 2020 15:58:05 +0200
Subject: [PATCH] [NOD-1532] Update VirtualUTXODiffParents diffs even if list
 didn't change

---
 .../calculate_past_utxo.go                    | 17 +++++-----
 .../consensusstatemanager/update_virtual.go   | 32 +++++++++----------
 2 files changed, 24 insertions(+), 25 deletions(-)

diff --git a/domain/consensus/processes/consensusstatemanager/calculate_past_utxo.go b/domain/consensus/processes/consensusstatemanager/calculate_past_utxo.go
index f2b8d48ea..7cbef09cb 100644
--- a/domain/consensus/processes/consensusstatemanager/calculate_past_utxo.go
+++ b/domain/consensus/processes/consensusstatemanager/calculate_past_utxo.go
@@ -1,10 +1,9 @@
 package consensusstatemanager
 
 import (
-	"errors"
-
 	"github.com/kaspanet/kaspad/domain/consensus/utils/constants"
 	"github.com/kaspanet/kaspad/domain/consensus/utils/multiset"
+	"github.com/pkg/errors"
 
 	"github.com/kaspanet/kaspad/domain/consensus/model"
 	"github.com/kaspanet/kaspad/domain/consensus/model/externalapi"
@@ -186,7 +185,7 @@ func (csm *consensusStateManager) checkTransactionMass(
 }
 
 func (csm *consensusStateManager) RestorePastUTXOSetIterator(blockHash *externalapi.DomainHash) (model.ReadOnlyUTXOSetIterator, error) {
-	diff, _, _, err := csm.CalculatePastUTXOAndAcceptanceData(blockHash)
+	blockDiff, _, _, err := csm.CalculatePastUTXOAndAcceptanceData(blockHash)
 	if err != nil {
 		return nil, err
 	}
@@ -196,25 +195,25 @@ func (csm *consensusStateManager) RestorePastUTXOSetIterator(blockHash *external
 		return nil, err
 	}
 
-	pastUTXO := model.NewUTXODiff()
+	virtualUTXO := model.NewUTXODiff()
 	for virtualUTXOSetIterator.Next() {
 		outpoint, utxoEntry, err := virtualUTXOSetIterator.Get()
 		if err != nil {
 			return nil, err
 		}
-		pastUTXO.ToAdd[*outpoint] = utxoEntry
+		virtualUTXO.ToAdd[*outpoint] = utxoEntry
 	}
 
-	diff, err = utxoalgebra.WithDiff(pastUTXO, diff)
+	blockUTXO, err := utxoalgebra.WithDiff(virtualUTXO, blockDiff)
 	if err != nil {
 		return nil, err
 	}
 
-	if len(diff.ToRemove) > 0 {
-		return nil, errors.New("diff.ToRemove is expected to be empty")
+	if len(blockUTXO.ToRemove) > 0 {
+		return nil, errors.New("blockUTXO.ToRemove is expected to be empty")
 	}
 
-	return newUTXOSetIterator(diff.ToAdd), nil
+	return newUTXOSetIterator(blockUTXO.ToAdd), nil
 }
 
 type utxoOutpointEntryPair struct {
diff --git a/domain/consensus/processes/consensusstatemanager/update_virtual.go b/domain/consensus/processes/consensusstatemanager/update_virtual.go
index 10c113ab2..fb0df7df4 100644
--- a/domain/consensus/processes/consensusstatemanager/update_virtual.go
+++ b/domain/consensus/processes/consensusstatemanager/update_virtual.go
@@ -51,34 +51,34 @@ func (csm *consensusStateManager) updateVirtual(newBlockHash *externalapi.Domain
 func (csm *consensusStateManager) updateVirtualDiffParents(
 	newBlockHash *externalapi.DomainHash, virtualUTXODiff *model.UTXODiff) error {
 
-	// If the status of the new block is not `Valid` - virtualDiffParents didn't change
-	status, err := csm.blockStatusStore.Get(csm.databaseContext, newBlockHash)
-	if err != nil {
-		return err
-	}
-	if status != externalapi.StatusValid {
-		return nil
-	}
-
 	var newVirtualDiffParents []*externalapi.DomainHash
 	if *newBlockHash == *csm.genesisHash {
 		newVirtualDiffParents = []*externalapi.DomainHash{newBlockHash}
 	} else {
-		virtualDiffParents, err := csm.consensusStateStore.VirtualDiffParents(csm.databaseContext)
+		oldVirtualDiffParents, err := csm.consensusStateStore.VirtualDiffParents(csm.databaseContext)
 		if err != nil {
 			return err
 		}
 
-		newBlockParentsSlice, err := csm.dagTopologyManager.Parents(newBlockHash)
+		// If the status of the new block is not `Valid` - virtualDiffParents didn't change
+		status, err := csm.blockStatusStore.Get(csm.databaseContext, newBlockHash)
 		if err != nil {
 			return err
 		}
-		newBlockParents := hashset.NewFromSlice(newBlockParentsSlice...)
+		if status != externalapi.StatusValid {
+			newVirtualDiffParents = oldVirtualDiffParents
+		} else {
+			newBlockParentsSlice, err := csm.dagTopologyManager.Parents(newBlockHash)
+			if err != nil {
+				return err
+			}
+			newBlockParents := hashset.NewFromSlice(newBlockParentsSlice...)
 
-		newVirtualDiffParents = []*externalapi.DomainHash{newBlockHash}
-		for _, virtualDiffParent := range virtualDiffParents {
-			if !newBlockParents.Contains(virtualDiffParent) {
-				newVirtualDiffParents = append(newVirtualDiffParents, virtualDiffParent)
+			newVirtualDiffParents = []*externalapi.DomainHash{newBlockHash}
+			for _, virtualDiffParent := range oldVirtualDiffParents {
+				if !newBlockParents.Contains(virtualDiffParent) {
+					newVirtualDiffParents = append(newVirtualDiffParents, virtualDiffParent)
+				}
 			}
 		}
 	}