graph/db: version FilterKnownChanIDs callback

diff --git a/discovery/chan_series.go b/discovery/chan_series.go
index 7ed9bbd..4a9a519 100644
--- a/discovery/chan_series.go
+++ b/discovery/chan_series.go
@@ -40,7 +40,7 @@ type ChannelGraphTimeSeries interface {
 	// passed superSet.
 	FilterKnownChanIDs(chain chainhash.Hash,
 		superSet []graphdb.ChannelUpdateInfo,
-		isZombieChan func(time.Time, time.Time) bool) (
+		isZombieChan func(graphdb.ChannelUpdateInfo) bool) (
 		[]lnwire.ShortChannelID, error)
 
 	// FilterChannelRange returns the set of channels that we created
@@ -212,7 +212,7 @@ func (c *ChanSeries) UpdatesInHorizon(chain chainhash.Hash,
 // NOTE: This is part of the ChannelGraphTimeSeries interface.
 func (c *ChanSeries) FilterKnownChanIDs(_ chainhash.Hash,
 	superSet []graphdb.ChannelUpdateInfo,
-	isZombieChan func(time.Time, time.Time) bool) (
+	isZombieChan func(graphdb.ChannelUpdateInfo) bool) (
 	[]lnwire.ShortChannelID, error) {
 
 	newChanIDs, err := c.graph.FilterKnownChanIDs(
diff --git a/discovery/syncer.go b/discovery/syncer.go
index 37f6705..ff0baf6 100644
--- a/discovery/syncer.go
+++ b/discovery/syncer.go
@@ -975,7 +975,7 @@ func (g *GossipSyncer) processChanRangeReply(_ context.Context,
 
 	for i, scid := range msg.ShortChanIDs {
 		info := graphdb.NewChannelUpdateInfo(
-			scid, time.Time{}, time.Time{},
+			scid, lnwire.GossipVersion1, time.Time{}, time.Time{},
 		)
 
 		if len(msg.Timestamps) != 0 {
@@ -1061,9 +1061,17 @@ func (g *GossipSyncer) processChanRangeReply(_ context.Context,
 
 	// Otherwise, this is the final response, so we'll now check to see
 	// which channels they know of that we don't.
+	// TODO(elle): isStillZombieChannel only inspects v1 time-based
+	// timestamps; once the gossip sync protocol supports v2, this
+	// should be updated to handle block-height freshness for v2
+	// channels.
+	isZombieChan := func(info graphdb.ChannelUpdateInfo) bool {
+		return g.cfg.isStillZombieChannel(
+			info.Node1UpdateTimestamp, info.Node2UpdateTimestamp,
+		)
+	}
 	newChans, err := g.cfg.channelSeries.FilterKnownChanIDs(
-		g.cfg.chainHash, g.bufferedChanRangeReplies,
-		g.cfg.isStillZombieChannel,
+		g.cfg.chainHash, g.bufferedChanRangeReplies, isZombieChan,
 	)
 	if err != nil {
 		return fmt.Errorf("unable to filter chan ids: %w", err)
diff --git a/discovery/syncer_test.go b/discovery/syncer_test.go
index 2313d1c..cbf4c1d 100644
--- a/discovery/syncer_test.go
+++ b/discovery/syncer_test.go
@@ -108,7 +108,7 @@ func (m *mockChannelGraphTimeSeries) UpdatesInHorizon(chain chainhash.Hash,
 
 func (m *mockChannelGraphTimeSeries) FilterKnownChanIDs(chain chainhash.Hash,
 	superSet []graphdb.ChannelUpdateInfo,
-	isZombieChan func(time.Time, time.Time) bool) (
+	isZombieChan func(graphdb.ChannelUpdateInfo) bool) (
 	[]lnwire.ShortChannelID, error) {
 
 	m.filterReq <- superSet
diff --git a/graph/db/graph.go b/graph/db/graph.go
index b98a806..a082d5b 100644
--- a/graph/db/graph.go
+++ b/graph/db/graph.go
@@ -522,7 +522,7 @@ func (c *ChannelGraph) PruneGraphNodes(ctx context.Context) error {
 // channels another peer knows of that we don't.
 func (c *ChannelGraph) FilterKnownChanIDs(ctx context.Context,
 	chansInfo []ChannelUpdateInfo,
-	isZombieChan func(time.Time, time.Time) bool) ([]uint64, error) {
+	isZombieChan func(ChannelUpdateInfo) bool) ([]uint64, error) {
 
 	unknown, knownZombies, err := c.db.FilterKnownChanIDs(ctx, chansInfo)
 	if err != nil {
@@ -541,20 +541,16 @@ func (c *ChannelGraph) FilterKnownChanIDs(ctx context.Context,
 		// recent. During the querying of the gossip msg verification
 		// happens as usual. However we should start punishing peers
 		// when they don't provide us honest data ?
-		isStillZombie := isZombieChan(
-			info.Node1UpdateTimestamp, info.Node2UpdateTimestamp,
-		)
-
-		if isStillZombie {
+		if isZombieChan(info) {
 			continue
 		}
 
 		// If we have marked it as a zombie but the latest update
-		// timestamps could bring it back from the dead, then we mark it
+		// info could bring it back from the dead, then we mark it
 		// alive, and we let it be added to the set of IDs to query our
 		// peer for.
 		err := c.db.MarkEdgeLive(
-			ctx, lnwire.GossipVersion1,
+			ctx, info.Version,
 			info.ShortChannelID.ToUint64(),
 		)
 		// Since there is a chance that the edge could have been marked
diff --git a/graph/db/graph_test.go b/graph/db/graph_test.go
index f49eb3a..06c278d 100644
--- a/graph/db/graph_test.go
+++ b/graph/db/graph_test.go
@@ -2979,10 +2979,10 @@ func TestFilterKnownChanIDsZombieRevival(t *testing.T) {
 	// Call FilterKnownChanIDs with an isStillZombie call-back that would
 	// result in the current zombies still be considered as zombies.
 	_, err = graph.FilterKnownChanIDs(ctx, []ChannelUpdateInfo{
-		{ShortChannelID: scid1},
-		{ShortChannelID: scid2},
-		{ShortChannelID: scid3},
-	}, func(_ time.Time, _ time.Time) bool {
+		{ShortChannelID: scid1, Version: lnwire.GossipVersion1},
+		{ShortChannelID: scid2, Version: lnwire.GossipVersion1},
+		{ShortChannelID: scid3, Version: lnwire.GossipVersion1},
+	}, func(_ ChannelUpdateInfo) bool {
 		return true
 	})
 	require.NoError(t, err)
@@ -2995,14 +2995,15 @@ func TestFilterKnownChanIDsZombieRevival(t *testing.T) {
 	// would result in channel with SCID 2 no longer being considered a
 	// zombie.
 	_, err = graph.FilterKnownChanIDs(ctx, []ChannelUpdateInfo{
-		{ShortChannelID: scid1},
+		{ShortChannelID: scid1, Version: lnwire.GossipVersion1},
 		{
 			ShortChannelID:       scid2,
+			Version:              lnwire.GossipVersion1,
 			Node1UpdateTimestamp: time.Unix(1000, 0),
 		},
-		{ShortChannelID: scid3},
-	}, func(t1 time.Time, _ time.Time) bool {
-		return !t1.Equal(time.Unix(1000, 0))
+		{ShortChannelID: scid3, Version: lnwire.GossipVersion1},
+	}, func(info ChannelUpdateInfo) bool {
+		return !info.Node1UpdateTimestamp.Equal(time.Unix(1000, 0))
 	})
 	require.NoError(t, err)
 
@@ -3021,9 +3022,7 @@ func TestFilterKnownChanIDs(t *testing.T) {
 
 	graph := MakeTestGraph(t)
 
-	isZombieUpdate := func(updateTime1 time.Time,
-		updateTime2 time.Time) bool {
-
+	isZombieUpdate := func(_ ChannelUpdateInfo) bool {
 		return true
 	}
 
@@ -3068,7 +3067,7 @@ func TestFilterKnownChanIDs(t *testing.T) {
 		require.NoError(t, graph.AddChannelEdge(ctx, channel))
 
 		chanIDs = append(chanIDs, NewChannelUpdateInfo(
-			chanID, time.Time{}, time.Time{},
+			chanID, lnwire.GossipVersion1, time.Time{}, time.Time{},
 		))
 	}
 
@@ -3347,7 +3346,7 @@ func TestStressTestChannelGraphAPI(t *testing.T) {
 
 				_, err := graph.FilterKnownChanIDs(
 					ctx, chanIDs,
-					func(t time.Time, t2 time.Time) bool {
+					func(_ ChannelUpdateInfo) bool {
 						return rand.Intn(2) == 0
 					},
 				)
@@ -3565,10 +3564,12 @@ func TestFilterChannelRange(t *testing.T) {
 		require.NoError(t, graph.AddChannelEdge(ctx, channel2))
 
 		chanInfo1 := NewChannelUpdateInfo(
-			chanID1, time.Time{}, time.Time{},
+			chanID1, lnwire.GossipVersion1,
+			time.Time{}, time.Time{},
 		)
 		chanInfo2 := NewChannelUpdateInfo(
-			chanID2, time.Time{}, time.Time{},
+			chanID2, lnwire.GossipVersion1,
+			time.Time{}, time.Time{},
 		)
 		channelRanges = append(channelRanges, BlockChannelRange{
 			Height: chanHeight,
@@ -3585,10 +3586,10 @@ func TestFilterChannelRange(t *testing.T) {
 		)
 
 		chanInfo1 = NewChannelUpdateInfo(
-			chanID1, time1, time2,
+			chanID1, lnwire.GossipVersion1, time1, time2,
 		)
 		chanInfo2 = NewChannelUpdateInfo(
-			chanID2, time3, time4,
+			chanID2, lnwire.GossipVersion1, time3, time4,
 		)
 		channelRangesWithTimestamps = append(
 			channelRangesWithTimestamps, BlockChannelRange{
@@ -4610,9 +4611,8 @@ func TestGraphZombieIndex(t *testing.T) {
 
 	// Similarly, if we mark the same edge as live, we should no longer see
 	// it within the index.
-	require.NoError(
-		t, graph.MarkEdgeLive(ctx, lnwire.GossipVersion1, edge.ChannelID),
-	)
+	err = graph.MarkEdgeLive(ctx, lnwire.GossipVersion1, edge.ChannelID)
+	require.NoError(t, err)
 
 	// Attempting to mark the edge as live again now that it is no longer
 	// in the zombie index should fail.
diff --git a/graph/db/kv_store.go b/graph/db/kv_store.go
index 5e911aa..2ed7fc9 100644
--- a/graph/db/kv_store.go
+++ b/graph/db/kv_store.go
@@ -2764,6 +2764,9 @@ type ChannelUpdateInfo struct {
 	// ShortChannelID is the SCID identifier of the channel.
 	ShortChannelID lnwire.ShortChannelID
 
+	// Version is the gossip version of the channel.
+	Version lnwire.GossipVersion
+
 	// Node1UpdateTimestamp is the timestamp of the latest received update
 	// from the node 1 channel peer. This will be set to zero time if no
 	// update has yet been received from this node.
@@ -2778,11 +2781,13 @@ type ChannelUpdateInfo struct {
 // NewChannelUpdateInfo is a constructor which makes sure we initialize the
 // timestamps with zero seconds unix timestamp which equals
 // `January 1, 1970, 00:00:00 UTC` in case the value is `time.Time{}`.
-func NewChannelUpdateInfo(scid lnwire.ShortChannelID, node1Timestamp,
+func NewChannelUpdateInfo(scid lnwire.ShortChannelID,
+	v lnwire.GossipVersion, node1Timestamp,
 	node2Timestamp time.Time) ChannelUpdateInfo {
 
 	chanInfo := ChannelUpdateInfo{
 		ShortChannelID:       scid,
+		Version:              v,
 		Node1UpdateTimestamp: node1Timestamp,
 		Node2UpdateTimestamp: node2Timestamp,
 	}
@@ -2874,7 +2879,7 @@ func (c *KVStore) FilterChannelRange(_ context.Context, startHeight,
 			cid := lnwire.NewShortChanIDFromInt(rawCid)
 
 			chanInfo := NewChannelUpdateInfo(
-				cid, time.Time{}, time.Time{},
+				cid, lnwire.GossipVersion1, time.Time{}, time.Time{},
 			)
 
 			if !withTimestamps {
diff --git a/graph/db/sql_store.go b/graph/db/sql_store.go
index 7536721..173e0dc 100644
--- a/graph/db/sql_store.go
+++ b/graph/db/sql_store.go
@@ -1703,7 +1703,8 @@ func (s *SQLStore) FilterChannelRange(ctx context.Context, startHeight,
 				byteOrder.Uint64(dbChan.Scid),
 			)
 			chanInfo := NewChannelUpdateInfo(
-				cid, time.Time{}, time.Time{},
+				cid, lnwire.GossipVersion1,
+				time.Time{}, time.Time{},
 			)
 
 			if !withTimestamps {