graph/db: add sql support for versioned node traversal

Add SQL queries for version-aware node traversal used by the
sqlNodeTraverser: ListChannelsForNodeV2, GetV2NodesByPubKeys,
ListChannelsWithPoliciesForCachePaginatedV2, and
ListChannelsPaginatedV2.

Update the KV store's ForEachNodeDirectedChannel to return
ErrVersionNotSupportedForKVDB for non-v1 instead of silently
returning no results.

Author: ellemouton

graph/db/graph_test.go

@@ -3000,13 +3000,11 @@ func TestFilterKnownChanIDsZombieRevival(t *testing.T) {
 
 	// Mark channel 1 and 2 as zombies.
 	err := graph.MarkEdgeZombie(
-		ctx, lnwire.GossipVersion1, scid1.ToUint64(),
-		[33]byte{}, [33]byte{},
+		ctx, scid1.ToUint64(), [33]byte{}, [33]byte{},
 	)
 	require.NoError(t, err)
 	err = graph.MarkEdgeZombie(
-		ctx, lnwire.GossipVersion1, scid2.ToUint64(),
-		[33]byte{}, [33]byte{},
+		ctx, scid2.ToUint64(), [33]byte{}, [33]byte{},
 	)
 	require.NoError(t, err)
 

graph/db/kv_store.go

@@ -4174,8 +4174,9 @@ func (c *KVStore) FetchChannelEdgesByID(_ context.Context,
 	return edgeInfo, policy1, policy2, nil
 }
 
-// FetchChannelEdgesByIDPreferHighest looks up the channel by ID. The KV store
-// only supports gossip v1, so this simply delegates to the versioned fetch.
+// FetchChannelEdgesByIDPreferHighest looks up the channel by SCID. The KV
+// store only supports gossip v1, so this simply delegates to the versioned
+// fetch.
 //
 // NOTE: part of the Store interface.
 func (c *KVStore) FetchChannelEdgesByIDPreferHighest(ctx context.Context,

graph/db/sql_store.go

@@ -3871,9 +3871,27 @@ func (s *sqlNodeTraverser) ForEachNodeDirectedChannel(
 	ctx context.Context, nodePub route.Vertex,
 	cb func(channel *DirectedChannel) error, _ func()) error {
 
-	return forEachNodeDirectedChannel(
-		ctx, s.db, lnwire.GossipVersion1, nodePub, cb,
-	)
+	// Iterate across all gossip versions (highest first) so that
+	// channels announced via v2 are preferred over v1.
+	seen := make(map[uint64]struct{})
+	for _, v := range []lnwire.GossipVersion{gossipV2, gossipV1} {
+		err := forEachNodeDirectedChannel(
+			ctx, s.db, v, nodePub,
+			func(channel *DirectedChannel) error {
+				if _, ok := seen[channel.ChannelID]; ok {
+					return nil
+				}
+				seen[channel.ChannelID] = struct{}{}
+
+				return cb(channel)
+			},
+		)
+		if err != nil {
+			return err
+		}
+	}
+
+	return nil
 }
 
 // FetchNodeFeatures returns the features of the given node. If the node is