graph/db: version channelCache by gossip version

Add a channelCacheKey struct keyed by {GossipVersion, chanID}, matching
the pattern already used by rejectCache. This prevents v1 and v2
channel data from colliding in the shared cache.

All callers in KVStore (always GossipVersion1) and SQLStore (version
from context) are updated to pass the version parameter.

This will be needed for later on when we update methods that use this
cache to be versioned (like ChannelUpdatesInHorizon).

graph/db/sql_store.go

@@ -750,7 +750,9 @@ func (s *SQLStore) AddChannelEdge(ctx context.Context,
 				s.rejectCache.remove(
 					edge.Version, edge.ChannelID,
 				)
-				s.chanCache.remove(edge.ChannelID)
+				s.chanCache.remove(
+					edge.Version, edge.ChannelID,
+				)
 
 				return nil
 			}
@@ -883,13 +885,13 @@ func (s *SQLStore) updateEdgeCache(e *models.ChannelEdgePolicy,
 	// the entry with the updated policy for the direction that was just
 	// written. If the edge doesn't exist, we'll defer loading the info and
 	// policies and lazily read from disk during the next query.
-	if channel, ok := s.chanCache.get(e.ChannelID); ok {
+	if channel, ok := s.chanCache.get(e.Version, e.ChannelID); ok {
 		if isUpdate1 {
 			channel.Policy1 = e
 		} else {
 			channel.Policy2 = e
 		}
-		s.chanCache.insert(e.ChannelID, channel)
+		s.chanCache.insert(e.Version, e.ChannelID, channel)
 	}
 }
 
@@ -1120,7 +1122,9 @@ func (s *SQLStore) buildChannelFromRow(ctx context.Context, db SQLQueries,
 
 // updateChanCacheBatch updates the channel cache with multiple edges at once.
 // This method acquires the cache lock only once for the entire batch.
-func (s *SQLStore) updateChanCacheBatch(edgesToCache map[uint64]ChannelEdge) {
+func (s *SQLStore) updateChanCacheBatch(v lnwire.GossipVersion,
+	edgesToCache map[uint64]ChannelEdge) {
+
 	if len(edgesToCache) == 0 {
 		return
 	}
@@ -1129,7 +1133,7 @@ func (s *SQLStore) updateChanCacheBatch(edgesToCache map[uint64]ChannelEdge) {
 	defer s.cacheMu.Unlock()
 
 	for chanID, edge := range edgesToCache {
-		s.chanCache.insert(chanID, edge)
+		s.chanCache.insert(v, chanID, edge)
 	}
 }
 
@@ -1232,6 +1236,7 @@ func (s *SQLStore) ChanUpdatesInHorizon(startTime, endTime time.Time,
 						// Check cache (we already hold
 						// shared read lock).
 						channel, ok := s.chanCache.get(
+							lnwire.GossipVersion1,
 							chanIDInt,
 						)
 						if ok {
@@ -1287,7 +1292,9 @@ func (s *SQLStore) ChanUpdatesInHorizon(startTime, endTime time.Time,
 
 			// Update cache after successful batch yield, setting
 			// the cache lock only once for the entire batch.
-			s.updateChanCacheBatch(edgesToCache)
+			s.updateChanCacheBatch(
+				lnwire.GossipVersion1, edgesToCache,
+			)
 			edgesToCache = make(map[uint64]ChannelEdge)
 
 			// If the batch didn't yield anything, then we're done.
@@ -1779,7 +1786,7 @@ func (s *SQLStore) MarkEdgeZombie(chanID uint64,
 	}
 
 	s.rejectCache.remove(lnwire.GossipVersion1, chanID)
-	s.chanCache.remove(chanID)
+	s.chanCache.remove(lnwire.GossipVersion1, chanID)
 
 	return nil
 }
@@ -1828,7 +1835,7 @@ func (s *SQLStore) MarkEdgeLive(chanID uint64) error {
 	}
 
 	s.rejectCache.remove(lnwire.GossipVersion1, chanID)
-	s.chanCache.remove(chanID)
+	s.chanCache.remove(lnwire.GossipVersion1, chanID)
 
 	return err
 }
@@ -2010,7 +2017,7 @@ func (s *SQLStore) DeleteChannelEdges(v lnwire.GossipVersion,
 
 	for _, chanID := range chanIDs {
 		s.rejectCache.remove(v, chanID)
-		s.chanCache.remove(chanID)
+		s.chanCache.remove(v, chanID)
 	}
 
 	return edges, nil
@@ -2901,7 +2908,7 @@ func (s *SQLStore) PruneGraph(spentOutputs []*wire.OutPoint,
 
 	for _, channel := range closedChans {
 		s.rejectCache.remove(channel.Version, channel.ChannelID)
-		s.chanCache.remove(channel.ChannelID)
+		s.chanCache.remove(channel.Version, channel.ChannelID)
 	}
 
 	return closedChans, prunedNodes, nil
@@ -3170,7 +3177,7 @@ func (s *SQLStore) DisconnectBlockAtHeight(height uint32) (
 	s.cacheMu.Lock()
 	for _, channel := range removedChans {
 		s.rejectCache.remove(channel.Version, channel.ChannelID)
-		s.chanCache.remove(channel.ChannelID)
+		s.chanCache.remove(channel.Version, channel.ChannelID)
 	}
 	s.cacheMu.Unlock()