graph/db: add version parameter to FetchChannelEdgesByID/Outpoint

diff --git a/graph/db/graph.go b/graph/db/graph.go
index 6c4b0a1..0f4dda6 100644
--- a/graph/db/graph.go
+++ b/graph/db/graph.go
@@ -711,7 +711,9 @@ func (c *ChannelGraph) FetchChannelEdgesByOutpoint(op *wire.OutPoint) (
 	*models.ChannelEdgeInfo, *models.ChannelEdgePolicy,
 	*models.ChannelEdgePolicy, error) {
 
-	return c.db.FetchChannelEdgesByOutpoint(op)
+	return c.db.FetchChannelEdgesByOutpoint(
+		lnwire.GossipVersion1, op,
+	)
 }
 
 // FetchChannelEdgesByID attempts to lookup directed edges by channel ID.
@@ -719,7 +721,9 @@ func (c *ChannelGraph) FetchChannelEdgesByID(chanID uint64) (
 	*models.ChannelEdgeInfo, *models.ChannelEdgePolicy,
 	*models.ChannelEdgePolicy, error) {
 
-	return c.db.FetchChannelEdgesByID(chanID)
+	return c.db.FetchChannelEdgesByID(
+		lnwire.GossipVersion1, chanID,
+	)
 }
 
 // ChannelView returns the verifiable edge information for each active channel.
@@ -785,6 +789,23 @@ func (c *VersionedGraph) FetchNode(ctx context.Context,
 	return c.db.FetchNode(ctx, c.v, nodePub)
 }
 
+// FetchChannelEdgesByID attempts to lookup directed edges by channel ID.
+func (c *VersionedGraph) FetchChannelEdgesByID(chanID uint64) (
+	*models.ChannelEdgeInfo, *models.ChannelEdgePolicy,
+	*models.ChannelEdgePolicy, error) {
+
+	return c.db.FetchChannelEdgesByID(c.v, chanID)
+}
+
+// FetchChannelEdgesByOutpoint attempts to lookup directed edges by funding
+// outpoint.
+func (c *VersionedGraph) FetchChannelEdgesByOutpoint(op *wire.OutPoint) (
+	*models.ChannelEdgeInfo, *models.ChannelEdgePolicy,
+	*models.ChannelEdgePolicy, error) {
+
+	return c.db.FetchChannelEdgesByOutpoint(c.v, op)
+}
+
 // AddrsForNode returns all known addresses for the target node public key.
 func (c *VersionedGraph) AddrsForNode(ctx context.Context,
 	nodePub *btcec.PublicKey) (bool, []net.Addr, error) {
diff --git a/graph/db/interfaces.go b/graph/db/interfaces.go
index 5658fa5..c684813 100644
--- a/graph/db/interfaces.go
+++ b/graph/db/interfaces.go
@@ -276,7 +276,7 @@ type Store interface { //nolint:interfacebloat
 	// houses the general information for the channel itself is returned as
 	// well as two structs that contain the routing policies for the channel
 	// in either direction.
-	FetchChannelEdgesByOutpoint(op *wire.OutPoint) (
+	FetchChannelEdgesByOutpoint(v lnwire.GossipVersion, op *wire.OutPoint) (
 		*models.ChannelEdgeInfo, *models.ChannelEdgePolicy,
 		*models.ChannelEdgePolicy, error)
 
@@ -291,7 +291,7 @@ type Store interface { //nolint:interfacebloat
 	// zombie within the database. In this case, the ChannelEdgePolicy's
 	// will be nil, and the ChannelEdgeInfo will only include the public
 	// keys of each node.
-	FetchChannelEdgesByID(chanID uint64) (
+	FetchChannelEdgesByID(v lnwire.GossipVersion, chanID uint64) (
 		*models.ChannelEdgeInfo, *models.ChannelEdgePolicy,
 		*models.ChannelEdgePolicy, error)
 
diff --git a/graph/db/kv_store.go b/graph/db/kv_store.go
index b3442bd..0887ff0 100644
--- a/graph/db/kv_store.go
+++ b/graph/db/kv_store.go
@@ -3811,8 +3811,8 @@ func computeEdgePolicyKeys(info *models.ChannelEdgeInfo) ([]byte, []byte) {
 // found, then ErrEdgeNotFound is returned. A struct which houses the general
 // information for the channel itself is returned as well as two structs that
 // contain the routing policies for the channel in either direction.
-func (c *KVStore) FetchChannelEdgesByOutpoint(op *wire.OutPoint) (
-	*models.ChannelEdgeInfo, *models.ChannelEdgePolicy,
+func (c *KVStore) FetchChannelEdgesByOutpoint(v lnwire.GossipVersion,
+	op *wire.OutPoint) (*models.ChannelEdgeInfo, *models.ChannelEdgePolicy,
 	*models.ChannelEdgePolicy, error) {
 
 	var (
@@ -3821,6 +3821,10 @@ func (c *KVStore) FetchChannelEdgesByOutpoint(op *wire.OutPoint) (
 		policy2  *models.ChannelEdgePolicy
 	)
 
+	if v != lnwire.GossipVersion1 {
+		return nil, nil, nil, ErrVersionNotSupportedForKVDB
+	}
+
 	err := kvdb.View(c.db, func(tx kvdb.RTx) error {
 		// First, grab the node bucket. This will be used to populate
 		// the Node pointers in each edge read from disk.
@@ -3897,10 +3901,14 @@ func (c *KVStore) FetchChannelEdgesByOutpoint(op *wire.OutPoint) (
 // ErrZombieEdge an be returned if the edge is currently marked as a zombie
 // within the database. In this case, the ChannelEdgePolicy's will be nil, and
 // the ChannelEdgeInfo will only include the public keys of each node.
-func (c *KVStore) FetchChannelEdgesByID(chanID uint64) (
-	*models.ChannelEdgeInfo, *models.ChannelEdgePolicy,
+func (c *KVStore) FetchChannelEdgesByID(v lnwire.GossipVersion,
+	chanID uint64) (*models.ChannelEdgeInfo, *models.ChannelEdgePolicy,
 	*models.ChannelEdgePolicy, error) {
 
+	if v != lnwire.GossipVersion1 {
+		return nil, nil, nil, ErrVersionNotSupportedForKVDB
+	}
+
 	var (
 		edgeInfo  *models.ChannelEdgeInfo
 		policy1   *models.ChannelEdgePolicy
diff --git a/graph/db/sql_store.go b/graph/db/sql_store.go
index 2f0b1c5..7cebede 100644
--- a/graph/db/sql_store.go
+++ b/graph/db/sql_store.go
@@ -2008,8 +2008,8 @@ func (s *SQLStore) DeleteChannelEdges(v lnwire.GossipVersion,
 // the ChannelEdgeInfo will only include the public keys of each node.
 //
 // NOTE: part of the Store interface.
-func (s *SQLStore) FetchChannelEdgesByID(chanID uint64) (
-	*models.ChannelEdgeInfo, *models.ChannelEdgePolicy,
+func (s *SQLStore) FetchChannelEdgesByID(v lnwire.GossipVersion,
+	chanID uint64) (*models.ChannelEdgeInfo, *models.ChannelEdgePolicy,
 	*models.ChannelEdgePolicy, error) {
 
 	var (
@@ -2018,11 +2018,18 @@ func (s *SQLStore) FetchChannelEdgesByID(chanID uint64) (
 		policy1, policy2 *models.ChannelEdgePolicy
 		chanIDB          = channelIDToBytes(chanID)
 	)
+
+	if !isKnownGossipVersion(v) {
+		return nil, nil, nil, fmt.Errorf(
+			"unsupported gossip version: %d", v,
+		)
+	}
+
 	err := s.db.ExecTx(ctx, sqldb.ReadTxOpt(), func(db SQLQueries) error {
 		row, err := db.GetChannelBySCIDWithPolicies(
 			ctx, sqlc.GetChannelBySCIDWithPoliciesParams{
 				Scid:    chanIDB,
-				Version: int16(lnwire.GossipVersion1),
+				Version: int16(v),
 			},
 		)
 		if errors.Is(err, sql.ErrNoRows) {
@@ -2031,7 +2038,7 @@ func (s *SQLStore) FetchChannelEdgesByID(chanID uint64) (
 			zombie, err := db.GetZombieChannel(
 				ctx, sqlc.GetZombieChannelParams{
 					Scid:    chanIDB,
-					Version: int16(lnwire.GossipVersion1),
+					Version: int16(v),
 				},
 			)
 			if errors.Is(err, sql.ErrNoRows) {
@@ -2118,8 +2125,8 @@ func (s *SQLStore) FetchChannelEdgesByID(chanID uint64) (
 // contain the routing policies for the channel in either direction.
 //
 // NOTE: part of the Store interface.
-func (s *SQLStore) FetchChannelEdgesByOutpoint(op *wire.OutPoint) (
-	*models.ChannelEdgeInfo, *models.ChannelEdgePolicy,
+func (s *SQLStore) FetchChannelEdgesByOutpoint(v lnwire.GossipVersion,
+	op *wire.OutPoint) (*models.ChannelEdgeInfo, *models.ChannelEdgePolicy,
 	*models.ChannelEdgePolicy, error) {
 
 	var (
@@ -2127,11 +2134,18 @@ func (s *SQLStore) FetchChannelEdgesByOutpoint(op *wire.OutPoint) (
 		edge             *models.ChannelEdgeInfo
 		policy1, policy2 *models.ChannelEdgePolicy
 	)
+
+	if !isKnownGossipVersion(v) {
+		return nil, nil, nil, fmt.Errorf(
+			"unsupported gossip version: %d", v,
+		)
+	}
+
 	err := s.db.ExecTx(ctx, sqldb.ReadTxOpt(), func(db SQLQueries) error {
 		row, err := db.GetChannelByOutpointWithPolicies(
 			ctx, sqlc.GetChannelByOutpointWithPoliciesParams{
 				Outpoint: op.String(),
-				Version:  int16(lnwire.GossipVersion1),
+				Version:  int16(v),
 			},
 		)
 		if errors.Is(err, sql.ErrNoRows) {
@@ -4662,6 +4676,21 @@ func getAndBuildChanPolicies(ctx context.Context, cfg *sqldb.QueryConfig,
 		return nil, nil, nil
 	}
 
+	// TODO(elle): update to support v2 policies.
+	if dbPol1 != nil &&
+		lnwire.GossipVersion(dbPol1.Version) != lnwire.GossipVersion1 {
+
+		return nil, nil, fmt.Errorf("unsupported policy1 version: %d",
+			dbPol1.Version)
+	}
+
+	if dbPol2 != nil &&
+		lnwire.GossipVersion(dbPol2.Version) != lnwire.GossipVersion1 {
+
+		return nil, nil, fmt.Errorf("unsupported policy2 version: %d",
+			dbPol2.Version)
+	}
+
 	var policyIDs = make([]int64, 0, 2)
 	if dbPol1 != nil {
 		policyIDs = append(policyIDs, dbPol1.ID)