multi: remove kvdb.RTx from ForEachNodeChannel

Since we have not removed all call-sites that make use of this
parameter, we can remove it. This helps hide DB-specific details from
the interface we will introduce for the graph store.

graph/builder.go

@@ -13,7 +13,6 @@ import (
 	"github.com/lightningnetwork/lnd/chainntnfs"
 	graphdb "github.com/lightningnetwork/lnd/graph/db"
 	"github.com/lightningnetwork/lnd/graph/db/models"
-	"github.com/lightningnetwork/lnd/kvdb"
 	"github.com/lightningnetwork/lnd/lnutils"
 	"github.com/lightningnetwork/lnd/lnwallet"
 	"github.com/lightningnetwork/lnd/lnwire"
@@ -1276,8 +1275,7 @@ func (b *Builder) ForAllOutgoingChannels(cb func(*models.ChannelEdgeInfo,
 	*models.ChannelEdgePolicy) error) error {
 
 	return b.cfg.Graph.ForEachNodeChannel(b.cfg.SelfNode,
-		func(_ kvdb.RTx, c *models.ChannelEdgeInfo,
-			e *models.ChannelEdgePolicy,
+		func(c *models.ChannelEdgeInfo, e *models.ChannelEdgePolicy,
 			_ *models.ChannelEdgePolicy) error {
 
 			if e == nil {

graph/db/graph_test.go

@@ -1141,7 +1141,7 @@ func TestGraphTraversal(t *testing.T) {
 	numNodeChans := 0
 	firstNode, secondNode := nodeList[0], nodeList[1]
 	err = graph.ForEachNodeChannel(firstNode.PubKeyBytes,
-		func(_ kvdb.RTx, _ *models.ChannelEdgeInfo, outEdge,
+		func(_ *models.ChannelEdgeInfo, outEdge,
 			inEdge *models.ChannelEdgePolicy) error {
 
 			// All channels between first and second node should
@@ -2882,7 +2882,7 @@ func TestIncompleteChannelPolicies(t *testing.T) {
 
 		calls := 0
 		err := graph.ForEachNodeChannel(node.PubKeyBytes,
-			func(_ kvdb.RTx, _ *models.ChannelEdgeInfo, outEdge,
+			func(_ *models.ChannelEdgeInfo, outEdge,
 				inEdge *models.ChannelEdgePolicy) error {
 
 				if !expectedOut && outEdge != nil {
@@ -4001,8 +4001,7 @@ func BenchmarkForEachChannel(b *testing.B) {
 		require.NoError(b, err)
 
 		for _, n := range nodes {
-			cb := func(tx kvdb.RTx,
-				info *models.ChannelEdgeInfo,
+			cb := func(info *models.ChannelEdgeInfo,
 				policy *models.ChannelEdgePolicy,
 				policy2 *models.ChannelEdgePolicy) error { //nolint:ll
 

graph/db/kv_store.go

@@ -3103,10 +3103,15 @@ func nodeTraversal(tx kvdb.RTx, nodePub []byte, db kvdb.Backend,
 //
 // Unknown policies are passed into the callback as nil values.
 func (c *KVStore) ForEachNodeChannel(nodePub route.Vertex,
-	cb func(kvdb.RTx, *models.ChannelEdgeInfo, *models.ChannelEdgePolicy,
+	cb func(*models.ChannelEdgeInfo, *models.ChannelEdgePolicy,
 		*models.ChannelEdgePolicy) error) error {
 
-	return nodeTraversal(nil, nodePub[:], c.db, cb)
+	return nodeTraversal(nil, nodePub[:], c.db, func(_ kvdb.RTx,
+		info *models.ChannelEdgeInfo, policy,
+		policy2 *models.ChannelEdgePolicy) error {
+
+		return cb(info, policy, policy2)
+	})
 }
 
 // ForEachSourceNodeChannel iterates through all channels of the source node,

graph/interfaces.go

@@ -8,7 +8,6 @@ import (
 	"github.com/lightningnetwork/lnd/batch"
 	graphdb "github.com/lightningnetwork/lnd/graph/db"
 	"github.com/lightningnetwork/lnd/graph/db/models"
-	"github.com/lightningnetwork/lnd/kvdb"
 	"github.com/lightningnetwork/lnd/lnwire"
 	"github.com/lightningnetwork/lnd/routing/route"
 )
@@ -254,10 +253,9 @@ type DB interface {
 	// to the caller.
 	//
 	// Unknown policies are passed into the callback as nil values.
-	ForEachNodeChannel(nodePub route.Vertex, cb func(kvdb.RTx,
-		*models.ChannelEdgeInfo,
-		*models.ChannelEdgePolicy,
-		*models.ChannelEdgePolicy) error) error
+	ForEachNodeChannel(nodePub route.Vertex,
+		cb func(*models.ChannelEdgeInfo, *models.ChannelEdgePolicy,
+			*models.ChannelEdgePolicy) error) error
 
 	// AddEdgeProof sets the proof of an existing edge in the graph
 	// database.