From 81fe6e73ed0f6b9148ce483caa223ebbd25bcb06 Mon Sep 17 00:00:00 2001
From: "Johan T. Halseth" <johanth@gmail.com>
Date: Tue, 4 Dec 2018 11:20:38 +0100
Subject: [PATCH] router+graph: return ErrGraphNodesNotFound if no nodes to
 prune

Avoids creating a bucket unneccessarily.
---
 channeldb/graph.go | 6 +++---
 routing/router.go  | 3 ++-
 2 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/channeldb/graph.go b/channeldb/graph.go
index 21680eb4a..7cf7f8987 100644
--- a/channeldb/graph.go
+++ b/channeldb/graph.go
@@ -795,9 +795,9 @@ func (c *ChannelGraph) PruneGraph(spentOutputs []*wire.OutPoint,
 // node gains more channels, it will be re-added back to the graph.
 func (c *ChannelGraph) PruneGraphNodes() error {
 	return c.db.Update(func(tx *bbolt.Tx) error {
-		nodes, err := tx.CreateBucketIfNotExists(nodeBucket)
-		if err != nil {
-			return err
+		nodes := tx.Bucket(nodeBucket)
+		if nodes == nil {
+			return ErrGraphNodesNotFound
 		}
 		edges := tx.Bucket(edgeBucket)
 		if edges == nil {
diff --git a/routing/router.go b/routing/router.go
index 0e1a9b269..d815592fe 100644
--- a/routing/router.go
+++ b/routing/router.go
@@ -445,7 +445,8 @@ func (r *ChannelRouter) Start() error {
 	// Finally, before we proceed, we'll prune any unconnected nodes from
 	// the graph in order to ensure we maintain a tight graph of "useful"
 	// nodes.
-	if err := r.cfg.Graph.PruneGraphNodes(); err != nil {
+	err = r.cfg.Graph.PruneGraphNodes()
+	if err != nil && err != channeldb.ErrGraphNodesNotFound {
 		return err
 	}