autopilot: pass pubkey in channel traversal

diff --git a/autopilot/graph.go b/autopilot/graph.go
index d82cdd3..19bd380 100644
--- a/autopilot/graph.go
+++ b/autopilot/graph.go
@@ -101,14 +101,14 @@ func (d *databaseChannelGraph) ForEachNode(ctx context.Context,
 	}, reset)
 }
 
-// ForEachNodesChannels iterates through all connected nodes, and for each node,
-// all the channels that connect to it. The passed callback will be called with
-// the context, the Node itself, and a slice of ChannelEdge that connect to the
-// node.
+// ForEachNodesChannels iterates through all connected nodes, and for each
+// node, all the channels that connect to it. The passed callback will be
+// called with the context, the node's pubkey, and a slice of ChannelEdge
+// that connect to the node.
 //
 // NOTE: Part of the autopilot.ChannelGraph interface.
 func (d *databaseChannelGraph) ForEachNodesChannels(ctx context.Context,
-	cb func(context.Context, Node, []*ChannelEdge) error,
+	cb func(context.Context, NodeID, []*ChannelEdge) error,
 	reset func()) error {
 
 	// The channel-scoring callers only need topology data here. Address
@@ -117,6 +117,10 @@ func (d *databaseChannelGraph) ForEachNodesChannels(ctx context.Context,
 		ctx, func(ctx context.Context, node route.Vertex,
 			chans map[uint64]*graphdb.DirectedChannel) error {
 
+			if len(chans) == 0 {
+				return nil
+			}
+
 			edges := make([]*ChannelEdge, 0, len(chans))
 			for _, channel := range chans {
 				edges = append(edges, &ChannelEdge{
@@ -128,9 +132,7 @@ func (d *databaseChannelGraph) ForEachNodesChannels(ctx context.Context,
 				})
 			}
 
-			return cb(ctx, &dbNode{
-				pub: node,
-			}, edges)
+			return cb(ctx, NodeID(node), edges)
 		}, reset,
 	)
 }
@@ -206,20 +208,24 @@ func (dc *databaseChannelGraphCached) ForEachNode(ctx context.Context,
 	}, reset)
 }
 
-// ForEachNodesChannels iterates through all connected nodes, and for each node,
-// all the channels that connect to it. The passed callback will be called with
-// the context, the Node itself, and a slice of ChannelEdge that connect to the
-// node.
+// ForEachNodesChannels iterates through all connected nodes, and for each
+// node, all the channels that connect to it. The passed callback will be
+// called with the context, the node's pubkey, and a slice of ChannelEdge
+// that connect to the node.
 //
 // NOTE: Part of the autopilot.ChannelGraph interface.
 func (dc *databaseChannelGraphCached) ForEachNodesChannels(ctx context.Context,
-	cb func(context.Context, Node, []*ChannelEdge) error,
+	cb func(context.Context, NodeID, []*ChannelEdge) error,
 	reset func()) error {
 
 	return dc.db.ForEachNodeCached(ctx, func(ctx context.Context,
 		n route.Vertex,
 		channels map[uint64]*graphdb.DirectedChannel) error {
 
+		if len(channels) == 0 {
+			return nil
+		}
+
 		edges := make([]*ChannelEdge, 0, len(channels))
 		for cid, channel := range channels {
 			edges = append(edges, &ChannelEdge{
@@ -229,18 +235,7 @@ func (dc *databaseChannelGraphCached) ForEachNodesChannels(ctx context.Context,
 			})
 		}
 
-		if len(channels) > 0 {
-			node := dbNodeCached{
-				node:     n,
-				channels: channels,
-			}
-
-			if err := cb(ctx, node, edges); err != nil {
-				return err
-			}
-		}
-
-		return nil
+		return cb(ctx, NodeID(n), edges)
 	}, reset)
 }
 
diff --git a/autopilot/interface.go b/autopilot/interface.go
index b3fc3de..7181323 100644
--- a/autopilot/interface.go
+++ b/autopilot/interface.go
@@ -84,10 +84,10 @@ type ChannelGraph interface {
 
 	// ForEachNodesChannels iterates through all connected nodes, and for
 	// each node, all the channels that connect to it. The passed callback
-	// will be called with the context, the Node itself, and a slice of
+	// will be called with the context, the node's pubkey, and a slice of
 	// ChannelEdge that connect to the node.
 	ForEachNodesChannels(ctx context.Context,
-		cb func(context.Context, Node, []*ChannelEdge) error,
+		cb func(context.Context, NodeID, []*ChannelEdge) error,
 		reset func()) error
 }
 
diff --git a/autopilot/prefattach.go b/autopilot/prefattach.go
index 267c13d..7d36674 100644
--- a/autopilot/prefattach.go
+++ b/autopilot/prefattach.go
@@ -90,7 +90,7 @@ func (p *PrefAttachment) NodeScores(ctx context.Context, g ChannelGraph,
 		seenChans = make(map[uint64]struct{})
 	)
 	err := g.ForEachNodesChannels(
-		ctx, func(_ context.Context, node Node,
+		ctx, func(_ context.Context, node NodeID,
 			channels []*ChannelEdge) error {
 
 			for _, e := range channels {
@@ -121,7 +121,7 @@ func (p *PrefAttachment) NodeScores(ctx context.Context, g ChannelGraph,
 	var maxChans int
 	nodeChanNum := make(map[NodeID]int)
 	err = g.ForEachNodesChannels(
-		ctx, func(ctx context.Context, node Node,
+		ctx, func(ctx context.Context, node NodeID,
 			edges []*ChannelEdge) error {
 
 			var nodeChans int
@@ -154,17 +154,16 @@ func (p *PrefAttachment) NodeScores(ctx context.Context, g ChannelGraph,
 
 			// If this node is not among our nodes to score, we can
 			// return early.
-			nID := NodeID(node.PubKey())
-			if _, ok := nodes[nID]; !ok {
+			if _, ok := nodes[node]; !ok {
 				log.Tracef("Node %x not among nodes to score, "+
-					"ignoring", nID[:])
+					"ignoring", node[:])
 				return nil
 			}
 
 			// Otherwise we'll record the number of channels.
-			nodeChanNum[nID] = nodeChans
+			nodeChanNum[node] = nodeChans
 			log.Tracef("Counted %v channels for node %x", nodeChans,
-				nID[:])
+				node[:])
 
 			return nil
 		}, func() {
diff --git a/autopilot/prefattach_test.go b/autopilot/prefattach_test.go
index efddfb8..cdaec87 100644
--- a/autopilot/prefattach_test.go
+++ b/autopilot/prefattach_test.go
@@ -246,11 +246,11 @@ func TestPrefAttachmentSelectGreedyAllocation(t *testing.T) {
 			twoChans := false
 			nodes := make(map[NodeID]struct{})
 			err = graph.ForEachNodesChannels(
-				ctx, func(_ context.Context, node Node,
+				ctx, func(_ context.Context, node NodeID,
 					edges []*ChannelEdge) error {
 
 					numNodes++
-					nodes[node.PubKey()] = struct{}{}
+					nodes[node] = struct{}{}
 					numChans := 0
 
 					for range edges {
@@ -619,14 +619,15 @@ func (m *memChannelGraph) ForEachNode(ctx context.Context,
 	return nil
 }
 
-// ForEachNodesChannels iterates through all connected nodes, and for each node,
-// all the channels that connect to it. The passed callback will be called with
-// the context, the Node itself, and a slice of ChannelEdge that connect to the
-// node.
+// ForEachNodesChannels iterates through all connected nodes, and for each
+// node, all the channels that connect to it. The passed callback will be
+// called with the context, the node's pubkey, and a slice of ChannelEdge
+// that connect to the node.
 //
 // NOTE: Part of the autopilot.ChannelGraph interface.
 func (m *memChannelGraph) ForEachNodesChannels(ctx context.Context,
-	cb func(context.Context, Node, []*ChannelEdge) error, _ func()) error {
+	cb func(context.Context, NodeID, []*ChannelEdge) error,
+	_ func()) error {
 
 	for _, node := range m.graph {
 		edges := make([]*ChannelEdge, 0, len(node.chans))
@@ -634,7 +635,7 @@ func (m *memChannelGraph) ForEachNodesChannels(ctx context.Context,
 			edges = append(edges, &node.chans[i])
 		}
 
-		if err := cb(ctx, node, edges); err != nil {
+		if err := cb(ctx, NewNodeID(node.pub), edges); err != nil {
 			return err
 		}
 	}
diff --git a/autopilot/simple_graph.go b/autopilot/simple_graph.go
index 44f5149..d6072cd 100644
--- a/autopilot/simple_graph.go
+++ b/autopilot/simple_graph.go
@@ -2,8 +2,6 @@ package autopilot
 
 import (
 	"context"
-
-	"github.com/lightningnetwork/lnd/routing/route"
 )
 
 // diameterCutoff is used to discard nodes in the diameter calculation.
@@ -35,12 +33,11 @@ func NewSimpleGraph(ctx context.Context, g ChannelGraph) (*SimpleGraph, error) {
 	// The returned index is then used to create a simplified adjacency list
 	// where each node is identified by its index instead of its pubkey, and
 	// also to create a mapping from node index to node pubkey.
-	getNodeIndex := func(node route.Vertex) int {
-		key := NodeID(node)
-		nodeIndex, ok := nodes[key]
+	getNodeIndex := func(node NodeID) int {
+		nodeIndex, ok := nodes[node]
 
 		if !ok {
-			nodes[key] = nextIndex
+			nodes[node] = nextIndex
 			nodeIndex = nextIndex
 			nextIndex++
 		}
@@ -51,12 +48,12 @@ func NewSimpleGraph(ctx context.Context, g ChannelGraph) (*SimpleGraph, error) {
 	// Iterate over each node and each channel and update the adj and the
 	// node index.
 	err := g.ForEachNodesChannels(ctx, func(_ context.Context,
-		node Node, channels []*ChannelEdge) error {
+		node NodeID, channels []*ChannelEdge) error {
 
-		u := getNodeIndex(node.PubKey())
+		u := getNodeIndex(node)
 
 		for _, edge := range channels {
-			v := getNodeIndex(edge.Peer)
+			v := getNodeIndex(NodeID(edge.Peer))
 			adj[u] = append(adj[u], v)
 		}