From 309d45acef795bbaa1bd1be595835a601e87b02c Mon Sep 17 00:00:00 2001
From: nisdas <nishdas93@gmail.com>
Date: Thu, 10 Sep 2020 16:24:14 +0800
Subject: [PATCH] copy string topic

---
 gossipsub.go      |  7 ++++++-
 gossipsub_test.go | 44 ++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 50 insertions(+), 1 deletion(-)

diff --git a/gossipsub.go b/gossipsub.go
index cf5f9b1..e1fdded 100644
--- a/gossipsub.go
+++ b/gossipsub.go
@@ -1550,7 +1550,12 @@ func (gs *GossipSubRouter) sendGraftPrune(tograft, toprune map[peer.ID][]string,
 	for p, topics := range tograft {
 		graft := make([]*pb.ControlGraft, 0, len(topics))
 		for _, topic := range topics {
-			graft = append(graft, &pb.ControlGraft{TopicID: &topic})
+			// copy topic string here since
+			// the reference to the string
+			// topic here changes with every
+			// iteration of the slice.
+			copiedID := topic
+			graft = append(graft, &pb.ControlGraft{TopicID: &copiedID})
 		}
 
 		var prune []*pb.ControlPrune
diff --git a/gossipsub_test.go b/gossipsub_test.go
index 6e56ee8..2f8d897 100644
--- a/gossipsub_test.go
+++ b/gossipsub_test.go
@@ -1567,6 +1567,50 @@ func TestGossipsubPiggybackControl(t *testing.T) {
 	}
 }
 
+func TestGossipsubMultipleGraftTopics(t *testing.T) {
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+	hosts := getNetHosts(t, ctx, 2)
+
+	psubs := getGossipsubs(ctx, hosts)
+
+	sparseConnect(t, hosts)
+
+	time.Sleep(time.Second * 1)
+
+	firstTopic := "topic1"
+	secondTopic := "topic2"
+	thirdTopic := "topic3"
+
+	firstPeer := hosts[0].ID()
+	secondPeer := hosts[1].ID()
+
+	p1Router := psubs[0].rt.(*GossipSubRouter)
+	p2Router := psubs[1].rt.(*GossipSubRouter)
+	// Add topics to second peer
+	p2Router.mesh[firstTopic] = map[peer.ID]struct{}{}
+	p2Router.mesh[secondTopic] = map[peer.ID]struct{}{}
+	p2Router.mesh[thirdTopic] = map[peer.ID]struct{}{}
+
+	// Send multiple GRAFT messages to second peer from
+	// 1st peer
+	p1Router.sendGraftPrune(map[peer.ID][]string{
+		secondPeer: []string{firstTopic, secondTopic, thirdTopic},
+	}, map[peer.ID][]string{}, map[peer.ID]bool{})
+
+	time.Sleep(time.Second * 1)
+
+	if _, ok := p2Router.mesh[firstTopic][firstPeer]; !ok {
+		t.Errorf("First peer wasnt added to mesh of the second peer for the topic %s", firstTopic)
+	}
+	if _, ok := p2Router.mesh[secondTopic][firstPeer]; !ok {
+		t.Errorf("First peer wasnt added to mesh of the second peer for the topic %s", secondTopic)
+	}
+	if _, ok := p2Router.mesh[thirdTopic][firstPeer]; !ok {
+		t.Errorf("First peer wasnt added to mesh of the second peer for the topic %s", thirdTopic)
+	}
+}
+
 func TestGossipsubOpportunisticGrafting(t *testing.T) {
 	originalGossipSubPruneBackoff := GossipSubPruneBackoff
 	GossipSubPruneBackoff = 500 * time.Millisecond