From 8634c92c98cf6d5e03ed57d278b8a1118528a86c Mon Sep 17 00:00:00 2001
From: Steven Allen <steven@stebalien.com>
Date: Thu, 9 Apr 2020 18:40:31 -0700
Subject: [PATCH] fix: dedup addresses

---
 dual/dual.go      | 17 ++++++++++++++++-
 dual/dual_test.go |  8 ++++----
 2 files changed, 20 insertions(+), 5 deletions(-)

diff --git a/dual/dual.go b/dual/dual.go
index f60e6a92a..4df46c914 100644
--- a/dual/dual.go
+++ b/dual/dual.go
@@ -15,6 +15,8 @@ import (
 	dht "github.com/libp2p/go-libp2p-kad-dht"
 	helper "github.com/libp2p/go-libp2p-routing-helpers"
 
+	ma "github.com/multiformats/go-multiaddr"
+
 	"github.com/hashicorp/go-multierror"
 )
 
@@ -151,9 +153,22 @@ func (dht *DHT) FindPeer(ctx context.Context, pid peer.ID) (peer.AddrInfo, error
 
 	wg.Wait()
 
+	// combine addresses
+	deduped := make(map[string]ma.Multiaddr, len(wanInfo.Addrs)+len(lanInfo.Addrs))
+	for _, addr := range wanInfo.Addrs {
+		deduped[string(addr.Bytes())] = addr
+	}
+	for _, addr := range lanInfo.Addrs {
+		deduped[string(addr.Bytes())] = addr
+	}
+	addrs := make([]ma.Multiaddr, 0, len(deduped))
+	for _, addr := range deduped {
+		addrs = append(addrs, addr)
+	}
+
 	return peer.AddrInfo{
 		ID:    pid,
-		Addrs: append(wanInfo.Addrs, lanInfo.Addrs...),
+		Addrs: addrs,
 	}, multierror.Append(wanErr, lanErr).ErrorOrNil()
 }
 
diff --git a/dual/dual_test.go b/dual/dual_test.go
index 87349f3c8..dbd4aab12 100644
--- a/dual/dual_test.go
+++ b/dual/dual_test.go
@@ -356,14 +356,14 @@ func TestFindPeer(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
-	if len(p.Addrs) == 0 {
-		t.Fatal("expeced find peer to find addresses.")
+	if len(p.Addrs) != 1 {
+		t.Fatalf("expeced find peer to find 1 address, found %d", len(p.Addrs))
 	}
 	p, err = d.FindPeer(ctx, wan.PeerID())
 	if err != nil {
 		t.Fatal(err)
 	}
-	if len(p.Addrs) == 0 {
-		t.Fatal("expeced find peer to find addresses.")
+	if len(p.Addrs) != 1 {
+		t.Fatalf("expeced find peer to find addresses, found %d", len(p.Addrs))
 	}
 }