basichost: ensure no duplicates in Addrs output (#2980)

p2p/host/basic/basic_host.go

@@ -500,13 +500,17 @@ func (h *BasicHost) makeUpdatedAddrEvent(prev, current []ma.Multiaddr) *event.Ev
 		return nil
 	}
 	prevmap := make(map[string]ma.Multiaddr, len(prev))
+	currmap := make(map[string]ma.Multiaddr, len(current))
 	evt := &event.EvtLocalAddressesUpdated{Diffs: true}
 	addrsAdded := false
 
 	for _, addr := range prev {
 		prevmap[string(addr.Bytes())] = addr
 	}
 	for _, addr := range current {
+		currmap[string(addr.Bytes())] = addr
+	}
+	for _, addr := range currmap {
 		_, ok := prevmap[string(addr.Bytes())]
 		updated := event.UpdatedAddress{Address: addr}
 		if ok {
@@ -831,7 +835,7 @@ func (h *BasicHost) Addrs() []ma.Multiaddr {
 	// Make a copy. Consumers can modify the slice elements
 	res := make([]ma.Multiaddr, len(addrs))
 	copy(res, addrs)
-	return res
+	return ma.Unique(res)
 }
 
 // NormalizeMultiaddr returns a multiaddr suitable for equality checks.

p2p/host/basic/basic_host_test.go

@@ -10,6 +10,7 @@ import (
 	"testing"
 	"time"
 
+	"github.com/libp2p/go-libp2p-testing/race"
 	"github.com/libp2p/go-libp2p/core/event"
 	"github.com/libp2p/go-libp2p/core/host"
 	"github.com/libp2p/go-libp2p/core/network"
@@ -248,6 +249,63 @@ func TestAllAddrs(t *testing.T) {
 	require.True(t, ma.Contains(h.AllAddrs(), firstAddr), "should still contain the original addr")
 }
 
+func TestAllAddrsUnique(t *testing.T) {
+	if race.WithRace() {
+		t.Skip("updates addrChangeTickrInterval which might be racy")
+	}
+	oldInterval := addrChangeTickrInterval
+	addrChangeTickrInterval = 100 * time.Millisecond
+	defer func() {
+		addrChangeTickrInterval = oldInterval
+	}()
+	sendNewAddrs := make(chan struct{})
+	opts := HostOpts{
+		AddrsFactory: func(addrs []ma.Multiaddr) []ma.Multiaddr {
+			select {
+			case <-sendNewAddrs:
+				return []ma.Multiaddr{
+					ma.StringCast("/ip4/1.2.3.4/tcp/1"),
+					ma.StringCast("/ip4/1.2.3.4/tcp/1"),
+					ma.StringCast("/ip4/1.2.3.4/tcp/1"),
+					ma.StringCast("/ip4/1.2.3.4/udp/1/quic-v1"),
+					ma.StringCast("/ip4/1.2.3.4/udp/1/quic-v1"),
+				}
+			default:
+				return nil
+			}
+		},
+	}
+	// no listen addrs
+	h, err := NewHost(swarmt.GenSwarm(t, swarmt.OptDialOnly), &opts)
+	require.NoError(t, err)
+	defer h.Close()
+	h.Start()
+
+	sub, err := h.EventBus().Subscribe(&event.EvtLocalAddressesUpdated{})
+	require.NoError(t, err)
+	out := make(chan int)
+	done := make(chan struct{})
+	go func() {
+		cnt := 0
+		for {
+			select {
+			case <-sub.Out():
+				cnt++
+			case <-done:
+				out <- cnt
+				return
+			}
+		}
+	}()
+	close(sendNewAddrs)
+	require.Len(t, h.Addrs(), 2)
+	require.ElementsMatch(t, []ma.Multiaddr{ma.StringCast("/ip4/1.2.3.4/tcp/1"), ma.StringCast("/ip4/1.2.3.4/udp/1/quic-v1")}, h.Addrs())
+	time.Sleep(2*addrChangeTickrInterval + 1*time.Second) // the background loop runs every 5 seconds. Wait for 2x that time.
+	close(done)
+	cnt := <-out
+	require.Equal(t, 1, cnt)
+}
+
 // getHostPair gets a new pair of hosts.
 // The first host initiates the connection to the second host.
 func getHostPair(t *testing.T) (host.Host, host.Host) {