fix: deduplicate Swarm.Announce and AppendAnnounce

#8177 (comment)
#8177 (comment)

core/node/libp2p/addrs.go

@@ -26,22 +26,29 @@ func AddrFilters(filters []string) func() (*ma.Filters, Libp2pOpts, error) {
 }
 
 func makeAddrsFactory(announce []string, appendAnnouce []string, noAnnounce []string) (p2pbhost.AddrsFactory, error) {
-	var err error // To assign to the slice in the for loop
+	var err error                     // To assign to the slice in the for loop
+	existing := make(map[string]bool) // To avoid duplicates
 
 	annAddrs := make([]ma.Multiaddr, len(announce))
 	for i, addr := range announce {
 		annAddrs[i], err = ma.NewMultiaddr(addr)
 		if err != nil {
 			return nil, err
 		}
+		existing[addr] = true
 	}
 
-	appendAnnAddrs := make([]ma.Multiaddr, len(appendAnnouce))
-	for i, addr := range appendAnnouce {
-		appendAnnAddrs[i], err = ma.NewMultiaddr(addr)
+	var appendAnnAddrs []ma.Multiaddr
+	for _, addr := range appendAnnouce {
+		if existing[addr] {
+			// skip AppendAnnounce that is on the Announce list already
+			continue
+		}
+		appendAddr, err := ma.NewMultiaddr(addr)
 		if err != nil {
 			return nil, err
 		}
+		appendAnnAddrs = append(appendAnnAddrs, appendAddr)
 	}
 
 	filters := ma.NewFilters()

test/sharness/t0140-swarm.sh

@@ -65,9 +65,16 @@ test_expect_success 'Addresses.Announce affects addresses' '
 
 test_kill_ipfs_daemon
 
-announceCfg='["/dnsaddr/dynamic.example.com", "/ip4/10.20.30.40/tcp/4321"]'
-test_expect_success "test_config_set AppendAnnounce succeeds" "
-  ipfs config --json Addresses.AppendAnnounce '$announceCfg'
+
+announceCfg='["/ip4/127.0.0.1/tcp/4001", "/ip4/1.2.3.4/tcp/1234"]'
+test_expect_success "test_config_set succeeds" "
+  ipfs config --json Addresses.Announce '$announceCfg'
+"
+# Include "/ip4/1.2.3.4/tcp/1234" to ensure we deduplicate addrs already present in Swarm.Announce
+appendAnnounceCfg='["/dnsaddr/dynamic.example.com", "/ip4/10.20.30.40/tcp/4321", "/ip4/1.2.3.4/tcp/1234"]'
+test_expect_success "test_config_set Announce and AppendAnnounce succeeds" "
+  ipfs config --json Addresses.Announce '$announceCfg' &&
+  ipfs config --json Addresses.AppendAnnounce '$appendAnnounceCfg'
 "
 
 test_launch_ipfs_daemon