chore: use WaitGroup in dualStackDialContext

component/dialer/dialer.go

@@ -169,10 +169,15 @@ func dualStackDialContext(ctx context.Context, dialFn dialFunc, network string,
 	preferIPVersion := opt.prefer
 	fallbackTicker := time.NewTicker(fallbackTimeout)
 	defer fallbackTicker.Stop()
+
 	results := make(chan dialResult)
 	returned := make(chan struct{})
 	defer close(returned)
+
+	var wg sync.WaitGroup
+
 	racer := func(ips []netip.Addr, isPrimary bool) {
+		defer wg.Done()
 		result := dialResult{isPrimary: isPrimary}
 		defer func() {
 			select {
@@ -186,27 +191,35 @@ func dualStackDialContext(ctx context.Context, dialFn dialFunc, network string,
 		result.Conn, result.error = dialFn(ctx, network, ips, port, opt)
 	}
 
-	var wait int
 	if len(ipv4s) != 0 {
-		wait++
+		wg.Add(1)
 		go racer(ipv4s, preferIPVersion != 6)
 	}
 
 	if len(ipv6s) != 0 {
-		wait++
+		wg.Add(1)
 		go racer(ipv6s, preferIPVersion != 4)
 	}
 
+	go func() {
+		wg.Wait()
+		close(results)
+	}()
+
 	var fallback dialResult
 	var errs []error
-	for i := 0; i < wait; {
+
+loop:
+	for {
 		select {
 		case <-fallbackTicker.C:
 			if fallback.error == nil && fallback.Conn != nil {
 				return fallback.Conn, nil
 			}
-		case res := <-results:
+		case res, ok := <-results:
-			i++
+			if !ok {
+				break loop
+			}
 			if res.error == nil {
 				if res.isPrimary {
 					return res.Conn, nil
@@ -221,6 +234,7 @@ func dualStackDialContext(ctx context.Context, dialFn dialFunc, network string,
 			}
 		}
 	}
+
 	if fallback.error == nil && fallback.Conn != nil {
 		return fallback.Conn, nil
 	}