Handle empty adb mdns service lists

Author: LinDevHard

internal/adb/adb.go

@@ -18,6 +18,8 @@ import (
 // ADB Wi-Fi mDNS/reconnect improvements described as ADB Wi-Fi 2.
 const Wifi2PlatformToolsMajor = 37
 
+const mdnsServicesHeader = "List of discovered mdns services"
+
 var platformToolsVersionRE = regexp.MustCompile(`(?m)^Version\s+([0-9]+)(?:\.[0-9]+)*`)
 
 type VersionInfo struct {
@@ -128,6 +130,18 @@ func MDNSServices(ctx context.Context, adbPath string) (string, error) {
 	return combined, nil
 }
 
+func ParseMDNSServices(raw string) []string {
+	var services []string
+	for _, line := range strings.Split(raw, "\n") {
+		line = strings.TrimSpace(line)
+		if line == "" || line == mdnsServicesHeader {
+			continue
+		}
+		services = append(services, line)
+	}
+	return services
+}
+
 // StartServer ensures the adb daemon is running. Without this the first
 // `adb pair` call sometimes hangs on daemon startup before the mDNS
 // announce window closes.

internal/adb/adb_test.go

@@ -81,3 +81,28 @@ func TestParseVersionWithoutPlatformToolsVersion(t *testing.T) {
 		t.Fatalf("SupportsWifi2Improvements = true, want false")
 	}
 }
+
+func TestParseMDNSServicesHeaderOnly(t *testing.T) {
+	got := ParseMDNSServices("List of discovered mdns services\n")
+	if len(got) != 0 {
+		t.Fatalf("ParseMDNSServices returned %v, want empty", got)
+	}
+}
+
+func TestParseMDNSServices(t *testing.T) {
+	raw := "List of discovered mdns services\nadb-123._adb-tls-connect._tcp.\t192.168.1.10:37123\n\nstudio-abc._adb-tls-pairing._tcp.\t192.168.1.10:45555"
+
+	got := ParseMDNSServices(raw)
+	want := []string{
+		"adb-123._adb-tls-connect._tcp.\t192.168.1.10:37123",
+		"studio-abc._adb-tls-pairing._tcp.\t192.168.1.10:45555",
+	}
+	if len(got) != len(want) {
+		t.Fatalf("len(ParseMDNSServices) = %d, want %d: %v", len(got), len(want), got)
+	}
+	for i := range want {
+		if got[i] != want[i] {
+			t.Fatalf("ParseMDNSServices[%d] = %q, want %q", i, got[i], want[i])
+		}
+	}
+}

main.go

@@ -110,13 +110,14 @@ func doctor(verbose bool) error {
 		fmt.Println("hint: if pairing hangs, check same Wi-Fi, AP isolation, firewall rules, and UDP 5353.")
 		return nil
 	}
-	if services == "" {
+	serviceLines := adb.ParseMDNSServices(services)
+	if len(serviceLines) == 0 {
 		fmt.Println("mDNS services: none reported by adb")
 		fmt.Println("hint: this is normal when no Android device is advertising Wireless debugging right now.")
 		return nil
 	}
 	fmt.Println("mDNS services:")
-	fmt.Println(services)
+	fmt.Println(strings.Join(serviceLines, "\n"))
 	return nil
 }