From 9be85b6b4bf41df834c676d9feac20c0657ac812 Mon Sep 17 00:00:00 2001
From: Jakob Andersen <jakobr@google.com>
Date: Sat, 11 Nov 2017 21:33:40 +0100
Subject: [PATCH] Support IPv6-only hosts in vmservice_test.dart. (#12985)

If we fail to bind to IPv4 loopback, try IPv6. Some hosts only support IPv6,
causing the test in vmservice_test.dart to fail, since it couldn't find an
available port.
---
 packages/flutter_tools/lib/src/base/port_scanner.dart | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/packages/flutter_tools/lib/src/base/port_scanner.dart b/packages/flutter_tools/lib/src/base/port_scanner.dart
index 58af21ddcd..86cc401afd 100644
--- a/packages/flutter_tools/lib/src/base/port_scanner.dart
+++ b/packages/flutter_tools/lib/src/base/port_scanner.dart
@@ -61,7 +61,12 @@ class HostPortScanner extends PortScanner {
 
   @override
   Future<int> findAvailablePort() async {
-    final ServerSocket socket = await ServerSocket.bind(InternetAddress.LOOPBACK_IP_V4, 0);
+    ServerSocket socket;
+    try {
+      socket = await ServerSocket.bind(InternetAddress.LOOPBACK_IP_V4, 0);
+    } on SocketException {
+      socket = await ServerSocket.bind(InternetAddress.LOOPBACK_IP_V6, 0, v6Only: true);
+    }
     final int port = socket.port;
     await socket.close();
     return port;