From ffe5851eb726d9798ce82ee5a8084c1bfb9752b9 Mon Sep 17 00:00:00 2001
From: Jason Simmons <jason-simmons@users.noreply.github.com>
Date: Thu, 3 Aug 2017 13:09:10 -0700
Subject: [PATCH] Do not throw if a hot reload is attempted when all Flutter
 instances on the device have been stopped (#11504)

This can happen if an Android host app has been paused but its process is still running
---
 packages/flutter_tools/lib/src/run_hot.dart | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/packages/flutter_tools/lib/src/run_hot.dart b/packages/flutter_tools/lib/src/run_hot.dart
index d800754aee..a4faac372f 100644
--- a/packages/flutter_tools/lib/src/run_hot.dart
+++ b/packages/flutter_tools/lib/src/run_hot.dart
@@ -467,16 +467,19 @@ class HotRunner extends ResidentRunner {
       final String entryPath = fs.path.relative(mainPath, from: projectRootPath);
       if (benchmarkMode)
         vmReloadTimer.start();
-      Map<String, dynamic> reloadReport;
-      final List<Future<Map<String, dynamic>>> reloadReports = <Future<Map<String, dynamic>>>[];
+      final List<Future<Map<String, dynamic>>> reloadReportFutures = <Future<Map<String, dynamic>>>[];
       for (FlutterDevice device in flutterDevices) {
         final List<Future<Map<String, dynamic>>> reports = device.reloadSources(
           entryPath,
           pause: pause
         );
-        reloadReports.addAll(reports);
+        reloadReportFutures.addAll(reports);
       }
-      reloadReport = (await Future.wait(reloadReports)).first;
+      if (reloadReportFutures.isEmpty) {
+        printError('Unable to hot reload. No instance of Flutter is currently running.');
+        return new OperationResult(1, 'No instances running');
+      }
+      final Map<String, dynamic> reloadReport = (await Future.wait(reloadReportFutures)).first;
 
       if (!validateReloadReport(reloadReport)) {
         // Reload failed.