[iOS] Dispose of log readers and port forwarders if launch fails

packages/flutter_tools/lib/src/ios/devices.dart

@@ -523,6 +523,7 @@ class IOSDevice extends Device {
         _logger.printError('Try launching Xcode and selecting "Product > Run" to fix the problem:');
         _logger.printError('  open ios/Runner.xcworkspace');
         _logger.printError('');
+        await dispose();
         return LaunchResult.failed();
       }
 
@@ -557,6 +558,7 @@ class IOSDevice extends Device {
         final Uri? serviceURL = await vmServiceDiscovery?.uri;
         if (serviceURL == null) {
           await iosDeployDebugger?.stopAndDumpBacktrace();
+          await dispose();
           return LaunchResult.failed();
         }
 
@@ -587,12 +589,14 @@ class IOSDevice extends Device {
       timer.cancel();
       if (localUri == null) {
         await iosDeployDebugger?.stopAndDumpBacktrace();
+        await dispose();
         return LaunchResult.failed();
       }
       return LaunchResult.succeeded(vmServiceUri: localUri);
     } on ProcessException catch (e) {
       await iosDeployDebugger?.stopAndDumpBacktrace();
       _logger.printError(e.message);
+      await dispose();
       return LaunchResult.failed();
     } finally {
       startAppStatus.stop();

packages/flutter_tools/lib/src/ios/ios_deploy.dart

@@ -314,6 +314,7 @@ class IOSDeployDebugger {
 
   // Send signal to stop (pause) the app. Used before a backtrace dump.
   static const String _signalStop = 'process signal SIGSTOP';
+  static const String _signalStopError = 'Failed to send signal 17';
 
   static const String _processResume = 'process continue';
   static const String _processInterrupt = 'process interrupt';
@@ -401,11 +402,23 @@ class IOSDeployDebugger {
           }
           return;
         }
-        if (line == _signalStop) {
+
+        // (lldb) process signal SIGSTOP
+        // or
+        // process signal SIGSTOP
+        if (line.contains(_signalStop)) {
           // The app is about to be stopped. Only show in verbose mode.
           _logger.printTrace(line);
           return;
         }
+
+        // error: Failed to send signal 17: failed to send signal 17
+        if (line.contains(_signalStopError)) {
+          // The stop signal failed, force exit.
+          exit();
+          return;
+        }
+
         if (line == _backTraceAll) {
           // The app is stopped and the backtrace for all threads will be printed.
           _logger.printTrace(line);

packages/flutter_tools/test/general.shard/ios/ios_deploy_test.dart

@@ -11,6 +11,7 @@ import 'package:flutter_tools/src/artifacts.dart';
 import 'package:flutter_tools/src/base/file_system.dart';
 import 'package:flutter_tools/src/base/logger.dart';
 import 'package:flutter_tools/src/base/platform.dart';
+import 'package:flutter_tools/src/base/process.dart';
 import 'package:flutter_tools/src/cache.dart';
 import 'package:flutter_tools/src/device.dart';
 import 'package:flutter_tools/src/ios/ios_deploy.dart';
@@ -147,6 +148,28 @@ void main () {
         expect(logger.traceText, contains('* thread #1'));
       });
 
+      testWithoutContext('debugger attached and stop failed', () async {
+        final StreamController<List<int>> stdin = StreamController<List<int>>();
+        final FakeProcessManager processManager = FakeProcessManager.list(<FakeCommand>[
+          FakeCommand(
+            command: const <String>['ios-deploy'],
+            stdout: '(lldb)     run\r\nsuccess\r\nsuccess\r\nprocess signal SIGSTOP\r\n\r\nerror: Failed to send signal 17: failed to send signal 17',
+            stdin: IOSink(stdin.sink),
+          ),
+        ]);
+        final IOSDeployDebuggerWaitForExit iosDeployDebugger = IOSDeployDebuggerWaitForExit.test(
+          processManager: processManager,
+          logger: logger,
+        );
+
+        expect(iosDeployDebugger.logLines, emitsInOrder(<String>[
+          'success',
+        ]));
+
+        expect(await iosDeployDebugger.launchAndAttach(), isTrue);
+        await iosDeployDebugger.exitCompleter.future;
+      });
+
       testWithoutContext('handle processing logging after process exit', () async {
         final StreamController<List<int>> stdin = StreamController<List<int>>();
         // Make sure we don't hit a race where logging processed after the process exits
@@ -591,3 +614,37 @@ IOSDeploy setUpIOSDeploy(ProcessManager processManager, {
     cache: cache,
   );
 }
+
+class IOSDeployDebuggerWaitForExit extends IOSDeployDebugger {
+  IOSDeployDebuggerWaitForExit({
+    required super.logger,
+    required super.processUtils,
+    required super.launchCommand,
+    required super.iosDeployEnv
+  });
+
+  /// Create a [IOSDeployDebugger] for testing.
+  ///
+  /// Sets the command to "ios-deploy" and environment to an empty map.
+  factory IOSDeployDebuggerWaitForExit.test({
+    required ProcessManager processManager,
+    Logger? logger,
+  }) {
+    final Logger debugLogger = logger ?? BufferLogger.test();
+    return IOSDeployDebuggerWaitForExit(
+      logger: debugLogger,
+      processUtils: ProcessUtils(logger: debugLogger, processManager: processManager),
+      launchCommand: <String>['ios-deploy'],
+      iosDeployEnv: <String, String>{},
+    );
+  }
+
+  final Completer<void> exitCompleter = Completer<void>();
+
+  @override
+  bool exit() {
+    final bool status = super.exit();
+    exitCompleter.complete();
+    return status;
+  }
+}

packages/flutter_tools/test/general.shard/ios/ios_device_start_prebuilt_test.dart

@@ -67,6 +67,7 @@ const FakeCommand kLaunchDebugCommand = FakeCommand(command: <String>[
 // The command used to actually launch the app and attach the debugger with args in debug.
 FakeCommand attachDebuggerCommand({
   IOSink? stdin,
+  String stdout = '(lldb)     run\nsuccess',
   Completer<void>? completer,
   bool isWirelessDevice = false,
 }) {
@@ -94,7 +95,7 @@ FakeCommand attachDebuggerCommand({
       'PATH': '/usr/bin:null',
       'DYLD_LIBRARY_PATH': '/path/to/libraries',
     },
-    stdout: '(lldb)     run\nsuccess',
+    stdout: stdout,
     stdin: stdin,
   );
 }
@@ -156,6 +157,54 @@ void main() {
     expect(await device.stopApp(iosApp), false);
   });
 
+  testWithoutContext('IOSDevice.startApp twice in a row where ios-deploy fails the first time', () async {
+    final BufferLogger logger = BufferLogger.test();
+    final FileSystem fileSystem = MemoryFileSystem.test();
+    final Completer<void> completer = Completer<void>();
+    final FakeProcessManager processManager = FakeProcessManager.list(<FakeCommand>[
+      attachDebuggerCommand(
+        stdout: 'PROCESS_EXITED',
+      ),
+      attachDebuggerCommand(
+        stdout: '(lldb)     run\nsuccess\nThe Dart VM service is listening on http://127.0.0.1:456',
+        completer: completer,
+      ),
+    ]);
+    final IOSDevice device = setUpIOSDevice(
+      processManager: processManager,
+      fileSystem: fileSystem,
+      logger: logger,
+    );
+    final IOSApp iosApp = PrebuiltIOSApp(
+      projectBundleId: 'app',
+      bundleName: 'Runner',
+      uncompressedBundle: fileSystem.currentDirectory,
+      applicationPackage: fileSystem.currentDirectory,
+    );
+
+    device.portForwarder = const NoOpDevicePortForwarder();
+
+    final LaunchResult launchResult = await device.startApp(iosApp,
+      prebuiltApplication: true,
+      debuggingOptions: DebuggingOptions.enabled(BuildInfo.debug),
+      platformArgs: <String, dynamic>{},
+    );
+
+    expect(launchResult.started, false);
+    expect(launchResult.hasVmService, false);
+
+    final LaunchResult secondLaunchResult = await device.startApp(iosApp,
+      prebuiltApplication: true,
+      debuggingOptions: DebuggingOptions.enabled(BuildInfo.debug),
+      platformArgs: <String, dynamic>{},
+      discoveryTimeout: Duration.zero,
+    );
+    completer.complete();
+    expect(secondLaunchResult.started, true);
+    expect(secondLaunchResult.hasVmService, true);
+    expect(await device.stopApp(iosApp), false);
+  });
+
   testWithoutContext('IOSDevice.startApp launches in debug mode via log reading on <iOS 13', () async {
     final FileSystem fileSystem = MemoryFileSystem.test();
     final FakeProcessManager processManager = FakeProcessManager.list(<FakeCommand>[