[flutter_tool] Observatory connection error handling cleanup (#38353)

packages/flutter_tools/lib/src/commands/attach.dart

@@ -243,6 +243,8 @@ class AttachCommand extends FlutterCommand {
           // Determine ipv6 status from the scanned logs.
           usesIpv6 = observatoryDiscovery.ipv6;
           printStatus('Done.'); // FYI, this message is used as a sentinel in tests.
+        } catch (error) {
+          throwToolExit('Failed to establish a debug connection with ${device.name}: $error');
         } finally {
           await observatoryDiscovery?.cancel();
         }

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

@@ -152,9 +152,9 @@ class IOSDevice extends Device {
   @override
   final String name;
 
-  Map<ApplicationPackage, _IOSDeviceLogReader> _logReaders;
+  Map<ApplicationPackage, DeviceLogReader> _logReaders;
 
-  _IOSDevicePortForwarder _portForwarder;
+  DevicePortForwarder _portForwarder;
 
   @override
   Future<bool> get isLocalEmulator async => false;
@@ -342,65 +342,55 @@ class IOSDevice extends Device {
     if (platformArgs['trace-startup'] ?? false)
       launchArguments.add('--trace-startup');
 
-    int installationResult = -1;
-    Uri localObservatoryUri;
-
-    final Status installStatus = logger.startProgress('Installing and launching...', timeout: timeoutConfiguration.slowOperation);
-
-    if (!debuggingOptions.debuggingEnabled) {
-      // If debugging is not enabled, just launch the application and continue.
-      printTrace('Debugging is not enabled');
-      installationResult = await const IOSDeploy().runApp(
-        deviceId: id,
-        bundlePath: bundle.path,
-        launchArguments: launchArguments,
-      );
-    } else {
-      // Debugging is enabled, look for the observatory server port post launch.
-      printTrace('Debugging is enabled, connecting to observatory');
-
-      // TODO(danrubel): The Android device class does something similar to this code below.
-      // The various Device subclasses should be refactored and common code moved into the superclass.
-      final ProtocolDiscovery observatoryDiscovery = ProtocolDiscovery.observatory(
-        getLogReader(app: package),
-        portForwarder: portForwarder,
-        hostPort: debuggingOptions.observatoryPort,
-        ipv6: ipv6,
-      );
-
-      final Future<Uri> forwardObservatoryUri = observatoryDiscovery.uri;
+    final Status installStatus = logger.startProgress(
+        'Installing and launching...',
+        timeout: timeoutConfiguration.slowOperation);
+    try {
+      ProtocolDiscovery observatoryDiscovery;
+      if (debuggingOptions.debuggingEnabled) {
+        // Debugging is enabled, look for the observatory server port post launch.
+        printTrace('Debugging is enabled, connecting to observatory');
+
+        // TODO(danrubel): The Android device class does something similar to this code below.
+        // The various Device subclasses should be refactored and common code moved into the superclass.
+        observatoryDiscovery = ProtocolDiscovery.observatory(
+          getLogReader(app: package),
+          portForwarder: portForwarder,
+          hostPort: debuggingOptions.observatoryPort,
+          ipv6: ipv6,
+        );
+      }
 
-      final Future<int> launch = const IOSDeploy().runApp(
+      final int installationResult = await const IOSDeploy().runApp(
         deviceId: id,
         bundlePath: bundle.path,
         launchArguments: launchArguments,
       );
+      if (installationResult != 0) {
+        printError('Could not install ${bundle.path} on $id.');
+        printError('Try launching Xcode and selecting "Product > Run" to fix the problem:');
+        printError('  open ios/Runner.xcworkspace');
+        printError('');
+        return LaunchResult.failed();
+      }
 
-      localObservatoryUri = await launch.then<Uri>((int result) async {
-        installationResult = result;
-
-        if (result != 0) {
-          printTrace('Failed to launch the application on device.');
-          return null;
-        }
+      if (!debuggingOptions.debuggingEnabled) {
+        return LaunchResult.succeeded();
+      }
 
+      try {
         printTrace('Application launched on the device. Waiting for observatory port.');
-        return await forwardObservatoryUri;
-      }).whenComplete(() {
-        observatoryDiscovery.cancel();
-      });
-    }
-    installStatus.stop();
-
-    if (installationResult != 0) {
-      printError('Could not install ${bundle.path} on $id.');
-      printError('Try launching Xcode and selecting "Product > Run" to fix the problem:');
-      printError('  open ios/Runner.xcworkspace');
-      printError('');
-      return LaunchResult.failed();
+        final Uri localUri = await observatoryDiscovery.uri;
+        return LaunchResult.succeeded(observatoryUri: localUri);
+      } catch (error) {
+        printError('Failed to establish a debug connection with $id: $error');
+        return LaunchResult.failed();
+      } finally {
+        await observatoryDiscovery?.cancel();
+      }
+    } finally {
+      installStatus.stop();
     }
-
-    return LaunchResult.succeeded(observatoryUri: localObservatoryUri);
   }
 
   @override
@@ -417,13 +407,24 @@ class IOSDevice extends Device {
 
   @override
   DeviceLogReader getLogReader({ ApplicationPackage app }) {
-    _logReaders ??= <ApplicationPackage, _IOSDeviceLogReader>{};
+    _logReaders ??= <ApplicationPackage, DeviceLogReader>{};
     return _logReaders.putIfAbsent(app, () => _IOSDeviceLogReader(this, app));
   }
 
+  @visibleForTesting
+  void setLogReader(ApplicationPackage app, DeviceLogReader logReader) {
+    _logReaders ??= <ApplicationPackage, DeviceLogReader>{};
+    _logReaders[app] = logReader;
+  }
+
   @override
   DevicePortForwarder get portForwarder => _portForwarder ??= _IOSDevicePortForwarder(this);
 
+  @visibleForTesting
+  set portForwarder(DevicePortForwarder forwarder) {
+    _portForwarder = forwarder;
+  }
+
   @override
   void clearLogs() { }
 

packages/flutter_tools/lib/src/protocol_discovery.dart

@@ -65,9 +65,9 @@ class ProtocolDiscovery {
     if (match != null) {
       try {
         uri = Uri.parse(match[1]);
-      } catch (error) {
+      } catch (error, stackTrace) {
         _stopScrapingLogs();
-        _completer.completeError(error);
+        _completer.completeError(error, stackTrace);
       }
     }
 

packages/flutter_tools/test/general.shard/commands/attach_test.dart

@@ -52,15 +52,6 @@ void main() {
         mockLogReader = MockDeviceLogReader();
         portForwarder = MockPortForwarder();
         device = MockAndroidDevice();
-        when(device.getLogReader()).thenAnswer((_) {
-          // Now that the reader is used, start writing messages to it.
-          Timer.run(() {
-            mockLogReader.addLine('Foo');
-            mockLogReader.addLine('Observatory listening on http://127.0.0.1:$devicePort');
-          });
-
-          return mockLogReader;
-        });
         when(device.portForwarder)
           .thenReturn(portForwarder);
         when(portForwarder.forward(devicePort, hostPort: anyNamed('hostPort')))
@@ -82,6 +73,14 @@ void main() {
       });
 
       testUsingContext('finds observatory port and forwards', () async {
+        when(device.getLogReader()).thenAnswer((_) {
+          // Now that the reader is used, start writing messages to it.
+          Timer.run(() {
+            mockLogReader.addLine('Foo');
+            mockLogReader.addLine('Observatory listening on http://127.0.0.1:$devicePort');
+          });
+          return mockLogReader;
+        });
         testDeviceManager.addDevice(device);
         final Completer<void> completer = Completer<void>();
         final StreamSubscription<String> loggerSubscription = logger.stream.listen((String message) {
@@ -102,7 +101,32 @@ void main() {
         Logger: () => logger,
       });
 
+      testUsingContext('Fails with tool exit on bad Observatory uri', () async {
+        when(device.getLogReader()).thenAnswer((_) {
+          // Now that the reader is used, start writing messages to it.
+          Timer.run(() {
+            mockLogReader.addLine('Foo');
+            mockLogReader.addLine('Observatory listening on http:/:/127.0.0.1:$devicePort');
+          });
+          return mockLogReader;
+        });
+        testDeviceManager.addDevice(device);
+        expect(createTestCommandRunner(AttachCommand()).run(<String>['attach']),
+               throwsA(isA<ToolExit>()));
+      }, overrides: <Type, Generator>{
+        FileSystem: () => testFileSystem,
+        Logger: () => logger,
+      });
+
       testUsingContext('accepts filesystem parameters', () async {
+        when(device.getLogReader()).thenAnswer((_) {
+          // Now that the reader is used, start writing messages to it.
+          Timer.run(() {
+            mockLogReader.addLine('Foo');
+            mockLogReader.addLine('Observatory listening on http://127.0.0.1:$devicePort');
+          });
+          return mockLogReader;
+        });
         testDeviceManager.addDevice(device);
 
         const String filesystemScheme = 'foo';
@@ -175,6 +199,14 @@ void main() {
       });
 
       testUsingContext('exits when ipv6 is specified and debug-port is not', () async {
+        when(device.getLogReader()).thenAnswer((_) {
+          // Now that the reader is used, start writing messages to it.
+          Timer.run(() {
+            mockLogReader.addLine('Foo');
+            mockLogReader.addLine('Observatory listening on http://127.0.0.1:$devicePort');
+          });
+          return mockLogReader;
+        });
         testDeviceManager.addDevice(device);
 
         final AttachCommand command = AttachCommand();
@@ -190,6 +222,14 @@ void main() {
       },);
 
       testUsingContext('exits when observatory-port is specified and debug-port is not', () async {
+        when(device.getLogReader()).thenAnswer((_) {
+          // Now that the reader is used, start writing messages to it.
+          Timer.run(() {
+            mockLogReader.addLine('Foo');
+            mockLogReader.addLine('Observatory listening on http://127.0.0.1:$devicePort');
+          });
+          return mockLogReader;
+        });
         testDeviceManager.addDevice(device);
 
         final AttachCommand command = AttachCommand();

packages/flutter_tools/test/src/mocks.dart

@@ -153,7 +153,7 @@ ro.build.version.codename=REL
 typedef ProcessFactory = Process Function(List<String> command);
 
 /// A ProcessManager that starts Processes by delegating to a ProcessFactory.
-class MockProcessManager implements ProcessManager {
+class MockProcessManager extends Mock implements ProcessManager {
   ProcessFactory processFactory = (List<String> commands) => MockProcess();
   bool canRunSucceeds = true;
   bool runSucceeds = true;
@@ -180,9 +180,6 @@ class MockProcessManager implements ProcessManager {
     commands = command;
     return Future<Process>.value(processFactory(command));
   }
-
-  @override
-  dynamic noSuchMethod(Invocation invocation) => null;
 }
 
 /// A process that exits successfully with no output and ignores all input.