[flutter_tools] Fix null check errors in attach command (#107864)

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

@@ -215,7 +215,11 @@ known, it can be explicitly provided to attach via the command-line, e.g.
   Future<FlutterCommandResult> runCommand() async {
     await _validateArguments();
 
-    final Device device = await (findTargetDevice() as FutureOr<Device>);
+    final Device? device = await findTargetDevice();
+
+    if (device == null) {
+      throwToolExit('Did not find any valid target devices.');
+    }
 
     final Artifacts? overrideArtifacts = device.artifactOverrides ?? globals.artifacts;
     await context.run<void>(
@@ -272,7 +276,7 @@ known, it can be explicitly provided to attach via the command-line, e.g.
       } else if ((device is IOSDevice) || (device is IOSSimulator) || (device is MacOSDesignedForIPadDevice)) {
         final Uri? uriFromMdns =
           await MDnsObservatoryDiscovery.instance!.getObservatoryUri(
-            appId!,
+            appId,
             device,
             usesIpv6: usesIpv6,
             deviceVmservicePort: deviceVmservicePort,
@@ -317,12 +321,12 @@ known, it can be explicitly provided to attach via the command-line, e.g.
     try {
       int? result;
       if (daemon != null) {
-        final ResidentRunner runner = await (createResidentRunner(
+        final ResidentRunner runner = await createResidentRunner(
           observatoryUris: observatoryUri,
           device: device,
           flutterProject: flutterProject,
           usesIpv6: usesIpv6,
-        ) as FutureOr<ResidentRunner>);
+        );
         late AppInstance app;
         try {
           app = await daemon.appDomain.launch(
@@ -351,12 +355,12 @@ known, it can be explicitly provided to attach via the command-line, e.g.
         return;
       }
       while (true) {
-        final ResidentRunner runner = await (createResidentRunner(
+        final ResidentRunner runner = await createResidentRunner(
           observatoryUris: observatoryUri,
           device: device,
           flutterProject: flutterProject,
           usesIpv6: usesIpv6,
-        ) as FutureOr<ResidentRunner>);
+        );
         final Completer<void> onAppStart = Completer<void>.sync();
         TerminalHandler? terminalHandler;
         unawaited(onAppStart.future.whenComplete(() {
@@ -400,7 +404,7 @@ known, it can be explicitly provided to attach via the command-line, e.g.
     }
   }
 
-  Future<ResidentRunner?> createResidentRunner({
+  Future<ResidentRunner> createResidentRunner({
     required Stream<Uri> observatoryUris,
     required Device device,
     required FlutterProject flutterProject,
@@ -452,7 +456,7 @@ known, it can be explicitly provided to attach via the command-line, e.g.
 }
 
 class HotRunnerFactory {
-  HotRunner? build(
+  HotRunner build(
     List<FlutterDevice> devices, {
     required String target,
     required DebuggingOptions debuggingOptions,

packages/flutter_tools/lib/src/mdns_discovery.dart

@@ -145,7 +145,7 @@ class MDnsObservatoryDiscovery {
     }
   }
 
-  Future<Uri?> getObservatoryUri(String applicationId, Device device, {
+  Future<Uri?> getObservatoryUri(String? applicationId, Device device, {
     bool usesIpv6 = false,
     int? hostVmservicePort,
     int? deviceVmservicePort,

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

@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @dart = 2.8
-
 import 'dart:async';
 
 import 'package:file/memory.dart';
@@ -13,6 +11,7 @@ import 'package:flutter_tools/src/artifacts.dart';
 import 'package:flutter_tools/src/base/common.dart';
 import 'package:flutter_tools/src/base/dds.dart';
 import 'package:flutter_tools/src/base/file_system.dart';
+import 'package:flutter_tools/src/base/io.dart';
 import 'package:flutter_tools/src/base/logger.dart';
 import 'package:flutter_tools/src/base/terminal.dart';
 import 'package:flutter_tools/src/build_info.dart';
@@ -24,11 +23,13 @@ import 'package:flutter_tools/src/globals.dart' as globals;
 import 'package:flutter_tools/src/ios/application_package.dart';
 import 'package:flutter_tools/src/ios/devices.dart';
 import 'package:flutter_tools/src/macos/macos_ipad_device.dart';
+import 'package:flutter_tools/src/mdns_discovery.dart';
 import 'package:flutter_tools/src/project.dart';
+import 'package:flutter_tools/src/reporting/reporting.dart';
 import 'package:flutter_tools/src/resident_runner.dart';
 import 'package:flutter_tools/src/run_hot.dart';
 import 'package:flutter_tools/src/vmservice.dart';
-import 'package:meta/meta.dart';
+import 'package:multicast_dns/multicast_dns.dart';
 import 'package:test/fake.dart';
 import 'package:vm_service/vm_service.dart' as vm_service;
 
@@ -43,8 +44,8 @@ void main() {
   });
 
   group('attach', () {
-    StreamLogger logger;
-    FileSystem testFileSystem;
+    late StreamLogger logger;
+    late FileSystem testFileSystem;
 
     setUp(() {
       Cache.disableLocking();
@@ -62,10 +63,10 @@ void main() {
       const int devicePort = 499;
       const int hostPort = 42;
 
-      FakeDeviceLogReader fakeLogReader;
-      RecordingPortForwarder portForwarder;
-      FakeDartDevelopmentService fakeDds;
-      FakeAndroidDevice device;
+      late FakeDeviceLogReader fakeLogReader;
+      late RecordingPortForwarder portForwarder;
+      late FakeDartDevelopmentService fakeDds;
+      late FakeAndroidDevice device;
 
       setUp(() {
         fakeLogReader = FakeDeviceLogReader();
@@ -80,6 +81,45 @@ void main() {
         fakeLogReader.dispose();
       });
 
+      testUsingContext('succeeds with iOS device', () async {
+        final FakeIOSDevice device = FakeIOSDevice(
+          logReader: fakeLogReader,
+          portForwarder: portForwarder,
+          onGetLogReader: () {
+            fakeLogReader.addLine('Foo');
+            fakeLogReader.addLine('The Dart VM service is listening on http://127.0.0.1:$devicePort');
+            return fakeLogReader;
+          },
+        );
+
+        testDeviceManager.addDevice(device);
+        final Completer<void> completer = Completer<void>();
+        final StreamSubscription<String> loggerSubscription = logger.stream.listen((String message) {
+          if (message == '[verbose] Observatory URL on device: http://127.0.0.1:$devicePort') {
+            // The "Observatory URL on device" message is output by the ProtocolDiscovery when it found the observatory.
+            completer.complete();
+          }
+        });
+        final Future<void> task = createTestCommandRunner(AttachCommand()).run(<String>['attach']);
+        await completer.future;
+
+        expect(portForwarder.devicePort, devicePort);
+        expect(portForwarder.hostPort, hostPort);
+
+        await fakeLogReader.dispose();
+        await expectLoggerInterruptEndsTask(task, logger);
+        await loggerSubscription.cancel();
+      }, overrides: <Type, Generator>{
+        FileSystem: () => testFileSystem,
+        ProcessManager: () => FakeProcessManager.any(),
+        Logger: () => logger,
+        MDnsObservatoryDiscovery: () => MDnsObservatoryDiscovery(
+          mdnsClient: FakeMDnsClient(<PtrResourceRecord>[], <String, List<SrvResourceRecord>>{}),
+          logger: logger,
+          flutterUsage: TestUsage(),
+        ),
+      });
+
       testUsingContext('finds observatory port and forwards', () async {
         device.onGetLogReader = () {
           fakeLogReader.addLine('Foo');
@@ -139,8 +179,8 @@ void main() {
 
         final FakeHotRunner hotRunner = FakeHotRunner();
         hotRunner.onAttach = (
-          Completer<DebugConnectionInfo> connectionInfoCompleter,
-          Completer<void> appStartedCompleter,
+          Completer<DebugConnectionInfo>? connectionInfoCompleter,
+          Completer<void>? appStartedCompleter,
           bool allowExistingDdsInstance,
           bool enableDevTools,
         ) async => 0;
@@ -224,8 +264,8 @@ void main() {
     group('forwarding to given port', () {
       const int devicePort = 499;
       const int hostPort = 42;
-      RecordingPortForwarder portForwarder;
-      FakeAndroidDevice device;
+      late RecordingPortForwarder portForwarder;
+      late FakeAndroidDevice device;
 
       setUp(() {
         final FakeDartDevelopmentService fakeDds = FakeDartDevelopmentService();
@@ -408,8 +448,8 @@ void main() {
       final FakeHotRunnerFactory hotRunnerFactory = FakeHotRunnerFactory()
         ..hotRunner = hotRunner;
       hotRunner.onAttach = (
-        Completer<DebugConnectionInfo> connectionInfoCompleter,
-        Completer<void> appStartedCompleter,
+        Completer<DebugConnectionInfo>? connectionInfoCompleter,
+        Completer<void>? appStartedCompleter,
         bool allowExistingDdsInstance,
         bool enableDevTools,
       ) async {
@@ -438,8 +478,8 @@ void main() {
         ..hotRunner = hotRunner;
 
       hotRunner.onAttach = (
-        Completer<DebugConnectionInfo> connectionInfoCompleter,
-        Completer<void> appStartedCompleter,
+        Completer<DebugConnectionInfo>? connectionInfoCompleter,
+        Completer<void>? appStartedCompleter,
         bool allowExistingDdsInstance,
         bool enableDevTools,
       ) async {
@@ -447,7 +487,6 @@ void main() {
         throw vm_service.RPCError('flutter._listViews', RPCErrorCodes.kInvalidParams, '');
       };
 
-
       testDeviceManager.addDevice(device);
       testFileSystem.file('lib/main.dart').createSync();
 
@@ -463,7 +502,7 @@ void main() {
 }
 
 class FakeHotRunner extends Fake implements HotRunner {
-  Future<int> Function(Completer<DebugConnectionInfo>, Completer<void>, bool, bool) onAttach;
+  late Future<int> Function(Completer<DebugConnectionInfo>?, Completer<void>?, bool, bool) onAttach;
 
   @override
   bool exited = false;
@@ -473,8 +512,8 @@ class FakeHotRunner extends Fake implements HotRunner {
 
   @override
   Future<int> attach({
-    Completer<DebugConnectionInfo> connectionInfoCompleter,
-    Completer<void> appStartedCompleter,
+    Completer<DebugConnectionInfo>? connectionInfoCompleter,
+    Completer<void>? appStartedCompleter,
     bool allowExistingDdsInstance = false,
     bool enableDevTools = false,
     bool needsFullRestart = true,
@@ -484,25 +523,25 @@ class FakeHotRunner extends Fake implements HotRunner {
 }
 
 class FakeHotRunnerFactory extends Fake implements HotRunnerFactory {
-  HotRunner hotRunner;
-  String dillOutputPath;
-  String projectRootPath;
-  List<FlutterDevice> devices;
+  late HotRunner hotRunner;
+  String? dillOutputPath;
+  String? projectRootPath;
+  late List<FlutterDevice> devices;
 
   @override
   HotRunner build(
     List<FlutterDevice> devices, {
-    String target,
-    DebuggingOptions debuggingOptions,
+    required String target,
+    required DebuggingOptions debuggingOptions,
     bool benchmarkMode = false,
-    File applicationBinary,
+    File? applicationBinary,
     bool hostIsIde = false,
-    String projectRootPath,
-    String packagesFilePath,
-    String dillOutputPath,
+    String? projectRootPath,
+    String? packagesFilePath,
+    String? dillOutputPath,
     bool stayResident = true,
     bool ipv6 = false,
-    FlutterProject flutterProject,
+    FlutterProject? flutterProject,
   }) {
     this.devices = devices;
     this.dillOutputPath = dillOutputPath;
@@ -514,17 +553,17 @@ class FakeHotRunnerFactory extends Fake implements HotRunnerFactory {
 class RecordingPortForwarder implements DevicePortForwarder {
   RecordingPortForwarder([this.hostPort]);
 
-  int devicePort;
-  int hostPort;
+  int? devicePort;
+  int? hostPort;
 
   @override
   Future<void> dispose() async { }
 
   @override
-  Future<int> forward(int devicePort, {int hostPort}) async {
+  Future<int> forward(int devicePort, {int? hostPort}) async {
     this.devicePort = devicePort;
     this.hostPort ??= hostPort;
-    return this.hostPort;
+    return this.hostPort!;
   }
 
   @override
@@ -541,12 +580,12 @@ class StreamLogger extends Logger {
   @override
   void printError(
     String message, {
-    StackTrace stackTrace,
-    bool emphasis,
-    TerminalColor color,
-    int indent,
-    int hangingIndent,
-    bool wrap,
+    StackTrace? stackTrace,
+    bool? emphasis,
+    TerminalColor? color,
+    int? indent,
+    int? hangingIndent,
+    bool? wrap,
   }) {
     hadErrorOutput = true;
     _log('[stderr] $message');
@@ -555,11 +594,11 @@ class StreamLogger extends Logger {
   @override
   void printWarning(
     String message, {
-    bool emphasis,
-    TerminalColor color,
-    int indent,
-    int hangingIndent,
-    bool wrap,
+    bool? emphasis,
+    TerminalColor? color,
+    int? indent,
+    int? hangingIndent,
+    bool? wrap,
   }) {
     hadWarningOutput = true;
     _log('[stderr] $message');
@@ -568,12 +607,12 @@ class StreamLogger extends Logger {
   @override
   void printStatus(
     String message, {
-    bool emphasis,
-    TerminalColor color,
-    bool newline,
-    int indent,
-    int hangingIndent,
-    bool wrap,
+    bool? emphasis,
+    TerminalColor? color,
+    bool? newline,
+    int? indent,
+    int? hangingIndent,
+    bool? wrap,
   }) {
     _log('[stdout] $message');
   }
@@ -581,7 +620,7 @@ class StreamLogger extends Logger {
   @override
   void printBox(
     String message, {
-    String title,
+    String? title,
   }) {
     if (title == null) {
       _log('[stdout] $message');
@@ -598,8 +637,8 @@ class StreamLogger extends Logger {
   @override
   Status startProgress(
     String message, {
-    @required Duration timeout,
-    String progressId,
+    Duration? timeout,
+    String? progressId,
     bool multilineOutput = false,
     bool includeTiming = true,
     int progressIndicatorPadding = kDefaultStatusPadding,
@@ -612,9 +651,9 @@ class StreamLogger extends Logger {
 
   @override
   Status startSpinner({
-    VoidCallback onFinish,
-    Duration timeout,
-    SlowWarningCallback slowWarningCallback,
+    VoidCallback? onFinish,
+    Duration? timeout,
+    SlowWarningCallback? slowWarningCallback,
   }) {
     return SilentStatus(
       stopwatch: Stopwatch(),
@@ -641,7 +680,7 @@ class StreamLogger extends Logger {
   Stream<String> get stream => _controller.stream;
 
   @override
-  void sendEvent(String name, [Map<String, dynamic> args]) { }
+  void sendEvent(String name, [Map<String, dynamic>? args]) { }
 
   @override
   bool get supportsColor => throw UnimplementedError();
@@ -676,10 +715,10 @@ class FakeDartDevelopmentService extends Fake implements DartDevelopmentService
   @override
   Future<void> startDartDevelopmentService(
     Uri observatoryUri, {
-    @required Logger logger,
-    int hostPort,
-    bool ipv6,
-    bool disableServiceAuthCodes,
+    required Logger logger,
+    int? hostPort,
+    bool? ipv6,
+    bool? disableServiceAuthCodes,
     bool cacheStartupProfile = false,
   }) async {}
 
@@ -691,10 +730,10 @@ class FakeDartDevelopmentService extends Fake implements DartDevelopmentService
 // Until we fix that, we have to also ignore related lints here.
 // ignore: avoid_implementing_value_types
 class FakeAndroidDevice extends Fake implements AndroidDevice {
-  FakeAndroidDevice({@required this.id});
+  FakeAndroidDevice({required this.id});
 
   @override
-  DartDevelopmentService dds;
+  late DartDevelopmentService dds;
 
   @override
   final String id;
@@ -727,20 +766,25 @@ class FakeAndroidDevice extends Fake implements AndroidDevice {
   bool isSupportedForProject(FlutterProject flutterProject) => true;
 
   @override
-  DevicePortForwarder portForwarder;
+  DevicePortForwarder? portForwarder;
 
-  DeviceLogReader Function() onGetLogReader;
+  DeviceLogReader Function()? onGetLogReader;
 
   @override
   FutureOr<DeviceLogReader> getLogReader({
-    AndroidApk app,
+    AndroidApk? app,
     bool includePastLogs = false,
   }) {
-    return onGetLogReader();
+    if (onGetLogReader == null) {
+      throw UnimplementedError(
+        'Called getLogReader but no onGetLogReader callback was supplied in the constructor to FakeAndroidDevice.',
+      );
+    }
+    return onGetLogReader!();
   }
 
   @override
-  OverrideArtifacts get artifactOverrides => null;
+  OverrideArtifacts? get artifactOverrides => null;
 
   @override
   final PlatformType platformType = PlatformType.android;
@@ -753,24 +797,40 @@ class FakeAndroidDevice extends Fake implements AndroidDevice {
 // Until we fix that, we have to also ignore related lints here.
 // ignore: avoid_implementing_value_types
 class FakeIOSDevice extends Fake implements IOSDevice {
-  FakeIOSDevice({this.dds, this.portForwarder, this.logReader});
+  FakeIOSDevice({
+    DevicePortForwarder? portForwarder,
+    DeviceLogReader? logReader,
+    this.onGetLogReader,
+  }) : _portForwarder = portForwarder, _logReader = logReader;
+
+  final DevicePortForwarder? _portForwarder;
 
   @override
-  final DevicePortForwarder portForwarder;
+  DevicePortForwarder get portForwarder => _portForwarder!;
 
   @override
-  final DartDevelopmentService dds;
+  DartDevelopmentService get dds => throw UnimplementedError('getter dds not implemented');
+
+  final DeviceLogReader? _logReader;
+  DeviceLogReader get logReader => _logReader!;
 
-  final DeviceLogReader logReader;
+  final DeviceLogReader Function()? onGetLogReader;
 
   @override
   DeviceLogReader getLogReader({
-    IOSApp app,
+    IOSApp? app,
     bool includePastLogs = false,
-  }) => logReader;
+  }) {
+    if (onGetLogReader == null) {
+      throw UnimplementedError(
+        'Called getLogReader but no onGetLogReader callback was supplied in the constructor to FakeIOSDevice',
+      );
+    }
+    return onGetLogReader!();
+  }
 
   @override
-  OverrideArtifacts get artifactOverrides => null;
+  OverrideArtifacts? get artifactOverrides => null;
 
   @override
   final String name = 'name';
@@ -781,3 +841,49 @@ class FakeIOSDevice extends Fake implements IOSDevice {
   @override
   final PlatformType platformType = PlatformType.ios;
 }
+
+class FakeMDnsClient extends Fake implements MDnsClient {
+  FakeMDnsClient(this.ptrRecords, this.srvResponse, {
+    this.txtResponse = const <String, List<TxtResourceRecord>>{},
+    this.osErrorOnStart = false,
+  });
+
+  final List<PtrResourceRecord> ptrRecords;
+  final Map<String, List<SrvResourceRecord>> srvResponse;
+  final Map<String, List<TxtResourceRecord>> txtResponse;
+  final bool osErrorOnStart;
+
+  @override
+  Future<void> start({
+    InternetAddress? listenAddress,
+    NetworkInterfacesFactory? interfacesFactory,
+    int mDnsPort = 5353,
+    InternetAddress? mDnsAddress,
+  }) async {
+    if (osErrorOnStart) {
+      throw const OSError('Operation not supported on socket', 102);
+    }
+  }
+
+  @override
+  Stream<T> lookup<T extends ResourceRecord>(
+    ResourceRecordQuery query, {
+    Duration timeout = const Duration(seconds: 5),
+  }) {
+    if (T == PtrResourceRecord && query.fullyQualifiedName == MDnsObservatoryDiscovery.dartObservatoryName) {
+      return Stream<PtrResourceRecord>.fromIterable(ptrRecords) as Stream<T>;
+    }
+    if (T == SrvResourceRecord) {
+      final String key = query.fullyQualifiedName;
+      return Stream<SrvResourceRecord>.fromIterable(srvResponse[key] ?? <SrvResourceRecord>[]) as Stream<T>;
+    }
+    if (T == TxtResourceRecord) {
+      final String key = query.fullyQualifiedName;
+      return Stream<TxtResourceRecord>.fromIterable(txtResponse[key] ?? <TxtResourceRecord>[]) as Stream<T>;
+    }
+    throw UnsupportedError('Unsupported query type $T');
+  }
+
+  @override
+  void stop() {}
+}