[flutter_tools] migrate web_device.dart to null-safety (#91632)

packages/flutter_tools/lib/src/android/android_device.dart

@@ -541,7 +541,7 @@ class AndroidDevice extends Device {
     String mainPath,
     String route,
     DebuggingOptions debuggingOptions,
-    Map<String, dynamic> platformArgs,
+    Map<String, dynamic> platformArgs = const <String, Object>{},
     bool prebuiltApplication = false,
     bool ipv6 = false,
     String userIdentifier,

packages/flutter_tools/lib/src/device.dart

@@ -468,7 +468,7 @@ abstract class Device {
   /// The ID returned matches that in the output of `flutter emulators`. Fetching
   /// this name may require connecting to the device and if an error occurs null
   /// will be returned.
-  Future<String> get emulatorId;
+  Future<String?> get emulatorId;
 
   /// Whether this device can run the provided [buildMode].
   ///
@@ -501,7 +501,7 @@ abstract class Device {
   /// Specify [userIdentifier] to install for a particular user (Android only).
   Future<bool> installApp(
     covariant ApplicationPackage app, {
-    String userIdentifier,
+    String? userIdentifier,
   });
 
   /// Uninstall an app package from the current device.
@@ -510,7 +510,7 @@ abstract class Device {
   /// defaults to all users (Android only).
   Future<bool> uninstallApp(
     covariant ApplicationPackage app, {
-    String userIdentifier,
+    String? userIdentifier,
   });
 
   /// Check if the device is supported by Flutter.
@@ -550,12 +550,12 @@ abstract class Device {
   /// reader will also include log messages from before the invocation time.
   /// Defaults to false.
   FutureOr<DeviceLogReader> getLogReader({
-    covariant ApplicationPackage app,
+    covariant ApplicationPackage? app,
     bool includePastLogs = false,
   });
 
   /// Get the port forwarder for this device.
-  DevicePortForwarder get portForwarder;
+  DevicePortForwarder? get portForwarder;
 
   /// Get the DDS instance for this device.
   final DartDevelopmentService dds = DartDevelopmentService();
@@ -572,13 +572,13 @@ abstract class Device {
   /// start call. The build mode is not used by all platforms.
   Future<LaunchResult> startApp(
     covariant ApplicationPackage package, {
-    String mainPath,
-    String route,
-    DebuggingOptions debuggingOptions,
+    String? mainPath,
+    String? route,
+    required DebuggingOptions debuggingOptions,
     Map<String, Object?> platformArgs,
     bool prebuiltApplication = false,
     bool ipv6 = false,
-    String userIdentifier,
+    String? userIdentifier,
   });
 
   /// Whether this device implements support for hot reload.
@@ -603,7 +603,7 @@ abstract class Device {
   /// Specify [userIdentifier] to stop app installed to a profile (Android only).
   Future<bool> stopApp(
     covariant ApplicationPackage app, {
-    String userIdentifier,
+    String? userIdentifier,
   });
 
   /// Query the current application memory usage..
@@ -917,7 +917,7 @@ class DiscoveredApp {
 
 // An empty device log reader
 class NoOpDeviceLogReader implements DeviceLogReader {
-  NoOpDeviceLogReader(this.name);
+  NoOpDeviceLogReader(String? nameOrNull) : name = nameOrNull ?? '';
 
   @override
   final String name;

packages/flutter_tools/lib/src/web/web_device.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 'package:meta/meta.dart';
 import 'package:process/process.dart';
 
@@ -36,10 +34,10 @@ class WebApplicationPackage extends ApplicationPackage {
 /// A web device that supports a chromium browser.
 abstract class ChromiumDevice extends Device {
   ChromiumDevice({
-    @required String name,
-    @required this.chromeLauncher,
-    @required FileSystem fileSystem,
-    @required Logger logger,
+    required String name,
+    required this.chromeLauncher,
+    required FileSystem fileSystem,
+    required Logger logger,
   }) : _fileSystem = fileSystem,
        _logger = logger,
        super(
@@ -55,7 +53,7 @@ abstract class ChromiumDevice extends Device {
   final Logger _logger;
 
   /// The active chrome instance.
-  Chromium _chrome;
+  Chromium? _chrome;
 
   // This device does not actually support hot reload, but the current implementation of the resident runner
   // requires both supportsHotReload and supportsHotRestart to be true in order to allow hot restart.
@@ -80,11 +78,11 @@ abstract class ChromiumDevice extends Device {
   @override
   void clearLogs() { }
 
-  DeviceLogReader _logReader;
+  DeviceLogReader? _logReader;
 
   @override
   DeviceLogReader getLogReader({
-    ApplicationPackage app,
+    ApplicationPackage? app,
     bool includePastLogs = false,
   }) {
     return _logReader ??= NoOpDeviceLogReader(app?.name);
@@ -93,13 +91,13 @@ abstract class ChromiumDevice extends Device {
   @override
   Future<bool> installApp(
     ApplicationPackage app, {
-    String userIdentifier,
+    String? userIdentifier,
   }) async => true;
 
   @override
   Future<bool> isAppInstalled(
     ApplicationPackage app, {
-    String userIdentifier,
+    String? userIdentifier,
   }) async => true;
 
   @override
@@ -109,28 +107,28 @@ abstract class ChromiumDevice extends Device {
   Future<bool> get isLocalEmulator async => false;
 
   @override
-  Future<String> get emulatorId async => null;
+  Future<String?> get emulatorId async => null;
 
   @override
   bool isSupported() =>  chromeLauncher.canFindExecutable();
 
   @override
-  DevicePortForwarder get portForwarder => const NoOpDevicePortForwarder();
+  DevicePortForwarder? get portForwarder => const NoOpDevicePortForwarder();
 
   @override
   Future<LaunchResult> startApp(
     covariant WebApplicationPackage package, {
-    String mainPath,
-    String route,
-    DebuggingOptions debuggingOptions,
-    Map<String, Object> platformArgs,
+    String? mainPath,
+    String? route,
+    required DebuggingOptions debuggingOptions,
+    Map<String, Object?> platformArgs = const <String, Object?>{},
     bool prebuiltApplication = false,
     bool ipv6 = false,
-    String userIdentifier,
+    String? userIdentifier,
   }) async {
     // See [ResidentWebRunner.run] in flutter_tools/lib/src/resident_web_runner.dart
     // for the web initialization and server logic.
-    final String url = platformArgs['uri'] as String;
+    final String url = platformArgs['uri']! as String;
     final bool launchChrome = platformArgs['no-launch-chrome'] != true;
     if (launchChrome) {
       _chrome = await chromeLauncher.launch(
@@ -142,14 +140,14 @@ abstract class ChromiumDevice extends Device {
         debugPort: debuggingOptions.webBrowserDebugPort,
       );
     }
-    _logger.sendEvent('app.webLaunchUrl', <String, dynamic>{'url': url, 'launched': launchChrome});
+    _logger.sendEvent('app.webLaunchUrl', <String, Object>{'url': url, 'launched': launchChrome});
     return LaunchResult.succeeded(observatoryUri: url != null ? Uri.parse(url): null);
   }
 
   @override
   Future<bool> stopApp(
     ApplicationPackage app, {
-    String userIdentifier,
+    String? userIdentifier,
   }) async {
     await _chrome?.close();
     return true;
@@ -161,7 +159,7 @@ abstract class ChromiumDevice extends Device {
   @override
   Future<bool> uninstallApp(
     ApplicationPackage app, {
-    String userIdentifier,
+    String? userIdentifier,
   }) async => true;
 
   @override
@@ -179,11 +177,11 @@ abstract class ChromiumDevice extends Device {
 /// The Google Chrome browser based on Chromium.
 class GoogleChromeDevice extends ChromiumDevice {
   GoogleChromeDevice({
-    @required Platform platform,
-    @required ProcessManager processManager,
-    @required ChromiumLauncher chromiumLauncher,
-    @required Logger logger,
-    @required FileSystem fileSystem,
+    required Platform platform,
+    required ProcessManager processManager,
+    required ChromiumLauncher chromiumLauncher,
+    required Logger logger,
+    required FileSystem fileSystem,
   }) : _platform = platform,
        _processManager = processManager,
        super(
@@ -200,9 +198,8 @@ class GoogleChromeDevice extends ChromiumDevice {
   String get name => 'Chrome';
 
   @override
-  Future<String> get sdkNameAndVersion async => _sdkNameAndVersion ??= await _computeSdkNameAndVersion();
+  late final Future<String> sdkNameAndVersion = _computeSdkNameAndVersion();
 
-  String _sdkNameAndVersion;
   Future<String> _computeSdkNameAndVersion() async {
     if (!isSupported()) {
       return 'unknown';
@@ -238,10 +235,10 @@ class GoogleChromeDevice extends ChromiumDevice {
 /// The Microsoft Edge browser based on Chromium.
 class MicrosoftEdgeDevice extends ChromiumDevice {
   MicrosoftEdgeDevice({
-    @required ChromiumLauncher chromiumLauncher,
-    @required Logger logger,
-    @required FileSystem fileSystem,
-    @required ProcessManager processManager,
+    required ChromiumLauncher chromiumLauncher,
+    required Logger logger,
+    required FileSystem fileSystem,
+    required ProcessManager processManager,
   }) : _processManager = processManager,
        super(
          name: 'edge',
@@ -260,7 +257,7 @@ class MicrosoftEdgeDevice extends ChromiumDevice {
 
   Future<bool> _meetsVersionConstraint() async {
     final String rawVersion = (await sdkNameAndVersion).replaceFirst('Microsoft Edge ', '');
-    final Version version = Version.parse(rawVersion);
+    final Version? version = Version.parse(rawVersion);
     if (version == null) {
       return false;
     }
@@ -268,8 +265,8 @@ class MicrosoftEdgeDevice extends ChromiumDevice {
   }
 
   @override
-  Future<String> get sdkNameAndVersion async => _sdkNameAndVersion ??= await _getSdkNameAndVersion();
-  String _sdkNameAndVersion;
+  late final Future<String> sdkNameAndVersion = _getSdkNameAndVersion();
+
   Future<String> _getSdkNameAndVersion() async {
     if (_processManager.canRun('reg')) {
       final ProcessResult result = await _processManager.run(<String>[
@@ -290,12 +287,15 @@ class MicrosoftEdgeDevice extends ChromiumDevice {
 
 class WebDevices extends PollingDeviceDiscovery {
   WebDevices({
-    @required FileSystem fileSystem,
-    @required Logger logger,
-    @required Platform platform,
-    @required ProcessManager processManager,
-    @required FeatureFlags featureFlags,
+    required FileSystem fileSystem,
+    required Logger logger,
+    required Platform platform,
+    required ProcessManager processManager,
+    required FeatureFlags featureFlags,
   }) : _featureFlags = featureFlags,
+       _webServerDevice = WebServerDevice(
+         logger: logger,
+       ),
        super('Chrome') {
     final OperatingSystemUtils operatingSystemUtils = OperatingSystemUtils(
       fileSystem: fileSystem,
@@ -332,31 +332,29 @@ class WebDevices extends PollingDeviceDiscovery {
         fileSystem: fileSystem,
       );
     }
-    _webServerDevice = WebServerDevice(
-      logger: logger,
-    );
   }
 
-  GoogleChromeDevice _chromeDevice;
-  WebServerDevice _webServerDevice;
-  MicrosoftEdgeDevice _edgeDevice;
+  late final GoogleChromeDevice _chromeDevice;
+  final WebServerDevice _webServerDevice;
+  MicrosoftEdgeDevice? _edgeDevice;
   final FeatureFlags _featureFlags;
 
   @override
   bool get canListAnything => featureFlags.isWebEnabled;
 
   @override
-  Future<List<Device>> pollingGetDevices({ Duration timeout }) async {
+  Future<List<Device>> pollingGetDevices({ Duration? timeout }) async {
     if (!_featureFlags.isWebEnabled) {
       return <Device>[];
     }
+    final MicrosoftEdgeDevice? edgeDevice = _edgeDevice;
     return <Device>[
       if (WebServerDevice.showWebServerDevice)
         _webServerDevice,
       if (_chromeDevice.isSupported())
         _chromeDevice,
-      if (await _edgeDevice?._meetsVersionConstraint() ?? false)
-        _edgeDevice,
+      if (edgeDevice != null && await edgeDevice._meetsVersionConstraint())
+        edgeDevice,
     ];
   }
 
@@ -376,7 +374,7 @@ String parseVersionForWindows(String input) {
 /// A special device type to allow serving for arbitrary browsers.
 class WebServerDevice extends Device {
   WebServerDevice({
-    @required Logger logger,
+    required Logger logger,
   }) : _logger = logger,
        super(
          'web-server',
@@ -394,13 +392,13 @@ class WebServerDevice extends Device {
   void clearLogs() { }
 
   @override
-  Future<String> get emulatorId async => null;
+  Future<String?> get emulatorId async => null;
 
-  DeviceLogReader _logReader;
+  DeviceLogReader? _logReader;
 
   @override
   DeviceLogReader getLogReader({
-    ApplicationPackage app,
+    ApplicationPackage? app,
     bool includePastLogs = false,
   }) {
     return _logReader ??= NoOpDeviceLogReader(app?.name);
@@ -409,13 +407,13 @@ class WebServerDevice extends Device {
   @override
   Future<bool> installApp(
     ApplicationPackage app, {
-    String userIdentifier,
+    String? userIdentifier,
   }) async => true;
 
   @override
   Future<bool> isAppInstalled(
     ApplicationPackage app, {
-    String userIdentifier,
+    String? userIdentifier,
   }) async => true;
 
   @override
@@ -442,22 +440,22 @@ class WebServerDevice extends Device {
   String get name => 'Web Server';
 
   @override
-  DevicePortForwarder get portForwarder => const NoOpDevicePortForwarder();
+  DevicePortForwarder? get portForwarder => const NoOpDevicePortForwarder();
 
   @override
   Future<String> get sdkNameAndVersion async => 'Flutter Tools';
 
   @override
   Future<LaunchResult> startApp(ApplicationPackage package, {
-    String mainPath,
-    String route,
-    DebuggingOptions debuggingOptions,
-    Map<String, Object> platformArgs,
+    String? mainPath,
+    String? route,
+    required DebuggingOptions debuggingOptions,
+    Map<String, Object?> platformArgs = const <String, Object?>{},
     bool prebuiltApplication = false,
     bool ipv6 = false,
-    String userIdentifier,
+    String? userIdentifier,
   }) async {
-    final String url = platformArgs['uri'] as String;
+    final String? url = platformArgs['uri'] as String?;
     if (debuggingOptions.startPaused) {
       _logger.printStatus('Waiting for connection from Dart debug extension at $url', emphasis: true);
     } else {
@@ -467,14 +465,14 @@ class WebServerDevice extends Device {
       'The web-server device requires the Dart Debug Chrome extension for debugging. '
       'Consider using the Chrome or Edge devices for an improved development workflow.'
     );
-    _logger.sendEvent('app.webLaunchUrl', <String, dynamic>{'url': url, 'launched': false});
+    _logger.sendEvent('app.webLaunchUrl', <String, Object?>{'url': url, 'launched': false});
     return LaunchResult.succeeded(observatoryUri: url != null ? Uri.parse(url): null);
   }
 
   @override
   Future<bool> stopApp(
     ApplicationPackage app, {
-    String userIdentifier,
+    String? userIdentifier,
   }) async {
     return true;
   }
@@ -485,7 +483,7 @@ class WebServerDevice extends Device {
   @override
   Future<bool> uninstallApp(
     ApplicationPackage app, {
-    String userIdentifier,
+    String? userIdentifier,
   }) async {
     return true;
   }

packages/flutter_tools/test/general.shard/web/devices_test.dart

@@ -2,9 +2,10 @@
 // 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';
+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/build_info.dart';
@@ -32,8 +33,10 @@ void main() {
   });
 
   testWithoutContext('GoogleChromeDevice defaults', () async {
+    final TestChromiumLauncher launcher = TestChromiumLauncher();
+
     final GoogleChromeDevice chromeDevice = GoogleChromeDevice(
-      chromiumLauncher: null,
+      chromiumLauncher: launcher,
       fileSystem: MemoryFileSystem.test(),
       logger: BufferLogger.test(),
       platform: FakePlatform(),
@@ -50,7 +53,7 @@ void main() {
     expect(await chromeDevice.isLocalEmulator, false);
     expect(chromeDevice.getLogReader(), isA<NoOpDeviceLogReader>());
     expect(chromeDevice.getLogReader(), isA<NoOpDeviceLogReader>());
-    expect(await chromeDevice.portForwarder.forward(1), 1);
+    expect(await chromeDevice.portForwarder!.forward(1), 1);
 
     expect(chromeDevice.supportsRuntimeMode(BuildMode.debug), true);
     expect(chromeDevice.supportsRuntimeMode(BuildMode.profile), true);
@@ -59,8 +62,10 @@ void main() {
   });
 
   testWithoutContext('MicrosoftEdge defaults', () async {
+    final TestChromiumLauncher launcher = TestChromiumLauncher();
+
     final MicrosoftEdgeDevice chromeDevice = MicrosoftEdgeDevice(
-      chromiumLauncher: null,
+      chromiumLauncher: launcher,
       fileSystem: MemoryFileSystem.test(),
       logger: BufferLogger.test(),
       processManager: FakeProcessManager.any(),
@@ -76,7 +81,7 @@ void main() {
     expect(await chromeDevice.isLocalEmulator, false);
     expect(chromeDevice.getLogReader(), isA<NoOpDeviceLogReader>());
     expect(chromeDevice.getLogReader(), isA<NoOpDeviceLogReader>());
-    expect(await chromeDevice.portForwarder.forward(1), 1);
+    expect(await chromeDevice.portForwarder!.forward(1), 1);
 
     expect(chromeDevice.supportsRuntimeMode(BuildMode.debug), true);
     expect(chromeDevice.supportsRuntimeMode(BuildMode.profile), true);
@@ -99,7 +104,7 @@ void main() {
     expect(await device.isLocalEmulator, false);
     expect(device.getLogReader(), isA<NoOpDeviceLogReader>());
     expect(device.getLogReader(), isA<NoOpDeviceLogReader>());
-    expect(await device.portForwarder.forward(1), 1);
+    expect(await device.portForwarder!.forward(1), 1);
 
     expect(device.supportsRuntimeMode(BuildMode.debug), true);
     expect(device.supportsRuntimeMode(BuildMode.profile), true);
@@ -353,3 +358,38 @@ void main() {
     expect((await macosWebDevices.pollingGetDevices()).whereType<MicrosoftEdgeDevice>(), isEmpty);
   });
 }
+
+/// A test implementation of the [ChromiumLauncher] that launches a fixed instance.
+class TestChromiumLauncher implements ChromiumLauncher {
+  TestChromiumLauncher();
+
+  bool _hasInstance = false;
+  void setInstance(Chromium chromium) {
+    _hasInstance = true;
+    currentCompleter.complete(chromium);
+  }
+
+  @override
+  Completer<Chromium> currentCompleter = Completer<Chromium>();
+
+  @override
+  bool canFindExecutable() {
+    return true;
+  }
+
+  @override
+  Future<Chromium> get connectedInstance => currentCompleter.future;
+
+  @override
+  String findExecutable() {
+    return 'chrome';
+  }
+
+  @override
+  bool get hasChromeInstance => _hasInstance;
+
+  @override
+  Future<Chromium> launch(String url, {bool headless = false, int? debugPort, bool skipCheck = false, Directory? cacheDir}) async {
+    return currentCompleter.future;
+  }
+}