Migrate a few tool libraries to null safety (#83862)

packages/flutter_tools/lib/src/build_system/targets/dart_plugin_registrant.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:package_config/package_config.dart';
 
@@ -30,7 +28,7 @@ class DartPluginRegistrantTarget extends Target {
 
   DartPluginRegistrantTarget._(this._project);
 
-  final FlutterProject _project;
+  final FlutterProject? _project;
 
   @override
   Future<void> build(Environment environment) async {
@@ -66,11 +64,11 @@ class DartPluginRegistrantTarget extends Target {
     if (!environment.generateDartPluginRegistry) {
       return true;
     }
-    final String platformName = environment.defines[kTargetPlatform];
+    final String? platformName = environment.defines[kTargetPlatform];
     if (platformName == null) {
       return true;
     }
-    final TargetPlatform targetPlatform = getTargetPlatformForName(platformName);
+    final TargetPlatform? targetPlatform = getTargetPlatformForName(platformName);
     // TODO(egarciad): Support Android and iOS.
     // https://github.com/flutter/flutter/issues/52267
     return targetPlatform != TargetPlatform.darwin &&

packages/flutter_tools/lib/src/globals.dart

@@ -9,7 +9,6 @@ import 'device.dart';
 import 'doctor.dart';
 import 'fuchsia/fuchsia_sdk.dart';
 import 'ios/simulators.dart';
-import 'macos/cocoapods_validator.dart';
 import 'macos/xcdevice.dart';
 import 'reporting/crash_reporting.dart';
 import 'runner/local_engine.dart';
@@ -20,8 +19,6 @@ CrashReporter get crashReporter => context.get<CrashReporter>();
 Doctor get doctor => context.get<Doctor>();
 DeviceManager get deviceManager => context.get<DeviceManager>();
 
-CocoaPodsValidator get cocoapodsValidator => context.get<CocoaPodsValidator>();
-
 LocalEngineLocator get localEngineLocator => context.get<LocalEngineLocator>();
 FuchsiaArtifacts get fuchsiaArtifacts => context.get<FuchsiaArtifacts>();
 IOSSimulatorUtils get iosSimulatorUtils => context.get<IOSSimulatorUtils>();

packages/flutter_tools/lib/src/globals_null_migrated.dart

@@ -30,6 +30,7 @@ import 'ios/ios_workflow.dart';
 import 'ios/plist_parser.dart';
 import 'ios/xcodeproj.dart';
 import 'macos/cocoapods.dart';
+import 'macos/cocoapods_validator.dart';
 import 'macos/xcode.dart';
 import 'persistent_tool_state.dart';
 import 'project.dart';
@@ -39,6 +40,7 @@ import 'version.dart';
 Artifacts? get artifacts => context.get<Artifacts>();
 BuildSystem? get buildSystem => context.get<BuildSystem>();
 Cache get cache => context.get<Cache>()!;
+CocoaPodsValidator? get cocoapodsValidator => context.get<CocoaPodsValidator>();
 Config get config => context.get<Config>()!;
 HttpClientFactory? get httpClientFactory => context.get<HttpClientFactory>();
 Logger get logger => context.get<Logger>()!;

packages/flutter_tools/lib/src/linux/application_package.dart

@@ -2,10 +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 '../application_package.dart';
 import '../base/file_system.dart';
 import '../build_info.dart';
@@ -14,7 +10,7 @@ import '../globals_null_migrated.dart' as globals;
 import '../project.dart';
 
 abstract class LinuxApp extends ApplicationPackage {
-  LinuxApp({@required String projectBundleId}) : super(id: projectBundleId);
+  LinuxApp({required String projectBundleId}) : super(id: projectBundleId);
 
   /// Creates a new [LinuxApp] from a linux sub project.
   factory LinuxApp.fromLinuxProject(LinuxProject project) {
@@ -40,7 +36,7 @@ abstract class LinuxApp extends ApplicationPackage {
 
 class PrebuiltLinuxApp extends LinuxApp {
   PrebuiltLinuxApp({
-    @required String executable,
+    required String executable,
   }) : _executable = executable,
        super(projectBundleId: executable);
 
@@ -54,13 +50,13 @@ class PrebuiltLinuxApp extends LinuxApp {
 }
 
 class BuildableLinuxApp extends LinuxApp {
-  BuildableLinuxApp({this.project}) : super(projectBundleId: project.parent.manifest.appName);
+  BuildableLinuxApp({required this.project}) : super(projectBundleId: project.parent.manifest.appName);
 
   final LinuxProject project;
 
   @override
   String executable(BuildMode buildMode) {
-    final String binaryName = getCmakeExecutableName(project);
+    final String? binaryName = getCmakeExecutableName(project);
     return globals.fs.path.join(
         getLinuxBuildDirectory(),
         getNameForBuildMode(buildMode),

packages/flutter_tools/lib/src/linux/build_linux.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 '../artifacts.dart';
 import '../base/analyze_size.dart';
 import '../base/common.dart';
@@ -32,7 +30,7 @@ Future<void> buildLinux(
   LinuxProject linuxProject,
   BuildInfo buildInfo, {
     String target = 'lib/main.dart',
-    SizeAnalyzer sizeAnalyzer,
+    SizeAnalyzer? sizeAnalyzer,
     bool needCrossBuild = false,
     TargetPlatform targetPlatform = TargetPlatform.linux_x64,
     String targetSysroot = '/',
@@ -56,13 +54,14 @@ Future<void> buildLinux(
   // step.
   final Map<String, String> environmentConfig = buildInfo.toEnvironmentConfig();
   environmentConfig['FLUTTER_TARGET'] = target;
-  if (globals.artifacts is LocalEngineArtifacts) {
-    final LocalEngineArtifacts localEngineArtifacts = globals.artifacts as LocalEngineArtifacts;
+  final Artifacts? artifacts = globals.artifacts;
+  if (artifacts is LocalEngineArtifacts) {
+    final LocalEngineArtifacts localEngineArtifacts = artifacts;
     final String engineOutPath = localEngineArtifacts.engineOutPath;
     environmentConfig['FLUTTER_ENGINE'] = globals.fs.path.dirname(globals.fs.path.dirname(engineOutPath));
     environmentConfig['LOCAL_ENGINE'] = globals.fs.path.basename(engineOutPath);
   }
-  writeGeneratedCmakeConfig(Cache.flutterRoot, linuxProject, environmentConfig);
+  writeGeneratedCmakeConfig(Cache.flutterRoot!, linuxProject, environmentConfig);
 
   createPluginSymlinks(linuxProject.parent);
 
@@ -70,7 +69,7 @@ Future<void> buildLinux(
     'Building Linux application...',
   );
   try {
-    final String buildModeName = getNameForBuildMode(buildInfo.mode ?? BuildMode.release);
+    final String buildModeName = getNameForBuildMode(buildInfo.mode);
     final Directory buildDirectory =
         globals.fs.directory(getLinuxBuildDirectory(targetPlatform)).childDirectory(buildModeName);
     await _runCmake(buildModeName, linuxProject.cmakeFile.parent, buildDirectory,
@@ -85,7 +84,7 @@ Future<void> buildLinux(
       .childFile('snapshot.$arch.json');
     final File precompilerTrace = globals.fs.directory(buildInfo.codeSizeDirectory)
       .childFile('trace.$arch.json');
-    final Map<String, Object> output = await sizeAnalyzer.analyzeAotSnapshot(
+    final Map<String, Object?> output = await sizeAnalyzer.analyzeAotSnapshot(
       aotSnapshot: codeSizeFile,
       // This analysis is only supported for release builds.
       outputDirectory: globals.fs.directory(

packages/flutter_tools/lib/src/macos/cocoapod_utils.dart

@@ -2,13 +2,11 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @dart = 2.8
-
 import '../base/fingerprint.dart';
 import '../build_info.dart';
 import '../cache.dart';
 import '../flutter_plugins.dart';
-import '../globals.dart' as globals;
+import '../globals_null_migrated.dart' as globals;
 import '../project.dart';
 
 /// For a given build, determines whether dependencies have changed since the
@@ -32,7 +30,7 @@ Future<void> processPodsIfNeeded(
       xcodeProject.podfile.path,
       xcodeProject.generatedXcodePropertiesFile.path,
       globals.fs.path.join(
-        Cache.flutterRoot,
+        Cache.flutterRoot!,
         'packages',
         'flutter_tools',
         'bin',
@@ -43,11 +41,11 @@ Future<void> processPodsIfNeeded(
     logger: globals.logger,
   );
 
-  final bool didPodInstall = await globals.cocoaPods.processPods(
+  final bool didPodInstall = await globals.cocoaPods?.processPods(
     xcodeProject: xcodeProject,
     buildMode: buildMode,
     dependenciesChanged: !fingerprinter.doesFingerprintMatch(),
-  );
+  ) == true;
   if (didPodInstall) {
     fingerprinter.writeFingerprint();
   }

packages/flutter_tools/lib/src/macos/cocoapods_validator.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 '../base/user_messages.dart';
 import '../doctor_validator.dart';
 import 'cocoapods.dart';
@@ -32,7 +30,7 @@ class CocoaPodsValidator extends DoctorValidator {
 
     ValidationType status = ValidationType.installed;
     if (cocoaPodsStatus == CocoaPodsStatus.recommended) {
-      messages.add(ValidationMessage(_userMessages.cocoaPodsVersion(await _cocoaPods.cocoaPodsVersionText)));
+      messages.add(ValidationMessage(_userMessages.cocoaPodsVersion((await _cocoaPods.cocoaPodsVersionText).toString())));
     } else {
       if (cocoaPodsStatus == CocoaPodsStatus.notInstalled) {
         status = ValidationType.missing;
@@ -50,7 +48,7 @@ class CocoaPodsValidator extends DoctorValidator {
           _userMessages.cocoaPodsUnknownVersion(unknownCocoaPodsConsequence, cocoaPodsInstallInstructions)));
       } else {
         status = ValidationType.partial;
-        final String currentVersionText = await _cocoaPods.cocoaPodsVersionText;
+        final String currentVersionText = (await _cocoaPods.cocoaPodsVersionText).toString();
         messages.add(ValidationMessage.hint(
           _userMessages.cocoaPodsOutdated(currentVersionText, cocoaPodsRecommendedVersion.toString(), noCocoaPodsConsequence, cocoaPodsInstallInstructions)));
       }

packages/flutter_tools/lib/src/macos/migrations/remove_macos_framework_link_and_embedding_migration.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 '../../base/common.dart';
 import '../../base/file_system.dart';
 import '../../base/logger.dart';
@@ -38,7 +36,7 @@ class RemoveMacOSFrameworkLinkAndEmbeddingMigration extends ProjectMigrator {
   }
 
   @override
-  String migrateLine(String line) {
+  String? migrateLine(String line) {
     // App.framework Frameworks reference.
     // isa = PBXFrameworksBuildPhase;
     // files = (

packages/flutter_tools/lib/src/migrations/cmake_custom_command_migration.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 '../base/file_system.dart';
 import '../base/logger.dart';
 import '../base/project_migrator.dart';
@@ -51,8 +49,8 @@ class CmakeCustomCommandMigration extends ProjectMigrator {
     final Iterable<RegExpMatch> matches = addCustomCommand.allMatches(originalProjectContents);
 
     for (final RegExpMatch match in matches) {
-      final String addCustomCommandOriginal = match.group(1);
-      if (addCustomCommandOriginal?.contains('VERBATIM') == false) {
+      final String? addCustomCommandOriginal = match.group(1);
+      if (addCustomCommandOriginal != null && addCustomCommandOriginal.contains('VERBATIM') == false) {
         final String addCustomCommandReplacement = '$addCustomCommandOriginal\n  VERBATIM';
         newProjectContents = newProjectContents.replaceAll(addCustomCommandOriginal, addCustomCommandReplacement);
       }

packages/flutter_tools/lib/src/runner/local_engine.dart

@@ -2,9 +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:package_config/package_config.dart';
 
 import '../artifacts.dart';
@@ -31,11 +28,11 @@ import '../dart/package_map.dart';
 /// For more information on local engines, see CONTRIBUTING.md.
 class LocalEngineLocator {
   LocalEngineLocator({
-    @required Platform platform,
-    @required Logger logger,
-    @required FileSystem fileSystem,
-    @required String flutterRoot,
-    @required UserMessages userMessages,
+    required Platform platform,
+    required Logger logger,
+    required FileSystem fileSystem,
+    required String flutterRoot,
+    required UserMessages userMessages,
   }) : _platform = platform,
        _logger = logger,
        _fileSystem = fileSystem,
@@ -49,7 +46,7 @@ class LocalEngineLocator {
   final UserMessages _userMessages;
 
   /// Returns the engine build path of a local engine if one is located, otherwise `null`.
-  Future<EngineBuildPaths> findEnginePath(String engineSourcePath, String localEngine, String packagePath) async {
+  Future<EngineBuildPaths?> findEnginePath(String? engineSourcePath, String? localEngine, String? packagePath) async {
     engineSourcePath ??= _platform.environment[kFlutterEngineEnvironmentVariableName];
 
     if (engineSourcePath == null && localEngine != null) {
@@ -89,15 +86,15 @@ class LocalEngineLocator {
     return null;
   }
 
-  String _findEngineSourceByLocalEngine(String localEngine) {
+  String? _findEngineSourceByLocalEngine(String localEngine) {
     // When the local engine is an absolute path to a variant inside the
     // out directory, parse the engine source.
     // --local-engine /path/to/cache/builder/src/out/host_debug_unopt
     if (_fileSystem.path.isAbsolute(localEngine)) {
       final Directory localEngineDirectory = _fileSystem.directory(localEngine);
-      final Directory outDirectory = localEngineDirectory?.parent;
-      final Directory srcDirectory = outDirectory?.parent;
-      if (localEngineDirectory.existsSync() && outDirectory?.basename == 'out' && srcDirectory?.basename == 'src') {
+      final Directory outDirectory = localEngineDirectory.parent;
+      final Directory srcDirectory = outDirectory.parent;
+      if (localEngineDirectory.existsSync() && outDirectory.basename == 'out' && srcDirectory.basename == 'src') {
         _logger.printTrace('Parsed engine source from local engine as ${srcDirectory.path}.');
         return srcDirectory.path;
       }
@@ -105,7 +102,7 @@ class LocalEngineLocator {
     return null;
   }
 
-  Future<String> _findEngineSourceByPackageConfig(String packagePath) async {
+  Future<String?> _findEngineSourceByPackageConfig(String? packagePath) async {
     final PackageConfig packageConfig = await loadPackageConfigWithLogging(
       _fileSystem.file(
         // TODO(jonahwilliams): update to package_config
@@ -115,7 +112,7 @@ class LocalEngineLocator {
       throwOnError: false,
     );
     // Skip if sky_engine is the version in bin/cache.
-    Uri engineUri = packageConfig[kFlutterEnginePackageName]?.packageUriRoot;
+    Uri? engineUri = packageConfig[kFlutterEnginePackageName]?.packageUriRoot;
     final String cachedPath = _fileSystem.path.join(_flutterRoot, 'bin', 'cache', 'pkg', kFlutterEnginePackageName, 'lib');
     if (engineUri != null && _fileSystem.identicalSync(cachedPath, engineUri.path)) {
       _logger.printTrace('Local engine auto-detection sky_engine in $packagePath is the same version in bin/cache.');
@@ -125,16 +122,17 @@ class LocalEngineLocator {
     // determine the engineSourcePath by sky_engine setting. A typical engine Uri
     // looks like:
     // file://flutter-engine-local-path/src/out/host_debug_unopt/gen/dart-pkg/sky_engine/lib/
-    String engineSourcePath;
-    if (engineUri?.path != null) {
-      engineSourcePath = _fileSystem.directory(engineUri.path)
-        ?.parent
-        ?.parent
-        ?.parent
-        ?.parent
-        ?.parent
-        ?.parent
-        ?.path;
+    String? engineSourcePath;
+    final String? engineUriPath = engineUri?.path;
+    if (engineUriPath != null) {
+      engineSourcePath = _fileSystem.directory(engineUriPath)
+        .parent
+        .parent
+        .parent
+        .parent
+        .parent
+        .parent
+        .path;
       if (engineSourcePath != null && (engineSourcePath == _fileSystem.path.dirname(engineSourcePath) || engineSourcePath.isEmpty)) {
         engineSourcePath = null;
         throwToolExit(
@@ -166,7 +164,7 @@ class LocalEngineLocator {
     return 'host_$tmpBasename';
   }
 
-  EngineBuildPaths _findEngineBuildPath(String localEngine, String enginePath) {
+  EngineBuildPaths _findEngineBuildPath(String? localEngine, String enginePath) {
     if (localEngine == null) {
       throwToolExit(_userMessages.runnerLocalEngineRequired, exitCode: 2);
     }
@@ -188,7 +186,7 @@ class LocalEngineLocator {
     return EngineBuildPaths(targetEngine: engineBuildPath, hostEngine: engineHostBuildPath);
   }
 
-  String _tryEnginePath(String enginePath) {
+  String? _tryEnginePath(String enginePath) {
     if (_fileSystem.isDirectorySync(_fileSystem.path.join(enginePath, 'out'))) {
       return enginePath;
     }

packages/flutter_tools/lib/src/windows/uwptool.dart

@@ -2,11 +2,8 @@
 // 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:meta/meta.dart';
 import 'package:process/process.dart';
 
 import '../artifacts.dart';
@@ -21,9 +18,9 @@ import '../base/process.dart';
 /// apps.
 class UwpTool {
   UwpTool({
-    @required Artifacts artifacts,
-    @required Logger logger,
-    @required ProcessManager processManager,
+    required Artifacts artifacts,
+    required Logger logger,
+    required ProcessManager processManager,
   }) : _artifacts = artifacts,
        _logger = logger,
        _processUtils = ProcessUtils(processManager: processManager, logger: logger);
@@ -58,7 +55,7 @@ class UwpTool {
   ///
   /// If no installed application on the system matches the specified package
   /// name, returns null.
-  Future<String/*?*/> getPackageFamilyName(String packageName) async {
+  Future<String?> getPackageFamilyName(String packageName) async {
     for (final String packageFamily in await listApps()) {
       if (packageFamily.startsWith(packageName)) {
         return packageFamily;
@@ -70,7 +67,7 @@ class UwpTool {
   /// Launches the app with the specified package family name.
   ///
   /// On success, returns the process ID of the launched app, otherwise null.
-  Future<int/*?*/> launchApp(String packageFamily, List<String> args) async {
+  Future<int?> launchApp(String packageFamily, List<String> args) async {
     final List<String> launchCommand = <String>[
       _binaryPath,
       'launch',
@@ -82,7 +79,7 @@ class UwpTool {
       return null;
     }
     // Read the process ID from stdout.
-    final int processId = int.tryParse(result.stdout.trim());
+    final int? processId = int.tryParse(result.stdout.trim());
     _logger.printTrace('Launched application $packageFamily with process ID $processId');
     return processId;
   }

packages/flutter_tools/test/general.shard/macos/cocoapods_validator_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 'package:flutter_tools/src/base/user_messages.dart';
 import 'package:flutter_tools/src/doctor_validator.dart';
 import 'package:flutter_tools/src/macos/cocoapods.dart';
@@ -15,7 +13,7 @@ import '../../src/common.dart';
 void main() {
   group('CocoaPods validation', () {
     testWithoutContext('Emits installed status when CocoaPods is installed', () async {
-      final CocoaPodsValidator workflow = CocoaPodsValidator(FakeCocoaPods(CocoaPodsStatus.recommended), UserMessages());
+      final CocoaPodsValidator workflow = CocoaPodsValidator(FakeCocoaPods(CocoaPodsStatus.recommended, '1000.0.0'), UserMessages());
       final ValidationResult result = await workflow.validate();
       expect(result.type, ValidationType.installed);
     });
@@ -55,6 +53,6 @@ class FakeCocoaPods extends Fake implements CocoaPods {
   final CocoaPodsStatus _evaluateCocoaPodsInstallation;
 
   @override
-  Future<String> get cocoaPodsVersionText async => _cocoaPodsVersionText;
-  final String _cocoaPodsVersionText;
+  Future<String?> get cocoaPodsVersionText async => _cocoaPodsVersionText;
+  final String? _cocoaPodsVersionText;
 }

packages/flutter_tools/test/general.shard/macos/macos_project_migration_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 'package:file/file.dart';
 import 'package:file/memory.dart';
 import 'package:flutter_tools/src/base/logger.dart';
@@ -11,17 +9,16 @@ import 'package:flutter_tools/src/base/project_migrator.dart';
 import 'package:flutter_tools/src/macos/migrations/remove_macos_framework_link_and_embedding_migration.dart';
 import 'package:flutter_tools/src/project.dart';
 import 'package:flutter_tools/src/reporting/reporting.dart';
-import 'package:meta/meta.dart';
 import 'package:test/fake.dart';
 
 import '../../src/common.dart';
 
 void main() {
-  TestUsage testUsage;
-  MemoryFileSystem memoryFileSystem;
-  BufferLogger testLogger;
-  FakeMacOSProject macOSProject;
-  File xcodeProjectInfoFile;
+  late TestUsage testUsage;
+  late MemoryFileSystem memoryFileSystem;
+  late BufferLogger testLogger;
+  late FakeMacOSProject macOSProject;
+  late File xcodeProjectInfoFile;
 
   setUp(() {
     testUsage = TestUsage();
@@ -160,11 +157,11 @@ keep this 2
 
 class FakeMacOSProject extends Fake implements MacOSProject {
   @override
-  File xcodeProjectInfoFile;
+  File xcodeProjectInfoFile = MemoryFileSystem.test().file('xcodeProjectInfoFile');
 }
 
 class FakeMacOSMigrator extends ProjectMigrator {
-  FakeMacOSMigrator({@required this.succeeds}) : super(null);
+  FakeMacOSMigrator({required this.succeeds}) : super(BufferLogger.test());
 
   final bool succeeds;
 

packages/flutter_tools/test/general.shard/migrations/cmake_project_migration_test.dart

@@ -2,17 +2,13 @@
 // 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:file/file.dart';
 import 'package:file/memory.dart';
 import 'package:flutter_tools/src/base/logger.dart';
-import 'package:flutter_tools/src/base/platform.dart';
 import 'package:flutter_tools/src/base/project_migrator.dart';
 import 'package:flutter_tools/src/base/terminal.dart';
 import 'package:flutter_tools/src/migrations/cmake_custom_command_migration.dart';
 import 'package:flutter_tools/src/project.dart';
-import 'package:meta/meta.dart';
 import 'package:test/fake.dart';
 
 import '../../src/common.dart';
@@ -32,20 +28,17 @@ void main () {
     });
 
     group('migrate add_custom_command() to use VERBATIM', () {
-      MemoryFileSystem memoryFileSystem;
-      BufferLogger testLogger;
-      FakeCmakeProject mockCmakeProject;
-      File managedCmakeFile;
+      late MemoryFileSystem memoryFileSystem;
+      late BufferLogger testLogger;
+      late FakeCmakeProject mockCmakeProject;
+      late File managedCmakeFile;
 
       setUp(() {
         memoryFileSystem = MemoryFileSystem.test();
         managedCmakeFile = memoryFileSystem.file('CMakeLists.txtx');
 
         testLogger = BufferLogger(
-          terminal: AnsiTerminal(
-            stdio: null,
-            platform: const LocalPlatform(),
-          ),
+          terminal: Terminal.test(),
           outputPreferences: OutputPreferences.test(),
         );
 
@@ -186,8 +179,8 @@ class FakeCmakeProject extends Fake implements CmakeBasedProject {
 }
 
 class FakeCmakeMigrator extends ProjectMigrator {
-  FakeCmakeMigrator({@required this.succeeds})
-    : super(null);
+  FakeCmakeMigrator({required this.succeeds})
+    : super(BufferLogger.test());
 
   final bool succeeds;
 

packages/flutter_tools/test/general.shard/runner/local_engine_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 'package:file/memory.dart';
 import 'package:flutter_tools/src/artifacts.dart';
 import 'package:flutter_tools/src/base/file_system.dart';
@@ -246,8 +244,8 @@ void main() {
 }
 
 Matcher matchesEngineBuildPaths({
-  String hostEngine,
-  String targetEngine,
+  String? hostEngine,
+  String? targetEngine,
 }) {
   return const TypeMatcher<EngineBuildPaths>()
     .having((EngineBuildPaths paths) => paths.hostEngine, 'hostEngine', hostEngine)