Revert "[flutter_tools] Remove sound null safety flag (#120936)" (#122909)

This reverts commit 7c3088cf22c8a863ca38e3890851fd8dc776768d.

dev/bots/test.dart

@@ -573,7 +573,9 @@ Future<void> _runExampleProjectBuildTests(Directory exampleDirectory, [File? mai
   // Only verify caching with flutter gallery.
   final bool verifyCaching = exampleDirectory.path.contains('flutter_gallery');
   final String examplePath = path.relative(exampleDirectory.path, from: Directory.current.path);
+  final bool hasNullSafety = File(path.join(examplePath, 'null_safety')).existsSync();
   final List<String> additionalArgs = <String>[
+    if (hasNullSafety) '--no-sound-null-safety',
     if (mainFile != null) path.relative(mainFile.path, from: exampleDirectory.absolute.path),
   ];
   if (Directory(path.join(examplePath, 'android')).existsSync()) {
@@ -769,6 +771,8 @@ Future<void> _runAddToAppLifeCycleTests() async {
 }
 
 Future<void> _runFrameworkTests() async {
+  final List<String> soundNullSafetyOptions     = <String>['--null-assertions', '--sound-null-safety'];
+  final List<String> mixedModeNullSafetyOptions = <String>['--null-assertions', '--no-sound-null-safety'];
   final List<String> trackWidgetCreationAlternatives = <String>['--track-widget-creation', '--no-track-widget-creation'];
 
   Future<void> runWidgets() async {
@@ -776,7 +780,7 @@ Future<void> _runFrameworkTests() async {
     for (final String trackWidgetCreationOption in trackWidgetCreationAlternatives) {
       await _runFlutterTest(
         path.join(flutterRoot, 'packages', 'flutter'),
-        options: <String>[trackWidgetCreationOption],
+        options: <String>[trackWidgetCreationOption, ...soundNullSafetyOptions],
         tests: <String>[ path.join('test', 'widgets') + path.separator ],
       );
     }
@@ -791,13 +795,13 @@ Future<void> _runFrameworkTests() async {
     // Run release mode tests (see packages/flutter/test_release/README.md)
     await _runFlutterTest(
       path.join(flutterRoot, 'packages', 'flutter'),
-      options: <String>['--dart-define=dart.vm.product=true'],
+      options: <String>['--dart-define=dart.vm.product=true', ...soundNullSafetyOptions],
       tests: <String>['test_release${path.separator}'],
     );
     // Run profile mode tests (see packages/flutter/test_profile/README.md)
     await _runFlutterTest(
       path.join(flutterRoot, 'packages', 'flutter'),
-      options: <String>['--dart-define=dart.vm.product=false', '--dart-define=dart.vm.profile=true'],
+      options: <String>['--dart-define=dart.vm.product=false', '--dart-define=dart.vm.profile=true', ...soundNullSafetyOptions],
       tests: <String>['test_profile${path.separator}'],
     );
   }
@@ -813,7 +817,7 @@ Future<void> _runFrameworkTests() async {
     for (final String trackWidgetCreationOption in trackWidgetCreationAlternatives) {
       await _runFlutterTest(
         path.join(flutterRoot, 'packages', 'flutter'),
-        options: <String>[trackWidgetCreationOption],
+        options: <String>[trackWidgetCreationOption, ...soundNullSafetyOptions],
         tests: tests,
       );
     }
@@ -833,9 +837,9 @@ Future<void> _runFrameworkTests() async {
         workingDirectory: path.join(flutterRoot, 'examples', 'api'),
       );
     }
-    await _runFlutterTest(path.join(flutterRoot, 'examples', 'api'));
+    await _runFlutterTest(path.join(flutterRoot, 'examples', 'api'), options: soundNullSafetyOptions);
-    await _runFlutterTest(path.join(flutterRoot, 'examples', 'hello_world'));
+    await _runFlutterTest(path.join(flutterRoot, 'examples', 'hello_world'), options: soundNullSafetyOptions);
-    await _runFlutterTest(path.join(flutterRoot, 'examples', 'layers'));
+    await _runFlutterTest(path.join(flutterRoot, 'examples', 'layers'), options: soundNullSafetyOptions);
   }
 
   Future<void> runTracingTests() async {
@@ -941,6 +945,7 @@ Future<void> _runFrameworkTests() async {
 
   Future<void> runPrivateTests() async {
     final List<String> args = <String>[
+      '--sound-null-safety',
       'run',
       'bin/test_private.dart',
     ];
@@ -984,17 +989,17 @@ Future<void> _runFrameworkTests() async {
     await _runFlutterTest(path.join(flutterRoot, 'dev', 'tools', 'gen_defaults'));
     await _runFlutterTest(path.join(flutterRoot, 'dev', 'tools', 'gen_keycodes'));
     await _runFlutterTest(path.join(flutterRoot, 'dev', 'benchmarks', 'test_apps', 'stocks'));
-    await _runFlutterTest(path.join(flutterRoot, 'packages', 'flutter_driver'), tests: <String>[path.join('test', 'src', 'real_tests')]);
+    await _runFlutterTest(path.join(flutterRoot, 'packages', 'flutter_driver'), tests: <String>[path.join('test', 'src', 'real_tests')], options: soundNullSafetyOptions);
     await _runFlutterTest(path.join(flutterRoot, 'packages', 'integration_test'), options: <String>[
       '--enable-vmservice',
       // Web-specific tests depend on Chromium, so they run as part of the web_long_running_tests shard.
       '--exclude-tags=web',
     ]);
-    await _runFlutterTest(path.join(flutterRoot, 'packages', 'flutter_goldens'));
+    await _runFlutterTest(path.join(flutterRoot, 'packages', 'flutter_goldens'), options: soundNullSafetyOptions);
-    await _runFlutterTest(path.join(flutterRoot, 'packages', 'flutter_localizations'));
+    await _runFlutterTest(path.join(flutterRoot, 'packages', 'flutter_localizations'), options: soundNullSafetyOptions);
-    await _runFlutterTest(path.join(flutterRoot, 'packages', 'flutter_test'));
+    await _runFlutterTest(path.join(flutterRoot, 'packages', 'flutter_test'), options: soundNullSafetyOptions);
-    await _runFlutterTest(path.join(flutterRoot, 'packages', 'fuchsia_remote_debug_protocol'));
+    await _runFlutterTest(path.join(flutterRoot, 'packages', 'fuchsia_remote_debug_protocol'), options: soundNullSafetyOptions);
-    await _runFlutterTest(path.join(flutterRoot, 'dev', 'integration_tests', 'non_nullable'));
+    await _runFlutterTest(path.join(flutterRoot, 'dev', 'integration_tests', 'non_nullable'), options: mixedModeNullSafetyOptions);
     const String httpClientWarning =
       'Warning: At least one test in this suite creates an HttpClient. When\n'
       'running a test suite that uses TestWidgetsFlutterBinding, all HTTP\n'
@@ -1224,7 +1229,7 @@ Future<void> _runWebLongRunningTests() async {
     () => _runWebDebugTest('lib/framework_stack_trace.dart'),
     () => _runWebDebugTest('lib/web_directory_loading.dart'),
     () => _runWebDebugTest('test/test.dart'),
-    () => _runWebDebugTest('lib/null_safe_main.dart'),
+    () => _runWebDebugTest('lib/null_safe_main.dart', enableNullSafety: true),
     () => _runWebDebugTest('lib/web_define_loading.dart',
       additionalArguments: <String>[
         '--dart-define=test.valueA=Example,A',
@@ -1237,8 +1242,12 @@ Future<void> _runWebLongRunningTests() async {
         '--dart-define=test.valueB=Value',
       ]
     ),
-    () => _runWebDebugTest('lib/sound_mode.dart'),
+    () => _runWebDebugTest('lib/sound_mode.dart', additionalArguments: <String>[
-    () => _runWebReleaseTest('lib/sound_mode.dart'),
+      '--sound-null-safety',
+    ]),
+    () => _runWebReleaseTest('lib/sound_mode.dart', additionalArguments: <String>[
+      '--sound-null-safety',
+    ]),
     () => _runFlutterWebTest(
       'html',
       path.join(flutterRoot, 'packages', 'integration_test'),
@@ -1297,6 +1306,7 @@ Future<void> _runFlutterDriverWebTest({
       if (driver != null) '--driver=$driver',
       '--target=$target',
       '--browser-name=chrome',
+      '--no-sound-null-safety',
       '-d',
       'web-server',
       '--$buildMode',
@@ -1338,6 +1348,7 @@ Future<void> _runWebTreeshakeTest() async {
       'build',
       'web',
       '--target=$target',
+      '--no-sound-null-safety',
       '--profile',
     ],
     workingDirectory: testAppDirectory,
@@ -1563,6 +1574,7 @@ Future<void> _runGalleryE2eWebTest(String buildMode, { bool canvasKit = false })
       '--driver=test_driver/transitions_perf_e2e_test.dart',
       '--target=test_driver/transitions_perf_e2e.dart',
       '--browser-name=chrome',
+      '--no-sound-null-safety',
       '-d',
       'web-server',
       '--$buildMode',
@@ -1669,6 +1681,7 @@ Future<void> _runWebReleaseTest(String target, {
 ///
 /// Instead, we use `flutter run --debug` and sniff out the standard output.
 Future<void> _runWebDebugTest(String target, {
+  bool enableNullSafety = false,
   List<String> additionalArguments = const<String>[],
 }) async {
   final String testAppDirectory = path.join(flutterRoot, 'dev', 'integration_tests', 'web');
@@ -1682,6 +1695,11 @@ Future<void> _runWebDebugTest(String target, {
     <String>[
       'run',
       '--debug',
+      if (enableNullSafety)
+        ...<String>[
+          '--no-sound-null-safety',
+          '--null-assertions',
+        ],
       '-d',
       'chrome',
       '--web-run-headless',
@@ -1724,6 +1742,7 @@ Future<void> _runFlutterWebTest(String webRenderer, String workingDirectory, Lis
       '--platform=chrome',
       '--web-renderer=$webRenderer',
       '--dart-define=DART_HHH_BOT=$_runningInDartHHHBot',
+      '--sound-null-safety',
       ...flutterTestArgs,
       ...tests,
     ],

packages/flutter/test/foundation/isolates_test.dart

@@ -80,7 +80,8 @@ Future<int> test5CallCompute(int value) {
   return compute(test5, value);
 }
 
-Future<void> expectFileSuccessfullyCompletes(String filename) async {
+Future<void> expectFileSuccessfullyCompletes(String filename,
+    [bool unsound = false]) async {
   // Run a Dart script that calls compute().
   // The Dart process will terminate only if the script exits cleanly with
   // all isolate ports closed.
@@ -92,10 +93,12 @@ Future<void> expectFileSuccessfullyCompletes(String filename) async {
   final String packageRoot = fs.path.dirname(fs.path.fromUri(platform.script));
   final String scriptPath =
       fs.path.join(packageRoot, 'test', 'foundation', filename);
+  final String nullSafetyArg =
+      unsound ? '--no-sound-null-safety' : '--sound-null-safety';
 
   // Enable asserts to also catch potentially invalid assertions.
   final ProcessResult result = await Process.run(
-      dartPath, <String>['run', '--enable-asserts', scriptPath]);
+      dartPath, <String>[nullSafetyArg, 'run', '--enable-asserts', scriptPath]);
   expect(result.exitCode, 0);
 }
 

packages/flutter/test_private/bin/test_private.dart

@@ -225,7 +225,7 @@ class TestCase {
     for (final File test in tests) {
       final String testPath = path.join(path.dirname(test.path), 'lib', path.basenameWithoutExtension(test.path));
       final ProcessRunnerResult result = await runner.runProcess(
-        <String>[flutter, 'test', testPath],
+        <String>[flutter, 'test', '--enable-experiment=non-nullable', '--no-sound-null-safety', '--null-assertions', testPath],
         failOk: true,
       );
       if (result.exitCode != 0) {

packages/flutter_tools/lib/executable.dart

@@ -171,6 +171,7 @@ List<FlutterCommand> generateCommands({
     osUtils: globals.os,
     verboseHelp: verboseHelp,
     androidSdk: globals.androidSdk,
+    logger: globals.logger,
   ),
   ChannelCommand(verboseHelp: verboseHelp),
   CleanCommand(verbose: verbose),

packages/flutter_tools/lib/src/artifacts.dart

@@ -91,7 +91,12 @@ enum HostArtifact {
   webPlatformDart2JSSoundKernelDill,
 
   /// The precompiled SDKs and sourcemaps for web debug builds.
-
+  webPrecompiledSdk,
+  webPrecompiledSdkSourcemaps,
+  webPrecompiledCanvaskitSdk,
+  webPrecompiledCanvaskitSdkSourcemaps,
+  webPrecompiledCanvaskitAndHtmlSdk,
+  webPrecompiledCanvaskitAndHtmlSdkSourcemaps,
   webPrecompiledSoundSdk,
   webPrecompiledSoundSdkSourcemaps,
   webPrecompiledCanvaskitSoundSdk,
@@ -243,10 +248,16 @@ String _hostArtifactToFileName(HostArtifact artifact, Platform platform) {
       return 'dart2js_platform.dill';
     case HostArtifact.flutterWebLibrariesJson:
       return 'libraries.json';
+    case HostArtifact.webPrecompiledSdk:
+    case HostArtifact.webPrecompiledCanvaskitSdk:
+    case HostArtifact.webPrecompiledCanvaskitAndHtmlSdk:
     case HostArtifact.webPrecompiledSoundSdk:
     case HostArtifact.webPrecompiledCanvaskitSoundSdk:
     case HostArtifact.webPrecompiledCanvaskitAndHtmlSoundSdk:
       return 'dart_sdk.js';
+    case HostArtifact.webPrecompiledSdkSourcemaps:
+    case HostArtifact.webPrecompiledCanvaskitSdkSourcemaps:
+    case HostArtifact.webPrecompiledCanvaskitAndHtmlSdkSourcemaps:
     case HostArtifact.webPrecompiledSoundSdkSourcemaps:
     case HostArtifact.webPrecompiledCanvaskitSoundSdkSourcemaps:
     case HostArtifact.webPrecompiledCanvaskitAndHtmlSoundSdkSourcemaps:
@@ -396,6 +407,18 @@ class CachedArtifacts implements Artifacts {
       case HostArtifact.webPlatformDart2JSSoundKernelDill:
         final String path = _fileSystem.path.join(_getFlutterWebSdkPath(), 'kernel', _hostArtifactToFileName(artifact, _platform));
         return _fileSystem.file(path);
+      case HostArtifact.webPrecompiledSdk:
+      case HostArtifact.webPrecompiledSdkSourcemaps:
+        final String path = _fileSystem.path.join(_getFlutterWebSdkPath(), 'kernel', 'amd', _hostArtifactToFileName(artifact, _platform));
+        return _fileSystem.file(path);
+      case HostArtifact.webPrecompiledCanvaskitSdk:
+      case HostArtifact.webPrecompiledCanvaskitSdkSourcemaps:
+        final String path = _fileSystem.path.join(_getFlutterWebSdkPath(), 'kernel', 'amd-canvaskit', _hostArtifactToFileName(artifact, _platform));
+        return _fileSystem.file(path);
+      case HostArtifact.webPrecompiledCanvaskitAndHtmlSdk:
+      case HostArtifact.webPrecompiledCanvaskitAndHtmlSdkSourcemaps:
+        final String path = _fileSystem.path.join(_getFlutterWebSdkPath(), 'kernel', 'amd-canvaskit-html', _hostArtifactToFileName(artifact, _platform));
+        return _fileSystem.file(path);
       case HostArtifact.webPrecompiledSoundSdk:
       case HostArtifact.webPrecompiledSoundSdkSourcemaps:
         final String path = _fileSystem.path.join(_getFlutterWebSdkPath(), 'kernel', 'amd-sound', _hostArtifactToFileName(artifact, _platform));
@@ -828,6 +851,18 @@ class CachedLocalEngineArtifacts implements Artifacts {
       case HostArtifact.webPlatformDart2JSSoundKernelDill:
         final String path = _fileSystem.path.join(_getFlutterWebSdkPath(), 'kernel', _hostArtifactToFileName(artifact, _platform));
         return _fileSystem.file(path);
+      case HostArtifact.webPrecompiledSdk:
+      case HostArtifact.webPrecompiledSdkSourcemaps:
+        final String path = _fileSystem.path.join(_getFlutterWebSdkPath(), 'kernel', 'amd', _hostArtifactToFileName(artifact, _platform));
+        return _fileSystem.file(path);
+      case HostArtifact.webPrecompiledCanvaskitSdk:
+      case HostArtifact.webPrecompiledCanvaskitSdkSourcemaps:
+        final String path = _fileSystem.path.join(_getFlutterWebSdkPath(), 'kernel', 'amd-canvaskit', _hostArtifactToFileName(artifact, _platform));
+        return _fileSystem.file(path);
+      case HostArtifact.webPrecompiledCanvaskitAndHtmlSdk:
+      case HostArtifact.webPrecompiledCanvaskitAndHtmlSdkSourcemaps:
+        final String path = _fileSystem.path.join(_getFlutterWebSdkPath(), 'kernel', 'amd-canvaskit-html', _hostArtifactToFileName(artifact, _platform));
+        return _fileSystem.file(path);
       case HostArtifact.webPrecompiledSoundSdk:
       case HostArtifact.webPrecompiledSoundSdkSourcemaps:
         final String path = _fileSystem.path.join(_getFlutterWebSdkPath(), 'kernel', 'amd-sound', _hostArtifactToFileName(artifact, _platform));
@@ -1118,6 +1153,18 @@ class CachedLocalWebSdkArtifacts implements Artifacts {
       case HostArtifact.webPlatformDart2JSSoundKernelDill:
         final String path = _fileSystem.path.join(_getFlutterWebSdkPath(), 'kernel', _hostArtifactToFileName(artifact, _platform));
         return _fileSystem.file(path);
+      case HostArtifact.webPrecompiledSdk:
+      case HostArtifact.webPrecompiledSdkSourcemaps:
+        final String path = _fileSystem.path.join(_getFlutterWebSdkPath(), 'kernel', 'amd', _hostArtifactToFileName(artifact, _platform));
+        return _fileSystem.file(path);
+      case HostArtifact.webPrecompiledCanvaskitSdk:
+      case HostArtifact.webPrecompiledCanvaskitSdkSourcemaps:
+        final String path = _fileSystem.path.join(_getFlutterWebSdkPath(), 'kernel', 'amd-canvaskit', _hostArtifactToFileName(artifact, _platform));
+        return _fileSystem.file(path);
+      case HostArtifact.webPrecompiledCanvaskitAndHtmlSdk:
+      case HostArtifact.webPrecompiledCanvaskitAndHtmlSdkSourcemaps:
+        final String path = _fileSystem.path.join(_getFlutterWebSdkPath(), 'kernel', 'amd-canvaskit-html', _hostArtifactToFileName(artifact, _platform));
+        return _fileSystem.file(path);
       case HostArtifact.webPrecompiledSoundSdk:
       case HostArtifact.webPrecompiledSoundSdkSourcemaps:
         final String path = _fileSystem.path.join(_getFlutterWebSdkPath(), 'kernel', 'amd-sound', _hostArtifactToFileName(artifact, _platform));

packages/flutter_tools/lib/src/build_info.dart

@@ -40,6 +40,7 @@ class BuildInfo {
     this.performanceMeasurementFile,
     this.dartDefineConfigJsonMap,
     this.packagesPath = '.dart_tool/package_config.json', // TODO(zanderso): make this required and remove the default.
+    this.nullSafetyMode = NullSafetyMode.sound,
     this.codeSizeDirectory,
     this.androidGradleDaemon = true,
     this.packageConfig = PackageConfig.empty,
@@ -53,6 +54,11 @@ class BuildInfo {
 
   final BuildMode mode;
 
+  /// The null safety mode the application should be run in.
+  ///
+  /// If not provided, defaults to [NullSafetyMode.autodetect].
+  final NullSafetyMode nullSafetyMode;
+
   /// Whether the build should subset icon fonts.
   final bool treeShakeIcons;
 

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

@@ -90,6 +90,7 @@ class AttachCommand extends FlutterCommand {
     usesDartDefineOption();
     usesDeviceUserOption();
     addEnableExperimentation(hide: !verboseHelp);
+    addNullSafetyModeOptions(hide: !verboseHelp);
     usesInitializeFromDillOption(hide: !verboseHelp);
     argParser
       ..addOption(

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

@@ -2,9 +2,13 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+import 'package:meta/meta.dart';
+
 import '../android/android_sdk.dart';
 import '../base/file_system.dart';
+import '../base/logger.dart';
 import '../base/os.dart';
+import '../build_info.dart';
 import '../build_system/build_system.dart';
 import '../commands/build_linux.dart';
 import '../commands/build_macos.dart';
@@ -24,6 +28,7 @@ class BuildCommand extends FlutterCommand {
     required FileSystem fileSystem,
     required BuildSystem buildSystem,
     required OperatingSystemUtils osUtils,
+    required Logger logger,
     required AndroidSdk? androidSdk,
     bool verboseHelp = false,
   }){
@@ -31,32 +36,37 @@ class BuildCommand extends FlutterCommand {
         BuildAarCommand(
           fileSystem: fileSystem,
           androidSdk: androidSdk,
+          logger: logger,
           verboseHelp: verboseHelp,
         )
     );
-    _addSubcommand(BuildApkCommand(verboseHelp: verboseHelp));
+    _addSubcommand(BuildApkCommand(logger: logger, verboseHelp: verboseHelp));
-    _addSubcommand(BuildAppBundleCommand(verboseHelp: verboseHelp));
+    _addSubcommand(BuildAppBundleCommand(logger: logger, verboseHelp: verboseHelp));
-    _addSubcommand(BuildIOSCommand(verboseHelp: verboseHelp));
+    _addSubcommand(BuildIOSCommand(logger: logger, verboseHelp: verboseHelp));
     _addSubcommand(BuildIOSFrameworkCommand(
+      logger: logger,
       buildSystem: buildSystem,
       verboseHelp: verboseHelp,
     ));
     _addSubcommand(BuildMacOSFrameworkCommand(
+      logger: logger,
       buildSystem: buildSystem,
       verboseHelp: verboseHelp,
     ));
-    _addSubcommand(BuildIOSArchiveCommand(verboseHelp: verboseHelp));
+    _addSubcommand(BuildIOSArchiveCommand(logger: logger, verboseHelp: verboseHelp));
-    _addSubcommand(BuildBundleCommand(verboseHelp: verboseHelp));
+    _addSubcommand(BuildBundleCommand(logger: logger, verboseHelp: verboseHelp));
     _addSubcommand(BuildWebCommand(
       fileSystem: fileSystem,
+      logger: logger,
       verboseHelp: verboseHelp,
     ));
-    _addSubcommand(BuildMacosCommand(verboseHelp: verboseHelp));
+    _addSubcommand(BuildMacosCommand(logger: logger, verboseHelp: verboseHelp));
     _addSubcommand(BuildLinuxCommand(
+      logger: logger,
       operatingSystemUtils: osUtils,
       verboseHelp: verboseHelp
     ));
-    _addSubcommand(BuildWindowsCommand(verboseHelp: verboseHelp));
+    _addSubcommand(BuildWindowsCommand(logger: logger, verboseHelp: verboseHelp));
   }
 
   void _addSubcommand(BuildSubCommand command) {
@@ -80,11 +90,36 @@ class BuildCommand extends FlutterCommand {
 
 abstract class BuildSubCommand extends FlutterCommand {
   BuildSubCommand({
+    required Logger logger,
     required bool verboseHelp
-  }) {
+  }): _logger = logger {
     requiresPubspecYaml();
     usesFatalWarningsOption(verboseHelp: verboseHelp);
   }
 
+  final Logger _logger;
+
+  @override
+  bool get reportNullSafety => true;
+
   bool get supported => true;
+
+  /// Display a message describing the current null safety runtime mode
+  /// that was selected.
+  ///
+  /// This is similar to the run message in run_hot.dart
+  @protected
+  void displayNullSafetyMode(BuildInfo buildInfo) {
+    if (buildInfo.nullSafetyMode != NullSafetyMode.sound) {
+      _logger.printStatus('');
+      _logger.printStatus(
+        'Building without sound null safety ⚠️',
+        emphasis: true,
+      );
+      _logger.printStatus(
+        'Dart 3 will only support sound null safety, see https://dart.dev/null-safety',
+      );
+    }
+    _logger.printStatus('');
+  }
 }

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

@@ -17,6 +17,7 @@ import 'build.dart';
 
 class BuildAarCommand extends BuildSubCommand {
   BuildAarCommand({
+    required super.logger,
     required AndroidSdk? androidSdk,
     required FileSystem fileSystem,
     required bool verboseHelp,
@@ -49,6 +50,7 @@ class BuildAarCommand extends BuildSubCommand {
     usesDartDefineOption();
     usesExtraDartFlagOptions(verboseHelp: verboseHelp);
     usesTrackWidgetCreation(verboseHelp: false);
+    addNullSafetyModeOptions(hide: !verboseHelp);
     addEnableExperimentation(hide: !verboseHelp);
     addAndroidSpecificBuildOptions(hide: !verboseHelp);
     argParser
@@ -65,6 +67,9 @@ class BuildAarCommand extends BuildSubCommand {
   @override
   final String name = 'aar';
 
+  @override
+  bool get reportNullSafety => false;
+
   @override
   Future<Set<DevelopmentArtifact>> get requiredArtifacts async => <DevelopmentArtifact>{
     DevelopmentArtifact.androidGenSnapshot,
@@ -132,6 +137,7 @@ class BuildAarCommand extends BuildSubCommand {
       throwToolExit('Please specify a build mode and try again.');
     }
 
+    displayNullSafetyMode(androidBuildInfo.first.buildInfo);
     await androidBuilder?.buildAar(
       project: _getProject(),
       target: targetFile.path,

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

@@ -15,7 +15,7 @@ import 'build.dart';
 
 class BuildApkCommand extends BuildSubCommand {
   BuildApkCommand({
-    bool verboseHelp = false
+    required super.logger, bool verboseHelp = false
   }) : super(verboseHelp: verboseHelp) {
     addTreeShakeIconsFlag();
     usesTargetOption();
@@ -32,6 +32,7 @@ class BuildApkCommand extends BuildSubCommand {
     addBundleSkSLPathOption(hide: !verboseHelp);
     addEnableExperimentation(hide: !verboseHelp);
     addBuildPerformanceFile(hide: !verboseHelp);
+    addNullSafetyModeOptions(hide: !verboseHelp);
     usesAnalyzeSizeFlag();
     addAndroidSpecificBuildOptions(hide: !verboseHelp);
     addMultidexOption();
@@ -110,6 +111,7 @@ class BuildApkCommand extends BuildSubCommand {
       multidexEnabled: boolArg('multidex'),
     );
     validateBuild(androidBuildInfo);
+    displayNullSafetyMode(androidBuildInfo.buildInfo);
     globals.terminal.usesTerminalUi = true;
     await androidBuilder?.buildApk(
       project: FlutterProject.current(),

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

@@ -18,6 +18,7 @@ import 'build.dart';
 
 class BuildAppBundleCommand extends BuildSubCommand {
   BuildAppBundleCommand({
+    required super.logger,
     bool verboseHelp = false,
   }) : super(verboseHelp: verboseHelp) {
     addTreeShakeIconsFlag();
@@ -35,6 +36,7 @@ class BuildAppBundleCommand extends BuildSubCommand {
     addBundleSkSLPathOption(hide: !verboseHelp);
     addBuildPerformanceFile(hide: !verboseHelp);
     usesTrackWidgetCreation(verboseHelp: verboseHelp);
+    addNullSafetyModeOptions(hide: !verboseHelp);
     addEnableExperimentation(hide: !verboseHelp);
     usesAnalyzeSizeFlag();
     addAndroidSpecificBuildOptions(hide: !verboseHelp);
@@ -146,6 +148,7 @@ class BuildAppBundleCommand extends BuildSubCommand {
     }
 
     validateBuild(androidBuildInfo);
+    displayNullSafetyMode(androidBuildInfo.buildInfo);
     globals.terminal.usesTerminalUi = true;
     await androidBuilder?.buildAab(
       project: FlutterProject.current(),

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

@@ -15,6 +15,7 @@ import 'build.dart';
 
 class BuildBundleCommand extends BuildSubCommand {
   BuildBundleCommand({
+    required super.logger,
     bool verboseHelp = false,
     BundleBuilder? bundleBuilder,
   }) :  _bundleBuilder = bundleBuilder ?? BundleBuilder(), super(verboseHelp: verboseHelp) {
@@ -125,9 +126,12 @@ class BuildBundleCommand extends BuildSubCommand {
         break;
     }
 
+    final BuildInfo buildInfo = await getBuildInfo();
+    displayNullSafetyMode(buildInfo);
+
     await _bundleBuilder.build(
       platform: platform,
-      buildInfo: await getBuildInfo(),
+      buildInfo: buildInfo,
       mainPath: targetFile,
       depfilePath: stringArg('depfile'),
       assetDirPath: stringArg('asset-dir'),

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

@@ -26,7 +26,7 @@ import 'build.dart';
 /// Builds an .app for an iOS app to be used for local testing on an iOS device
 /// or simulator. Can only be run on a macOS host.
 class BuildIOSCommand extends _BuildIOSSubCommand {
-  BuildIOSCommand({ required super.verboseHelp }) {
+  BuildIOSCommand({ required super.logger, required super.verboseHelp }) {
     argParser
       ..addFlag('config-only',
         help: 'Update the project configuration without performing a build. '
@@ -91,7 +91,7 @@ class _ImageAssetFileKey {
 ///
 /// Can only be run on a macOS host.
 class BuildIOSArchiveCommand extends _BuildIOSSubCommand {
-  BuildIOSArchiveCommand({ required super.verboseHelp }) {
+  BuildIOSArchiveCommand({required super.logger, required super.verboseHelp}) {
     argParser.addOption(
       'export-method',
       defaultsTo: 'app-store',
@@ -412,6 +412,8 @@ class BuildIOSArchiveCommand extends _BuildIOSSubCommand {
 
   @override
   Future<FlutterCommandResult> runCommand() async {
+    final BuildInfo buildInfo = await cachedBuildInfo;
+    displayNullSafetyMode(buildInfo);
     final FlutterCommandResult xcarchiveResult = await super.runCommand();
 
     final List<ValidationResult?> validationResults = <ValidationResult?>[];
@@ -555,6 +557,7 @@ class BuildIOSArchiveCommand extends _BuildIOSSubCommand {
 
 abstract class _BuildIOSSubCommand extends BuildSubCommand {
   _BuildIOSSubCommand({
+    required super.logger,
     required bool verboseHelp
   }) : super(verboseHelp: verboseHelp) {
     addTreeShakeIconsFlag();
@@ -571,6 +574,7 @@ abstract class _BuildIOSSubCommand extends BuildSubCommand {
     addEnableExperimentation(hide: !verboseHelp);
     addBuildPerformanceFile(hide: !verboseHelp);
     addBundleSkSLPathOption(hide: !verboseHelp);
+    addNullSafetyModeOptions(hide: !verboseHelp);
     usesAnalyzeSizeFlag();
     argParser.addFlag('codesign',
       defaultsTo: true,

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

@@ -33,6 +33,7 @@ abstract class BuildFrameworkCommand extends BuildSubCommand {
     required bool verboseHelp,
     Cache? cache,
     Platform? platform,
+    required super.logger,
   }) : _injectedFlutterVersion = flutterVersion,
        _buildSystem = buildSystem,
        _injectedCache = cache,
@@ -45,6 +46,7 @@ abstract class BuildFrameworkCommand extends BuildSubCommand {
     addSplitDebugInfoOption();
     addDartObfuscationOption();
     usesExtraDartFlagOptions(verboseHelp: verboseHelp);
+    addNullSafetyModeOptions(hide: !verboseHelp);
     addEnableExperimentation(hide: !verboseHelp);
 
     argParser
@@ -98,6 +100,9 @@ abstract class BuildFrameworkCommand extends BuildSubCommand {
   FlutterVersion get flutterVersion => _injectedFlutterVersion ?? globals.flutterVersion;
   final FlutterVersion? _injectedFlutterVersion;
 
+  @override
+  bool get reportNullSafety => false;
+
   @protected
   late final FlutterProject project = FlutterProject.current();
 
@@ -172,6 +177,7 @@ abstract class BuildFrameworkCommand extends BuildSubCommand {
 /// managers.
 class BuildIOSFrameworkCommand extends BuildFrameworkCommand {
   BuildIOSFrameworkCommand({
+    required super.logger,
     super.flutterVersion,
     required super.buildSystem,
     required bool verboseHelp,
@@ -230,6 +236,7 @@ class BuildIOSFrameworkCommand extends BuildFrameworkCommand {
 
     final Directory outputDirectory = globals.fs.directory(globals.fs.path.absolute(globals.fs.path.normalize(outputArgument)));
     final List<BuildInfo> buildInfos = await getBuildInfos();
+    displayNullSafetyMode(buildInfos.first);
     for (final BuildInfo buildInfo in buildInfos) {
       final String? productBundleIdentifier = await project.ios.productBundleIdentifier(buildInfo);
       globals.printStatus('Building frameworks for $productBundleIdentifier in ${getNameForBuildMode(buildInfo.mode)} mode...');

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

@@ -17,6 +17,7 @@ import 'build.dart';
 /// A command to build a linux desktop target through a build shell script.
 class BuildLinuxCommand extends BuildSubCommand {
   BuildLinuxCommand({
+    required super.logger,
     required OperatingSystemUtils operatingSystemUtils,
     bool verboseHelp = false,
   }) : _operatingSystemUtils = operatingSystemUtils,
@@ -81,6 +82,7 @@ class BuildLinuxCommand extends BuildSubCommand {
       throwToolExit(
           'Cross-build from Linux x64 host to Linux arm64 target is not currently supported.');
     }
+    displayNullSafetyMode(buildInfo);
     await buildLinux(
       flutterProject.linux,
       buildInfo,

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

@@ -16,6 +16,7 @@ import 'build.dart';
 /// A command to build a macOS desktop target through a build shell script.
 class BuildMacosCommand extends BuildSubCommand {
   BuildMacosCommand({
+    required super.logger,
     required bool verboseHelp,
   }) : super(verboseHelp: verboseHelp) {
     addCommonDesktopBuildOptions(verboseHelp: verboseHelp);
@@ -57,6 +58,7 @@ class BuildMacosCommand extends BuildSubCommand {
     if (!supported) {
       throwToolExit('"build macos" only supported on macOS hosts.');
     }
+    displayNullSafetyMode(buildInfo);
     await buildMacOS(
       flutterProject: flutterProject,
       buildInfo: buildInfo,

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

@@ -29,6 +29,7 @@ class BuildMacOSFrameworkCommand extends BuildFrameworkCommand {
     super.flutterVersion,
     required super.buildSystem,
     required super.verboseHelp,
+    required super.logger,
     super.cache,
     super.platform,
   });
@@ -68,6 +69,7 @@ class BuildMacOSFrameworkCommand extends BuildFrameworkCommand {
         globals.fs.directory(globals.fs.path.absolute(globals.fs.path.normalize(outputArgument)));
 
     final List<BuildInfo> buildInfos = await getBuildInfos();
+    displayNullSafetyMode(buildInfos.first);
 
     for (final BuildInfo buildInfo in buildInfos) {
       globals.printStatus('Building macOS frameworks in ${getNameForBuildMode(buildInfo.mode)} mode...');

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

@@ -16,6 +16,7 @@ import 'build.dart';
 
 class BuildWebCommand extends BuildSubCommand {
   BuildWebCommand({
+    required super.logger,
     required FileSystem fileSystem,
     required bool verboseHelp,
   }) : _fileSystem = fileSystem, super(verboseHelp: verboseHelp) {
@@ -28,6 +29,7 @@ class BuildWebCommand extends BuildSubCommand {
     addBuildModeFlags(verboseHelp: verboseHelp, excludeDebug: true);
     usesDartDefineOption();
     addEnableExperimentation(hide: !verboseHelp);
+    addNullSafetyModeOptions(hide: !verboseHelp);
     addNativeNullAssertions();
 
     //
@@ -164,6 +166,7 @@ class BuildWebCommand extends BuildSubCommand {
     // valid approaches for setting output directory of build artifacts
     final String? outputDirectoryPath = stringArg('output');
 
+    displayNullSafetyMode(buildInfo);
     await buildWeb(
       flutterProject,
       target,

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

@@ -19,6 +19,7 @@ import 'build.dart';
 /// A command to build a windows desktop target through a build shell script.
 class BuildWindowsCommand extends BuildSubCommand {
   BuildWindowsCommand({
+    required super.logger,
     bool verboseHelp = false,
   }) : super(verboseHelp: verboseHelp) {
     addCommonDesktopBuildOptions(verboseHelp: verboseHelp);
@@ -51,6 +52,7 @@ class BuildWindowsCommand extends BuildSubCommand {
     if (!globals.platform.isWindows) {
       throwToolExit('"build windows" only supported on Windows hosts.');
     }
+    displayNullSafetyMode(buildInfo);
     await buildWindows(
       flutterProject.windows,
       buildInfo,

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

@@ -173,6 +173,7 @@ abstract class RunCommandBase extends FlutterCommand with DeviceBasedDevelopment
     usesIpv6Flag(verboseHelp: verboseHelp);
     usesPubOption();
     usesTrackWidgetCreation(verboseHelp: verboseHelp);
+    addNullSafetyModeOptions(hide: !verboseHelp);
     usesDeviceUserOption();
     usesDeviceTimeoutOption();
     addDdsOptions(verboseHelp: verboseHelp);
@@ -197,6 +198,9 @@ abstract class RunCommandBase extends FlutterCommand with DeviceBasedDevelopment
   bool get uninstallFirst => boolArg('uninstall-first');
   bool get enableEmbedderApi => boolArg('enable-embedder-api');
 
+  @override
+  bool get reportNullSafety => true;
+
   /// Whether to start the application paused by default.
   bool get startPausedDefault;
 
@@ -274,6 +278,7 @@ abstract class RunCommandBase extends FlutterCommand with DeviceBasedDevelopment
         fastStart: argParser.options.containsKey('fast-start')
           && boolArg('fast-start')
           && !runningWithPrebuiltApplication,
+        nullAssertions: boolArg('null-assertions'),
         nativeNullAssertions: boolArg('native-null-assertions'),
         enableImpeller: enableImpeller,
         uninstallFirst: uninstallFirst,

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

@@ -67,6 +67,7 @@ class TestCommand extends FlutterCommand with DeviceBasedDevelopmentArtifacts {
   }) {
     requiresPubspecYaml();
     usesPubOption();
+    addNullSafetyModeOptions(hide: !verboseHelp);
     usesTrackWidgetCreation(verboseHelp: verboseHelp);
     addEnableExperimentation(hide: !verboseHelp);
     usesDartDefineOption();
@@ -419,6 +420,7 @@ class TestCommand extends FlutterCommand with DeviceBasedDevelopmentArtifacts {
       // On iOS >=14, keeping this enabled will leave a prompt on the screen.
       disablePortPublication: true,
       enableDds: enableDds,
+      nullAssertions: boolArg(FlutterOptions.kNullAssertions),
     );
 
     Device? integrationTestDevice;

packages/flutter_tools/lib/src/device.dart

@@ -916,6 +916,7 @@ class DebuggingOptions {
     this.webLaunchUrl,
     this.vmserviceOutFile,
     this.fastStart = false,
+    this.nullAssertions = false,
     this.nativeNullAssertions = false,
     this.enableImpeller = false,
     this.uninstallFirst = false,
@@ -966,6 +967,7 @@ class DebuggingOptions {
       vmserviceOutFile = null,
       fastStart = false,
       webEnableExpressionEvaluation = false,
+      nullAssertions = false,
       nativeNullAssertions = false,
       serveObservatory = false;
 
@@ -1008,6 +1010,7 @@ class DebuggingOptions {
     required this.webLaunchUrl,
     required this.vmserviceOutFile,
     required this.fastStart,
+    required this.nullAssertions,
     required this.nativeNullAssertions,
     required this.enableImpeller,
     required this.uninstallFirst,
@@ -1081,6 +1084,8 @@ class DebuggingOptions {
   final String? vmserviceOutFile;
   final bool fastStart;
 
+  final bool nullAssertions;
+
   /// Additional null runtime checks inserted for web applications.
   ///
   /// See also:
@@ -1175,6 +1180,7 @@ class DebuggingOptions {
     'webLaunchUrl': webLaunchUrl,
     'vmserviceOutFile': vmserviceOutFile,
     'fastStart': fastStart,
+    'nullAssertions': nullAssertions,
     'nativeNullAssertions': nativeNullAssertions,
     'enableImpeller': enableImpeller,
     'serveObservatory': serveObservatory,
@@ -1222,6 +1228,7 @@ class DebuggingOptions {
       webLaunchUrl: json['webLaunchUrl'] as String?,
       vmserviceOutFile: json['vmserviceOutFile'] as String?,
       fastStart: json['fastStart']! as bool,
+      nullAssertions: json['nullAssertions']! as bool,
       nativeNullAssertions: json['nativeNullAssertions']! as bool,
       enableImpeller: (json['enableImpeller'] as bool?) ?? false,
       uninstallFirst: (json['uninstallFirst'] as bool?) ?? false,
@@ -1303,9 +1310,13 @@ class NoOpDeviceLogReader implements DeviceLogReader {
   void dispose() { }
 }
 
+/// Append --null_assertions to any existing Dart VM flags if
+/// [debuggingOptions.nullAssertions] is true.
 String computeDartVmFlags(DebuggingOptions debuggingOptions) {
-  if (debuggingOptions.dartFlags.isNotEmpty) {
+  return <String>[
-    return debuggingOptions.dartFlags;
+    if (debuggingOptions.dartFlags.isNotEmpty)
-  }
+      debuggingOptions.dartFlags,
-  return '';
+    if (debuggingOptions.nullAssertions)
+      '--null_assertions',
+  ].join(',');
 }

packages/flutter_tools/lib/src/fuchsia/fuchsia_kernel_compiler.dart

@@ -48,6 +48,7 @@ class FuchsiaKernelCompiler {
       throwToolExit('Fuchsia platform file not found at "$platformDill"');
     }
     List<String> flags = <String>[
+      '--no-sound-null-safety',
       '--target',
       'flutter_runner',
       '--platform',

packages/flutter_tools/lib/src/isolated/devfs_web.dart

@@ -133,6 +133,7 @@ class WebAssetServer implements AssetReader {
     this.internetAddress,
     this._modules,
     this._digests,
+    this._nullSafetyMode,
   ) : basePath = _getIndexHtml().getBaseHref();
 
   // Fallback to "application/octet-stream" on null which
@@ -187,7 +188,8 @@ class WebAssetServer implements AssetReader {
     bool enableDwds,
     bool enableDds,
     Uri entrypoint,
-    ExpressionCompiler? expressionCompiler, {
+    ExpressionCompiler? expressionCompiler,
+    NullSafetyMode nullSafetyMode, {
     bool testMode = false,
     DwdsLauncher dwdsLauncher = Dwds.start,
   }) async {
@@ -224,6 +226,7 @@ class WebAssetServer implements AssetReader {
       address,
       modules,
       digests,
+      nullSafetyMode,
     );
     if (testMode) {
       return server;
@@ -316,6 +319,7 @@ class WebAssetServer implements AssetReader {
     return server;
   }
 
+  final NullSafetyMode _nullSafetyMode;
   final HttpServer _httpServer;
   final WebMemoryFS _webMemoryFS = WebMemoryFS();
   final PackageConfig _packages;
@@ -572,12 +576,12 @@ class WebAssetServer implements AssetReader {
 
   File get _resolveDartSdkJsFile =>
       globals.fs.file(globals.artifacts!.getHostArtifact(
-          kDartSdkJsArtifactMap[webRenderer]!
+          kDartSdkJsArtifactMap[webRenderer]![_nullSafetyMode]!
       ));
 
   File get _resolveDartSdkJsMapFile =>
     globals.fs.file(globals.artifacts!.getHostArtifact(
-        kDartSdkJsMapArtifactMap[webRenderer]!
+        kDartSdkJsMapArtifactMap[webRenderer]![_nullSafetyMode]!
     ));
 
   @override
@@ -646,7 +650,9 @@ class WebDevFS implements DevFS {
     required this.entrypoint,
     required this.expressionCompiler,
     required this.chromiumLauncher,
+    required this.nullAssertions,
     required this.nativeNullAssertions,
+    required this.nullSafetyMode,
     this.testMode = false,
   }) : _port = port;
 
@@ -663,8 +669,10 @@ class WebDevFS implements DevFS {
   final bool testMode;
   final ExpressionCompiler? expressionCompiler;
   final ChromiumLauncher? chromiumLauncher;
+  final bool nullAssertions;
   final bool nativeNullAssertions;
   final int? _port;
+  final NullSafetyMode nullSafetyMode;
 
   late WebAssetServer webAssetServer;
 
@@ -760,6 +768,7 @@ class WebDevFS implements DevFS {
       enableDds,
       entrypoint,
       expressionCompiler,
+      nullSafetyMode,
       testMode: testMode,
     );
 
@@ -848,6 +857,7 @@ class WebDevFS implements DevFS {
         'main_module.bootstrap.js',
         generateMainModule(
           entrypoint: entrypoint,
+          nullAssertions: nullAssertions,
           nativeNullAssertions: nativeNullAssertions,
         ),
       );

packages/flutter_tools/lib/src/isolated/resident_web_runner.dart

@@ -274,6 +274,8 @@ class ResidentWebRunner extends ResidentRunner {
           entrypoint: _fileSystem.file(target).uri,
           expressionCompiler: expressionCompiler,
           chromiumLauncher: _chromiumLauncher,
+          nullAssertions: debuggingOptions.nullAssertions,
+          nullSafetyMode: debuggingOptions.buildInfo.nullSafetyMode,
           nativeNullAssertions: debuggingOptions.nativeNullAssertions,
         );
         final Uri url = await device!.devFS!.create();
@@ -601,6 +603,16 @@ class ResidentWebRunner extends ResidentRunner {
           ..writeAsStringSync(websocketUri.toString());
       }
       _logger.printStatus('Debug service listening on $websocketUri');
+      if (debuggingOptions.buildInfo.nullSafetyMode !=  NullSafetyMode.sound) {
+        _logger.printStatus('');
+        _logger.printStatus(
+          'Running without sound null safety ⚠️',
+          emphasis: true,
+        );
+        _logger.printStatus(
+          'Dart 3 will only support sound null safety, see https://dart.dev/null-safety',
+        );
+      }
     }
     appStartedCompleter?.complete();
     connectionInfoCompleter?.complete(DebugConnectionInfo(wsUri: websocketUri));

packages/flutter_tools/lib/src/reporting/custom_dimensions.dart

@@ -59,6 +59,8 @@ class CustomDimensions {
     this.commandPackagesAndroidEmbeddingVersion,
     this.nullSafety,
     this.fastReassemble,
+    this.nullSafeMigratedLibraries,
+    this.nullSafeTotalLibraries,
     this.hotEventCompileTimeInMs,
     this.hotEventFindInvalidatedTimeInMs,
     this.hotEventScannedSourcesCount,
@@ -116,8 +118,8 @@ class CustomDimensions {
   final String? commandPackagesAndroidEmbeddingVersion;  // cd46
   final bool? nullSafety;  // cd47
   final bool? fastReassemble;  // cd48
-  // final int? nullSafeMigratedLibraries;  // cd49 - deprecated
+  final int? nullSafeMigratedLibraries;  // cd49
-  // final int? nullSafeTotalLibraries;  // cd50 - deprecated
+  final int? nullSafeTotalLibraries;  // cd50
   final int? hotEventCompileTimeInMs;  // cd 51
   final int? hotEventFindInvalidatedTimeInMs;  // cd 52
   final int? hotEventScannedSourcesCount;  // cd 53
@@ -176,6 +178,8 @@ class CustomDimensions {
       if (commandPackagesAndroidEmbeddingVersion != null) cdKey(CustomDimensionsEnum.commandPackagesAndroidEmbeddingVersion): commandPackagesAndroidEmbeddingVersion.toString(),
       if (nullSafety != null) cdKey(CustomDimensionsEnum.nullSafety): nullSafety.toString(),
       if (fastReassemble != null) cdKey(CustomDimensionsEnum.fastReassemble): fastReassemble.toString(),
+      if (nullSafeMigratedLibraries != null) cdKey(CustomDimensionsEnum.nullSafeMigratedLibraries): nullSafeMigratedLibraries.toString(),
+      if (nullSafeTotalLibraries != null) cdKey(CustomDimensionsEnum.nullSafeTotalLibraries): nullSafeTotalLibraries.toString(),
       if (hotEventCompileTimeInMs != null) cdKey(CustomDimensionsEnum.hotEventCompileTimeInMs): hotEventCompileTimeInMs.toString(),
       if (hotEventFindInvalidatedTimeInMs != null) cdKey(CustomDimensionsEnum.hotEventFindInvalidatedTimeInMs): hotEventFindInvalidatedTimeInMs.toString(),
       if (hotEventScannedSourcesCount != null) cdKey(CustomDimensionsEnum.hotEventScannedSourcesCount): hotEventScannedSourcesCount.toString(),
@@ -241,6 +245,8 @@ class CustomDimensions {
       commandPackagesAndroidEmbeddingVersion: other.commandPackagesAndroidEmbeddingVersion ?? commandPackagesAndroidEmbeddingVersion,
       nullSafety: other.nullSafety ?? nullSafety,
       fastReassemble: other.fastReassemble ?? fastReassemble,
+      nullSafeMigratedLibraries: other.nullSafeMigratedLibraries ?? nullSafeMigratedLibraries,
+      nullSafeTotalLibraries: other.nullSafeTotalLibraries ?? nullSafeTotalLibraries,
       hotEventCompileTimeInMs: other.hotEventCompileTimeInMs ?? hotEventCompileTimeInMs,
       hotEventFindInvalidatedTimeInMs: other.hotEventFindInvalidatedTimeInMs ?? hotEventFindInvalidatedTimeInMs,
       hotEventScannedSourcesCount: other.hotEventScannedSourcesCount ?? hotEventScannedSourcesCount,
@@ -300,6 +306,8 @@ class CustomDimensions {
       commandPackagesAndroidEmbeddingVersion: _extractString(map, CustomDimensionsEnum.commandPackagesAndroidEmbeddingVersion),
       nullSafety: _extractBool(map, CustomDimensionsEnum.nullSafety),
       fastReassemble: _extractBool(map, CustomDimensionsEnum.fastReassemble),
+      nullSafeMigratedLibraries: _extractInt(map, CustomDimensionsEnum.nullSafeMigratedLibraries),
+      nullSafeTotalLibraries: _extractInt(map, CustomDimensionsEnum.nullSafeTotalLibraries),
       hotEventCompileTimeInMs: _extractInt(map, CustomDimensionsEnum.hotEventCompileTimeInMs),
       hotEventFindInvalidatedTimeInMs: _extractInt(map, CustomDimensionsEnum.hotEventFindInvalidatedTimeInMs),
       hotEventScannedSourcesCount: _extractInt(map, CustomDimensionsEnum.hotEventScannedSourcesCount),
@@ -385,8 +393,8 @@ enum CustomDimensionsEnum {
   commandPackagesAndroidEmbeddingVersion,  // cd46
   nullSafety,  // cd47
   fastReassemble,  // cd48
-  nullSafeMigratedLibraries,  // cd49 - deprecated
+  nullSafeMigratedLibraries,  // cd49
-  nullSafeTotalLibraries,  // cd50 - deprecated
+  nullSafeTotalLibraries,  // cd50
   hotEventCompileTimeInMs,  // cd51
   hotEventFindInvalidatedTimeInMs,  // cd52
   hotEventScannedSourcesCount,  // cd53

packages/flutter_tools/lib/src/reporting/events.dart

@@ -248,3 +248,67 @@ class CodeSizeEvent extends UsageEvent {
 class ErrorHandlingEvent extends UsageEvent {
   ErrorHandlingEvent(String parameter) : super('error-handling', parameter, flutterUsage: globals.flutterUsage);
 }
+
+/// Emit various null safety analytic events.
+///
+/// 1. The current null safety runtime mode.
+/// 2. The number of packages that are migrated, along with the total number of packages
+/// 3. The main packages language version.
+class NullSafetyAnalysisEvent implements UsageEvent {
+  NullSafetyAnalysisEvent(
+    this.packageConfig,
+    this.nullSafetyMode,
+    this.currentPackage,
+    this.flutterUsage,
+  );
+
+  /// The category for analytics events related to null safety.
+  static const String kNullSafetyCategory = 'null-safety';
+
+  final PackageConfig packageConfig;
+  final NullSafetyMode nullSafetyMode;
+  final String currentPackage;
+  @override
+  final Usage flutterUsage;
+
+  @override
+  void send() {
+    if (packageConfig.packages.isEmpty) {
+      return;
+    }
+    int migrated = 0;
+    LanguageVersion? languageVersion;
+    for (final Package package in packageConfig.packages) {
+      final LanguageVersion? packageLanguageVersion = package.languageVersion;
+      if (package.name == currentPackage) {
+        languageVersion = packageLanguageVersion;
+      }
+      if (packageLanguageVersion != null &&
+          packageLanguageVersion.major >= nullSafeVersion.major &&
+          packageLanguageVersion.minor >= nullSafeVersion.minor) {
+        migrated += 1;
+      }
+    }
+    flutterUsage.sendEvent(kNullSafetyCategory, 'runtime-mode', label: nullSafetyMode.toString());
+    flutterUsage.sendEvent(kNullSafetyCategory, 'stats', parameters: CustomDimensions(
+      nullSafeMigratedLibraries: migrated,
+      nullSafeTotalLibraries: packageConfig.packages.length,
+    ));
+    if (languageVersion != null) {
+      final String formattedVersion = '${languageVersion.major}.${languageVersion.minor}';
+      flutterUsage.sendEvent(kNullSafetyCategory, 'language-version', label: formattedVersion);
+    }
+  }
+
+  @override
+  String get category => kNullSafetyCategory;
+
+  @override
+  String get label => throw UnsupportedError('');
+
+  @override
+  String get parameter => throw UnsupportedError('');
+
+  @override
+  int get value => throw UnsupportedError('');
+}

packages/flutter_tools/lib/src/reporting/reporting.dart

@@ -8,11 +8,14 @@ import 'dart:async';
 
 import 'package:file/file.dart';
 import 'package:meta/meta.dart';
+import 'package:package_config/package_config.dart';
 import 'package:usage/usage_io.dart';
 
 import '../base/error_handling_io.dart';
 import '../base/file_system.dart';
 import '../base/time.dart';
+import '../build_info.dart';
+import '../dart/language_version.dart';
 import '../doctor_validator.dart';
 import '../features.dart';
 import '../globals.dart' as globals;

packages/flutter_tools/lib/src/resident_runner.dart

@@ -118,8 +118,21 @@ class FlutterDevice {
     // used to file a bug, but the compiler will still start up correctly.
     if (targetPlatform == TargetPlatform.web_javascript) {
       // TODO(zanderso): consistently provide these flags across platforms.
-      const String platformDillName = 'ddc_outline_sound.dill';
+      final String platformDillName;
       final List<String> extraFrontEndOptions = List<String>.of(buildInfo.extraFrontEndOptions);
+      if (buildInfo.nullSafetyMode == NullSafetyMode.unsound) {
+        platformDillName = 'ddc_outline.dill';
+        if (!extraFrontEndOptions.contains('--no-sound-null-safety')) {
+          extraFrontEndOptions.add('--no-sound-null-safety');
+        }
+      } else if (buildInfo.nullSafetyMode == NullSafetyMode.sound) {
+        platformDillName = 'ddc_outline_sound.dill';
+        if (!extraFrontEndOptions.contains('--sound-null-safety')) {
+          extraFrontEndOptions.add('--sound-null-safety');
+        }
+      } else {
+        throw StateError('Expected buildInfo.nullSafetyMode to be one of unsound or sound, got ${buildInfo.nullSafetyMode}');
+      }
 
       final String platformDillPath = globals.fs.path.join(
         getWebPlatformBinariesDirectory(globals.artifacts!, buildInfo.webRenderer).path,

packages/flutter_tools/lib/src/run_hot.dart

@@ -1039,6 +1039,16 @@ class HotRunner extends ResidentRunner {
     }
     commandHelp.c.print();
     commandHelp.q.print();
+    if (debuggingOptions.buildInfo.nullSafetyMode !=  NullSafetyMode.sound) {
+      globals.printStatus('');
+      globals.printStatus(
+        'Running without sound null safety ⚠️',
+        emphasis: true,
+      );
+      globals.printStatus(
+        'Dart 3 will only support sound null safety, see https://dart.dev/null-safety',
+      );
+    }
     globals.printStatus('');
     printDebuggerList();
   }

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

@@ -21,6 +21,7 @@ import '../bundle.dart' as bundle;
 import '../cache.dart';
 import '../convert.dart';
 import '../dart/generate_synthetic_packages.dart';
+import '../dart/language_version.dart';
 import '../dart/package_map.dart';
 import '../dart/pub.dart';
 import '../device.dart';
@@ -109,10 +110,12 @@ class FlutterOptions {
   static const String kDartDefineFromFileOption = 'dart-define-from-file';
   static const String kBundleSkSLPathOption = 'bundle-sksl-path';
   static const String kPerformanceMeasurementFile = 'performance-measurement-file';
+  static const String kNullSafety = 'sound-null-safety';
   static const String kDeviceUser = 'device-user';
   static const String kDeviceTimeout = 'device-timeout';
   static const String kAnalyzeSize = 'analyze-size';
   static const String kCodeSizeDirectory = 'code-size-directory';
+  static const String kNullAssertions = 'null-assertions';
   static const String kAndroidGradleDaemon = 'android-gradle-daemon';
   static const String kDeferredComponents = 'deferred-components';
   static const String kAndroidProjectArgs = 'android-project-arg';
@@ -692,6 +695,9 @@ abstract class FlutterCommand extends Command<void> {
   /// Whether it is safe for this command to use a cached pub invocation.
   bool get cachePubGet => true;
 
+  /// Whether this command should report null safety analytics.
+  bool get reportNullSafety => false;
+
   late final Duration? deviceDiscoveryTimeout = () {
     if ((argResults?.options.contains(FlutterOptions.kDeviceTimeout) ?? false)
         && (argResults?.wasParsed(FlutterOptions.kDeviceTimeout) ?? false)) {
@@ -800,6 +806,25 @@ abstract class FlutterCommand extends Command<void> {
     );
   }
 
+  void addNullSafetyModeOptions({ required bool hide }) {
+    argParser.addFlag(FlutterOptions.kNullSafety,
+      help:
+        'Whether to override the inferred null safety mode. This allows null-safe '
+        'libraries to depend on un-migrated (non-null safe) libraries. By default, '
+        'Flutter mobile & desktop applications will attempt to run at the null safety '
+        'level of their entrypoint library (usually lib/main.dart). Flutter web '
+        'applications will default to sound null-safety, unless specifically configured.',
+      defaultsTo: true,
+      hide: hide,
+    );
+    argParser.addFlag(FlutterOptions.kNullAssertions,
+      help:
+        'Perform additional null assertions on the boundaries of migrated and '
+        'un-migrated code. This setting is not currently supported on desktop '
+        'devices.'
+    );
+  }
+
   /// Enables support for the hidden options --extra-front-end-options and
   /// --extra-gen-snapshot-options.
   void usesExtraDartFlagOptions({ required bool verboseHelp }) {
@@ -928,6 +953,7 @@ abstract class FlutterCommand extends Command<void> {
     addBundleSkSLPathOption(hide: !verboseHelp);
     addDartObfuscationOption();
     addEnableExperimentation(hide: !verboseHelp);
+    addNullSafetyModeOptions(hide: !verboseHelp);
     addSplitDebugInfoOption();
     addTreeShakeIconsFlag();
     usesAnalyzeSizeFlag();
@@ -1085,6 +1111,44 @@ abstract class FlutterCommand extends Command<void> {
       codeSizeDirectory = directory.path;
     }
 
+    NullSafetyMode nullSafetyMode = NullSafetyMode.sound;
+    if (argParser.options.containsKey(FlutterOptions.kNullSafety)) {
+      // Explicitly check for `true` and `false` so that `null` results in not
+      // passing a flag. Examine the entrypoint file to determine if it
+      // is opted in or out.
+      final bool wasNullSafetyFlagParsed = argResults?.wasParsed(FlutterOptions.kNullSafety) ?? false;
+      if (!wasNullSafetyFlagParsed && (argParser.options.containsKey('target') || forcedTargetFile != null)) {
+        final File entrypointFile = forcedTargetFile ?? globals.fs.file(targetFile);
+        final LanguageVersion languageVersion = determineLanguageVersion(
+          entrypointFile,
+          packageConfig.packageOf(entrypointFile.absolute.uri),
+          Cache.flutterRoot!,
+        );
+        // Extra frontend options are only provided if explicitly
+        // requested.
+        if ((languageVersion.major > nullSafeVersion.major) ||
+            (languageVersion.major == nullSafeVersion.major && languageVersion.minor >= nullSafeVersion.minor)) {
+          nullSafetyMode = NullSafetyMode.sound;
+        } else {
+          throwToolExit(
+            'This application does not support sound null-safety (its language version is $languageVersion).\n'
+            'To build this application, you must provide the CLI flag --no-sound-null-safety. Dart 3 will only '
+            'support sound null safety, see https://dart.dev/null-safety.',
+          );
+        }
+      } else if (!wasNullSafetyFlagParsed) {
+        // This mode is only used for commands which do not build a single target like
+        // 'flutter test'.
+        nullSafetyMode = NullSafetyMode.autodetect;
+      } else if (boolArg(FlutterOptions.kNullSafety)) {
+        nullSafetyMode = NullSafetyMode.sound;
+        extraFrontEndOptions.add('--sound-null-safety');
+      } else {
+        nullSafetyMode = NullSafetyMode.unsound;
+        extraFrontEndOptions.add('--no-sound-null-safety');
+      }
+    }
+
     final bool dartObfuscation = argParser.options.containsKey(FlutterOptions.kDartObfuscationOption)
       && boolArg(FlutterOptions.kDartObfuscationOption);
 
@@ -1168,6 +1232,7 @@ abstract class FlutterCommand extends Command<void> {
       performanceMeasurementFile: performanceMeasurementFile,
       dartDefineConfigJsonMap: defineConfigJsonMap,
       packagesPath: packagesPath ?? globals.fs.path.absolute('.dart_tool', 'package_config.json'),
+      nullSafetyMode: nullSafetyMode,
       codeSizeDirectory: codeSizeDirectory,
       androidGradleDaemon: androidGradleDaemon,
       packageConfig: packageConfig,
@@ -1427,6 +1492,9 @@ abstract class FlutterCommand extends Command<void> {
         checkUpToDate: cachePubGet,
       );
       await project.regeneratePlatformSpecificTooling();
+      if (reportNullSafety) {
+        await _sendNullSafetyAnalyticsEvents(project);
+      }
     }
 
     setupApplicationPackages();
@@ -1440,6 +1508,16 @@ abstract class FlutterCommand extends Command<void> {
     return runCommand();
   }
 
+  Future<void> _sendNullSafetyAnalyticsEvents(FlutterProject project) async {
+    final BuildInfo buildInfo = await getBuildInfo();
+    NullSafetyAnalysisEvent(
+      buildInfo.packageConfig,
+      buildInfo.nullSafetyMode,
+      project.manifest.appName,
+      globals.flutterUsage,
+    ).send();
+  }
+
   /// The set of development artifacts required for this command.
   ///
   /// Defaults to an empty set. Including [DevelopmentArtifact.universal] is

packages/flutter_tools/lib/src/test/flutter_tester_device.dart

@@ -119,6 +119,8 @@ class FlutterTesterTestDevice extends TestDevice {
       '--packages=${debuggingOptions.buildInfo.packagesPath}',
       if (testAssetDirectory != null)
         '--flutter-assets-dir=$testAssetDirectory',
+      if (debuggingOptions.nullAssertions)
+        '--dart-flags=--null_assertions',
       ...debuggingOptions.dartEntrypointArgs,
       entrypointPath,
     ];

packages/flutter_tools/lib/src/test/flutter_web_platform.dart

@@ -42,6 +42,7 @@ class FlutterWebPlatform extends PlatformPlugin {
     FlutterProject? flutterProject,
     String? shellPath,
     this.updateGoldens,
+    this.nullAssertions,
     required this.buildInfo,
     required this.webMemoryFS,
     required FileSystem fileSystem,
@@ -91,6 +92,7 @@ class FlutterWebPlatform extends PlatformPlugin {
   final Logger _logger;
   final Artifacts? _artifacts;
   final bool? updateGoldens;
+  final bool? nullAssertions;
   final OneOffHandler _webSocketHandler = OneOffHandler();
   final AsyncMemoizer<void> _closeMemo = AsyncMemoizer<void>();
   final String _root;
@@ -108,6 +110,7 @@ class FlutterWebPlatform extends PlatformPlugin {
     String? shellPath,
     bool updateGoldens = false,
     bool pauseAfterLoad = false,
+    bool nullAssertions = false,
     required BuildInfo buildInfo,
     required WebMemoryFS webMemoryFS,
     required FileSystem fileSystem,
@@ -142,6 +145,7 @@ class FlutterWebPlatform extends PlatformPlugin {
       chromiumLauncher: chromiumLauncher,
       artifacts: artifacts,
       logger: logger,
+      nullAssertions: nullAssertions,
       processManager: processManager,
       testTimeRecorder: testTimeRecorder,
     );
@@ -158,6 +162,12 @@ class FlutterWebPlatform extends PlatformPlugin {
       : WebRendererMode.html;
   }
 
+  NullSafetyMode get _nullSafetyMode {
+    return buildInfo.nullSafetyMode == NullSafetyMode.sound
+      ? NullSafetyMode.sound
+      : NullSafetyMode.unsound;
+  }
+
   final Configuration _config;
   final shelf.Server _server;
   Uri get url => _server.url;
@@ -190,10 +200,10 @@ class FlutterWebPlatform extends PlatformPlugin {
   ));
 
   File get _dartSdk => _fileSystem.file(
-    _artifacts!.getHostArtifact(kDartSdkJsArtifactMap[_rendererMode]!));
+    _artifacts!.getHostArtifact(kDartSdkJsArtifactMap[_rendererMode]![_nullSafetyMode]!));
 
   File get _dartSdkSourcemaps => _fileSystem.file(
-    _artifacts!.getHostArtifact(kDartSdkJsMapArtifactMap[_rendererMode]!));
+    _artifacts!.getHostArtifact(kDartSdkJsMapArtifactMap[_rendererMode]![_nullSafetyMode]!));
 
   /// The precompiled test javascript.
   File get _testDartJs => _fileSystem.file(_fileSystem.path.join(
@@ -234,6 +244,7 @@ class FlutterWebPlatform extends PlatformPlugin {
       final String leadingPath = request.url.path.split('.dart.bootstrap.js')[0];
       final String generatedFile = '${_fileSystem.path.split(leadingPath).join('_')}.dart.test.dart.js';
       return shelf.Response.ok(generateMainModule(
+        nullAssertions: nullAssertions!,
         nativeNullAssertions: true,
         bootstrapModule: '${_fileSystem.path.basename(leadingPath)}.dart.bootstrap',
         entrypoint: '/$generatedFile'

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

@@ -161,6 +161,7 @@ class _FlutterTestRunnerImpl implements FlutterTestRunner {
             shellPath: shellPath,
             flutterProject: flutterProject,
             pauseAfterLoad: debuggingOptions.startPaused,
+            nullAssertions: debuggingOptions.nullAssertions,
             buildInfo: debuggingOptions.buildInfo,
             webMemoryFS: result,
             logger: globals.logger,

packages/flutter_tools/lib/src/test/web_test_compiler.dart

@@ -49,9 +49,24 @@ class WebTestCompiler {
     required List<String> testFiles,
     required BuildInfo buildInfo,
   }) async {
+    LanguageVersion languageVersion = LanguageVersion(2, 8);
+    late final String platformDillName;
+
+    // TODO(zanderso): to support autodetect this would need to partition the source code into
+    // a sound and unsound set and perform separate compilations
     final List<String> extraFrontEndOptions = List<String>.of(buildInfo.extraFrontEndOptions);
-    final LanguageVersion languageVersion = currentLanguageVersion(_fileSystem, Cache.flutterRoot!);
+    if (buildInfo.nullSafetyMode == NullSafetyMode.unsound || buildInfo.nullSafetyMode == NullSafetyMode.autodetect) {
-    const String platformDillName = 'ddc_outline_sound.dill';
+      platformDillName = 'ddc_outline.dill';
+      if (!extraFrontEndOptions.contains('--no-sound-null-safety')) {
+        extraFrontEndOptions.add('--no-sound-null-safety');
+      }
+    } else if (buildInfo.nullSafetyMode == NullSafetyMode.sound) {
+      languageVersion = currentLanguageVersion(_fileSystem, Cache.flutterRoot!);
+      platformDillName = 'ddc_outline_sound.dill';
+      if (!extraFrontEndOptions.contains('--sound-null-safety')) {
+        extraFrontEndOptions.add('--sound-null-safety');
+      }
+    }
 
     final String platformDillPath = _fileSystem.path.join(
       getWebPlatformBinariesDirectory(_artifacts, buildInfo.webRenderer).path,

packages/flutter_tools/lib/src/web/bootstrap.dart

@@ -153,6 +153,7 @@ document.head.appendChild(requireEl);
 /// this object is the module.
 String generateMainModule({
   required String entrypoint,
+  required bool nullAssertions,
   required bool nativeNullAssertions,
   String bootstrapModule = 'main_module.bootstrap',
 }) {
@@ -167,6 +168,7 @@ require.config({
 define("$bootstrapModule", ["$entrypoint", "dart_sdk"], function(app, dart_sdk) {
   dart_sdk.dart.setStartAsyncSynchronously(true);
   dart_sdk._debugger.registerDevtoolsFormatter();
+  dart_sdk.dart.nonNullAsserts($nullAssertions);
   dart_sdk.dart.nativeNonNullAsserts($nativeNullAssertions);
 
   // See the generateMainModule doc comment.

packages/flutter_tools/lib/src/web/compile.dart

@@ -119,15 +119,33 @@ enum WebRendererMode {
 }
 
 /// The correct precompiled artifact to use for each build and render mode.
-const Map<WebRendererMode, HostArtifact> kDartSdkJsArtifactMap = <WebRendererMode, HostArtifact>{
+const Map<WebRendererMode, Map<NullSafetyMode, HostArtifact>> kDartSdkJsArtifactMap = <WebRendererMode, Map<NullSafetyMode, HostArtifact>>{
-  WebRendererMode.autoDetect: HostArtifact.webPrecompiledCanvaskitAndHtmlSoundSdk,
+  WebRendererMode.autoDetect: <NullSafetyMode, HostArtifact> {
-  WebRendererMode.canvaskit: HostArtifact.webPrecompiledCanvaskitSoundSdk,
+    NullSafetyMode.sound: HostArtifact.webPrecompiledCanvaskitAndHtmlSoundSdk,
-  WebRendererMode.html: HostArtifact.webPrecompiledSoundSdk,
+    NullSafetyMode.unsound: HostArtifact.webPrecompiledCanvaskitAndHtmlSdk,
+  },
+  WebRendererMode.canvaskit: <NullSafetyMode, HostArtifact> {
+    NullSafetyMode.sound: HostArtifact.webPrecompiledCanvaskitSoundSdk,
+    NullSafetyMode.unsound: HostArtifact.webPrecompiledCanvaskitSdk,
+  },
+  WebRendererMode.html: <NullSafetyMode, HostArtifact> {
+    NullSafetyMode.sound: HostArtifact.webPrecompiledSoundSdk,
+    NullSafetyMode.unsound: HostArtifact.webPrecompiledSdk,
+  },
 };
 
 /// The correct source map artifact to use for each build and render mode.
-const Map<WebRendererMode, HostArtifact> kDartSdkJsMapArtifactMap = <WebRendererMode, HostArtifact>{
+const Map<WebRendererMode, Map<NullSafetyMode, HostArtifact>> kDartSdkJsMapArtifactMap = <WebRendererMode, Map<NullSafetyMode, HostArtifact>>{
-  WebRendererMode.autoDetect: HostArtifact.webPrecompiledCanvaskitAndHtmlSoundSdkSourcemaps,
+  WebRendererMode.autoDetect: <NullSafetyMode, HostArtifact> {
-  WebRendererMode.canvaskit: HostArtifact.webPrecompiledCanvaskitSoundSdkSourcemaps,
+    NullSafetyMode.sound: HostArtifact.webPrecompiledCanvaskitAndHtmlSoundSdkSourcemaps,
-  WebRendererMode.html: HostArtifact.webPrecompiledSoundSdkSourcemaps,
+    NullSafetyMode.unsound: HostArtifact.webPrecompiledCanvaskitAndHtmlSdkSourcemaps,
+  },
+  WebRendererMode.canvaskit: <NullSafetyMode, HostArtifact> {
+    NullSafetyMode.sound: HostArtifact.webPrecompiledCanvaskitSoundSdkSourcemaps,
+    NullSafetyMode.unsound: HostArtifact.webPrecompiledCanvaskitSdkSourcemaps,
+  },
+  WebRendererMode.html: <NullSafetyMode, HostArtifact> {
+    NullSafetyMode.sound: HostArtifact.webPrecompiledSoundSdkSourcemaps,
+    NullSafetyMode.unsound: HostArtifact.webPrecompiledSdkSourcemaps,
+  },
 };

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

@@ -4,6 +4,7 @@
 
 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';
 import 'package:flutter_tools/src/build_system/build_system.dart';
@@ -66,6 +67,7 @@ void main() {
         final FakeFlutterVersion fakeFlutterVersion = FakeFlutterVersion(frameworkVersion: frameworkVersion);
 
         final BuildIOSFrameworkCommand command = BuildIOSFrameworkCommand(
+          logger: BufferLogger.test(),
           buildSystem: TestBuildSystem.all(BuildResult(success: true)),
           platform: fakePlatform,
           flutterVersion: fakeFlutterVersion,
@@ -95,6 +97,7 @@ void main() {
         );
 
         final BuildIOSFrameworkCommand command = BuildIOSFrameworkCommand(
+          logger: BufferLogger.test(),
           buildSystem: TestBuildSystem.all(BuildResult(success: true)),
           platform: fakePlatform,
           flutterVersion: fakeFlutterVersion,
@@ -121,6 +124,7 @@ void main() {
         );
 
         final BuildIOSFrameworkCommand command = BuildIOSFrameworkCommand(
+          logger: BufferLogger.test(),
           buildSystem: TestBuildSystem.all(BuildResult(success: true)),
           platform: fakePlatform,
           flutterVersion: fakeFlutterVersion,
@@ -162,6 +166,7 @@ void main() {
             );
 
             final BuildIOSFrameworkCommand command = BuildIOSFrameworkCommand(
+              logger: BufferLogger.test(),
               buildSystem: TestBuildSystem.all(BuildResult(success: true)),
               platform: fakePlatform,
               flutterVersion: fakeFlutterVersion,
@@ -196,6 +201,7 @@ void main() {
 
           testUsingContext('contains license and version', () async {
             final BuildIOSFrameworkCommand command = BuildIOSFrameworkCommand(
+              logger: BufferLogger.test(),
               buildSystem: TestBuildSystem.all(BuildResult(success: true)),
               platform: fakePlatform,
               flutterVersion: fakeFlutterVersion,
@@ -216,6 +222,7 @@ void main() {
 
           testUsingContext('debug URL', () async {
             final BuildIOSFrameworkCommand command = BuildIOSFrameworkCommand(
+              logger: BufferLogger.test(),
               buildSystem: TestBuildSystem.all(BuildResult(success: true)),
               platform: fakePlatform,
               flutterVersion: fakeFlutterVersion,
@@ -234,6 +241,7 @@ void main() {
 
           testUsingContext('profile URL', () async {
             final BuildIOSFrameworkCommand command = BuildIOSFrameworkCommand(
+              logger: BufferLogger.test(),
               buildSystem: TestBuildSystem.all(BuildResult(success: true)),
               platform: fakePlatform,
               flutterVersion: fakeFlutterVersion,
@@ -252,6 +260,7 @@ void main() {
 
           testUsingContext('release URL', () async {
             final BuildIOSFrameworkCommand command = BuildIOSFrameworkCommand(
+              logger: BufferLogger.test(),
               buildSystem: TestBuildSystem.all(BuildResult(success: true)),
               platform: fakePlatform,
               flutterVersion: fakeFlutterVersion,
@@ -295,6 +304,7 @@ void main() {
         final FakeFlutterVersion fakeFlutterVersion = FakeFlutterVersion(frameworkVersion: frameworkVersion);
 
         final BuildMacOSFrameworkCommand command = BuildMacOSFrameworkCommand(
+          logger: BufferLogger.test(),
           buildSystem: TestBuildSystem.all(BuildResult(success: true)),
           platform: fakePlatform,
           flutterVersion: fakeFlutterVersion,
@@ -324,6 +334,7 @@ void main() {
         );
 
         final BuildMacOSFrameworkCommand command = BuildMacOSFrameworkCommand(
+          logger: BufferLogger.test(),
           buildSystem: TestBuildSystem.all(BuildResult(success: true)),
           platform: fakePlatform,
           flutterVersion: fakeFlutterVersion,
@@ -350,6 +361,7 @@ void main() {
         );
 
         final BuildMacOSFrameworkCommand command = BuildMacOSFrameworkCommand(
+          logger: BufferLogger.test(),
           buildSystem: TestBuildSystem.all(BuildResult(success: true)),
           platform: fakePlatform,
           flutterVersion: fakeFlutterVersion,
@@ -391,6 +403,7 @@ void main() {
             );
 
             final BuildMacOSFrameworkCommand command = BuildMacOSFrameworkCommand(
+              logger: BufferLogger.test(),
               buildSystem: TestBuildSystem.all(BuildResult(success: true)),
               platform: fakePlatform,
               flutterVersion: fakeFlutterVersion,
@@ -425,6 +438,7 @@ void main() {
 
           testUsingContext('contains license and version', () async {
             final BuildMacOSFrameworkCommand command = BuildMacOSFrameworkCommand(
+              logger: BufferLogger.test(),
               buildSystem: TestBuildSystem.all(BuildResult(success: true)),
               platform: fakePlatform,
               flutterVersion: fakeFlutterVersion,
@@ -445,6 +459,7 @@ void main() {
 
           testUsingContext('debug URL', () async {
             final BuildMacOSFrameworkCommand command = BuildMacOSFrameworkCommand(
+              logger: BufferLogger.test(),
               buildSystem: TestBuildSystem.all(BuildResult(success: true)),
               platform: fakePlatform,
               flutterVersion: fakeFlutterVersion,
@@ -463,6 +478,7 @@ void main() {
 
           testUsingContext('profile URL', () async {
             final BuildMacOSFrameworkCommand command = BuildMacOSFrameworkCommand(
+              logger: BufferLogger.test(),
               buildSystem: TestBuildSystem.all(BuildResult(success: true)),
               platform: fakePlatform,
               flutterVersion: fakeFlutterVersion,
@@ -481,6 +497,7 @@ void main() {
 
           testUsingContext('release URL', () async {
             final BuildMacOSFrameworkCommand command = BuildMacOSFrameworkCommand(
+              logger: BufferLogger.test(),
               buildSystem: TestBuildSystem.all(BuildResult(success: true)),
               platform: fakePlatform,
               flutterVersion: fakeFlutterVersion,

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

@@ -6,6 +6,7 @@ import 'package:args/command_runner.dart';
 import 'package:file/memory.dart';
 import 'package:flutter_tools/src/android/android_sdk.dart';
 import 'package:flutter_tools/src/base/file_system.dart';
+import 'package:flutter_tools/src/base/logger.dart';
 import 'package:flutter_tools/src/base/os.dart';
 import 'package:flutter_tools/src/base/platform.dart';
 import 'package:flutter_tools/src/build_info.dart';
@@ -185,6 +186,7 @@ void main() {
       androidSdk: FakeAndroidSdk(),
       buildSystem: TestBuildSystem.all(BuildResult(success: true)),
       fileSystem: MemoryFileSystem.test(),
+      logger: BufferLogger.test(),
       osUtils: FakeOperatingSystemUtils(),
     );
     createCoreMockProjectFiles();
@@ -204,6 +206,7 @@ void main() {
       androidSdk: FakeAndroidSdk(),
       buildSystem: TestBuildSystem.all(BuildResult(success: true)),
       fileSystem: MemoryFileSystem.test(),
+      logger: BufferLogger.test(),
       osUtils: FakeOperatingSystemUtils(),
     );
     createCoreMockProjectFiles();
@@ -223,6 +226,7 @@ void main() {
       androidSdk: FakeAndroidSdk(),
       buildSystem: TestBuildSystem.all(BuildResult(success: true)),
       fileSystem: MemoryFileSystem.test(),
+      logger: BufferLogger.test(),
       osUtils: FakeOperatingSystemUtils(),
     );
     fileSystem.file('pubspec.yaml').createSync();
@@ -230,7 +234,7 @@ void main() {
     fileSystem.file(fileSystem.path.join('lib', 'main.dart'))
       .createSync(recursive: true);
 
-    final bool supported = BuildIOSCommand(verboseHelp: false).supported;
+    final bool supported = BuildIOSCommand(logger: BufferLogger.test(), verboseHelp: false).supported;
     expect(createTestCommandRunner(command).run(
       const <String>['build', 'ios', '--no-pub']
     ), supported ? throwsToolExit() : throwsA(isA<UsageException>()));
@@ -246,6 +250,7 @@ void main() {
       androidSdk: FakeAndroidSdk(),
       buildSystem: TestBuildSystem.all(BuildResult(success: true)),
       fileSystem: MemoryFileSystem.test(),
+      logger: BufferLogger.test(),
       osUtils: FakeOperatingSystemUtils(),
     );
     createMinimalMockProjectFiles();
@@ -272,6 +277,7 @@ void main() {
       androidSdk: FakeAndroidSdk(),
       buildSystem: TestBuildSystem.all(BuildResult(success: true)),
       fileSystem: MemoryFileSystem.test(),
+      logger: BufferLogger.test(),
       osUtils: FakeOperatingSystemUtils(),
     );
     createMinimalMockProjectFiles();
@@ -298,6 +304,7 @@ void main() {
       androidSdk: FakeAndroidSdk(),
       buildSystem: TestBuildSystem.all(BuildResult(success: true)),
       fileSystem: MemoryFileSystem.test(),
+      logger: BufferLogger.test(),
       osUtils: FakeOperatingSystemUtils(),
     );
     createMinimalMockProjectFiles();
@@ -323,6 +330,7 @@ void main() {
       androidSdk: FakeAndroidSdk(),
       buildSystem: TestBuildSystem.all(BuildResult(success: true)),
       fileSystem: MemoryFileSystem.test(),
+      logger: BufferLogger.test(),
       osUtils: FakeOperatingSystemUtils(),
     );
     createMinimalMockProjectFiles();
@@ -348,6 +356,7 @@ void main() {
       androidSdk: FakeAndroidSdk(),
       buildSystem: TestBuildSystem.all(BuildResult(success: true)),
       fileSystem: MemoryFileSystem.test(),
+      logger: BufferLogger.test(),
       osUtils: FakeOperatingSystemUtils(),
     );
     createMinimalMockProjectFiles();
@@ -397,6 +406,7 @@ void main() {
         androidSdk: FakeAndroidSdk(),
         buildSystem: TestBuildSystem.all(BuildResult(success: true)),
         fileSystem: MemoryFileSystem.test(),
+        logger: BufferLogger.test(),
         osUtils: FakeOperatingSystemUtils(),
       );
 
@@ -427,6 +437,7 @@ void main() {
         androidSdk: FakeAndroidSdk(),
         buildSystem: TestBuildSystem.all(BuildResult(success: true)),
         fileSystem: MemoryFileSystem.test(),
+        logger: BufferLogger.test(),
         osUtils: FakeOperatingSystemUtils(),
       );
 
@@ -461,6 +472,7 @@ void main() {
         androidSdk: FakeAndroidSdk(),
         buildSystem: TestBuildSystem.all(BuildResult(success: true)),
         fileSystem: MemoryFileSystem.test(),
+        logger: BufferLogger.test(),
         osUtils: FakeOperatingSystemUtils(),
       );
 
@@ -494,6 +506,7 @@ void main() {
         androidSdk: FakeAndroidSdk(),
         buildSystem: TestBuildSystem.all(BuildResult(success: true)),
         fileSystem: MemoryFileSystem.test(),
+        logger: BufferLogger.test(),
         osUtils: FakeOperatingSystemUtils(),
       );
 
@@ -522,6 +535,7 @@ void main() {
         androidSdk: FakeAndroidSdk(),
         buildSystem: TestBuildSystem.all(BuildResult(success: true)),
         fileSystem: MemoryFileSystem.test(),
+        logger: BufferLogger.test(),
         osUtils: FakeOperatingSystemUtils(),
       );
 
@@ -556,6 +570,7 @@ void main() {
         androidSdk: FakeAndroidSdk(),
         buildSystem: TestBuildSystem.all(BuildResult(success: true)),
         fileSystem: MemoryFileSystem.test(),
+        logger: BufferLogger.test(),
         osUtils: FakeOperatingSystemUtils(),
       );
 
@@ -590,6 +605,7 @@ void main() {
         androidSdk: FakeAndroidSdk(),
         buildSystem: TestBuildSystem.all(BuildResult(success: true)),
         fileSystem: MemoryFileSystem.test(),
+        logger: BufferLogger.test(),
         osUtils: FakeOperatingSystemUtils(),
       );
 
@@ -626,6 +642,7 @@ Runner requires a provisioning profile. Select a provisioning profile in the Sig
         androidSdk: FakeAndroidSdk(),
         buildSystem: TestBuildSystem.all(BuildResult(success: true)),
         fileSystem: MemoryFileSystem.test(),
+        logger: BufferLogger.test(),
         osUtils: FakeOperatingSystemUtils(),
       );
 
@@ -659,6 +676,7 @@ Runner requires a provisioning profile. Select a provisioning profile in the Sig
         androidSdk: FakeAndroidSdk(),
         buildSystem: TestBuildSystem.all(BuildResult(success: true)),
         fileSystem: MemoryFileSystem.test(),
+        logger: BufferLogger.test(),
         osUtils: FakeOperatingSystemUtils(),
       );
 
@@ -696,6 +714,7 @@ Runner requires a provisioning profile. Select a provisioning profile in the Sig
         androidSdk: FakeAndroidSdk(),
         buildSystem: TestBuildSystem.all(BuildResult(success: true)),
         fileSystem: MemoryFileSystem.test(),
+        logger: BufferLogger.test(),
         osUtils: FakeOperatingSystemUtils(),
       );
 
@@ -729,6 +748,7 @@ Runner requires a provisioning profile. Select a provisioning profile in the Sig
         androidSdk: FakeAndroidSdk(),
         buildSystem: TestBuildSystem.all(BuildResult(success: true)),
         fileSystem: MemoryFileSystem.test(),
+        logger: BufferLogger.test(),
         osUtils: FakeOperatingSystemUtils(),
       );
 
@@ -763,6 +783,7 @@ Runner requires a provisioning profile. Select a provisioning profile in the Sig
         androidSdk: FakeAndroidSdk(),
         buildSystem: TestBuildSystem.all(BuildResult(success: true)),
         fileSystem: MemoryFileSystem.test(),
+        logger: BufferLogger.test(),
         osUtils: FakeOperatingSystemUtils(),
       );
 
@@ -799,6 +820,7 @@ Runner requires a provisioning profile. Select a provisioning profile in the Sig
         androidSdk: FakeAndroidSdk(),
         buildSystem: TestBuildSystem.all(BuildResult(success: true)),
         fileSystem: MemoryFileSystem.test(),
+        logger: BufferLogger.test(),
         osUtils: FakeOperatingSystemUtils(),
       );
 
@@ -833,6 +855,7 @@ Runner requires a provisioning profile. Select a provisioning profile in the Sig
         androidSdk: FakeAndroidSdk(),
         buildSystem: TestBuildSystem.all(BuildResult(success: true)),
         fileSystem: MemoryFileSystem.test(),
+        logger: BufferLogger.test(),
         osUtils: FakeOperatingSystemUtils(),
       );
 
@@ -868,6 +891,7 @@ Runner requires a provisioning profile. Select a provisioning profile in the Sig
         androidSdk: FakeAndroidSdk(),
         buildSystem: TestBuildSystem.all(BuildResult(success: true)),
         fileSystem: MemoryFileSystem.test(),
+        logger: BufferLogger.test(),
         osUtils: FakeOperatingSystemUtils(),
       );
 
@@ -905,6 +929,7 @@ Runner requires a provisioning profile. Select a provisioning profile in the Sig
         androidSdk: FakeAndroidSdk(),
         buildSystem: TestBuildSystem.all(BuildResult(success: true)),
         fileSystem: MemoryFileSystem.test(),
+        logger: BufferLogger.test(),
         osUtils: FakeOperatingSystemUtils(),
       );
 

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

@@ -7,6 +7,7 @@ import 'dart:typed_data';
 import 'package:args/command_runner.dart';
 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_system/build_system.dart';
 import 'package:flutter_tools/src/cache.dart';
@@ -197,6 +198,7 @@ void main() {
       androidSdk: FakeAndroidSdk(),
       buildSystem: TestBuildSystem.all(BuildResult(success: true)),
       fileSystem: MemoryFileSystem.test(),
+      logger: BufferLogger.test(),
       osUtils: FakeOperatingSystemUtils(),
     );
     createCoreMockProjectFiles();
@@ -216,6 +218,7 @@ void main() {
       androidSdk: FakeAndroidSdk(),
       buildSystem: TestBuildSystem.all(BuildResult(success: true)),
       fileSystem: MemoryFileSystem.test(),
+      logger: BufferLogger.test(),
       osUtils: FakeOperatingSystemUtils(),
     );
     createCoreMockProjectFiles();
@@ -235,6 +238,7 @@ void main() {
       androidSdk: FakeAndroidSdk(),
       buildSystem: TestBuildSystem.all(BuildResult(success: true)),
       fileSystem: MemoryFileSystem.test(),
+      logger: BufferLogger.test(),
       osUtils: FakeOperatingSystemUtils(),
     );
     fileSystem.file('pubspec.yaml').createSync();
@@ -242,7 +246,7 @@ void main() {
     fileSystem.file(fileSystem.path.join('lib', 'main.dart'))
       .createSync(recursive: true);
 
-    final bool supported = BuildIOSArchiveCommand(verboseHelp: false).supported;
+    final bool supported = BuildIOSArchiveCommand(logger: BufferLogger.test(), verboseHelp: false).supported;
     expect(createTestCommandRunner(command).run(
       const <String>['build', 'ipa', '--no-pub']
     ), supported ? throwsToolExit() : throwsA(isA<UsageException>()));
@@ -259,6 +263,7 @@ void main() {
       androidSdk: FakeAndroidSdk(),
       buildSystem: TestBuildSystem.all(BuildResult(success: true)),
       fileSystem: MemoryFileSystem.test(),
+      logger: BufferLogger.test(),
       osUtils: FakeOperatingSystemUtils(),
     );
     createMinimalMockProjectFiles();
@@ -287,6 +292,7 @@ void main() {
       androidSdk: FakeAndroidSdk(),
       buildSystem: TestBuildSystem.all(BuildResult(success: true)),
       fileSystem: MemoryFileSystem.test(),
+      logger: BufferLogger.test(),
       osUtils: FakeOperatingSystemUtils(),
     );
     createMinimalMockProjectFiles();
@@ -313,6 +319,7 @@ void main() {
       androidSdk: FakeAndroidSdk(),
       buildSystem: TestBuildSystem.all(BuildResult(success: true)),
       fileSystem: MemoryFileSystem.test(),
+      logger: BufferLogger.test(),
       osUtils: FakeOperatingSystemUtils(),
     );
     createMinimalMockProjectFiles();
@@ -341,6 +348,7 @@ void main() {
       androidSdk: FakeAndroidSdk(),
       buildSystem: TestBuildSystem.all(BuildResult(success: true)),
       fileSystem: MemoryFileSystem.test(),
+      logger: BufferLogger.test(),
       osUtils: FakeOperatingSystemUtils(),
     );
     fakeProcessManager.addCommands(<FakeCommand>[
@@ -388,6 +396,7 @@ void main() {
       androidSdk: FakeAndroidSdk(),
       buildSystem: TestBuildSystem.all(BuildResult(success: true)),
       fileSystem: MemoryFileSystem.test(),
+      logger: BufferLogger.test(),
       osUtils: FakeOperatingSystemUtils(),
     );
     fakeProcessManager.addCommands(<FakeCommand>[
@@ -436,6 +445,7 @@ void main() {
       androidSdk: FakeAndroidSdk(),
       buildSystem: TestBuildSystem.all(BuildResult(success: true)),
       fileSystem: MemoryFileSystem.test(),
+      logger: BufferLogger.test(),
       osUtils: FakeOperatingSystemUtils(),
     );
     fakeProcessManager.addCommands(<FakeCommand>[
@@ -484,6 +494,7 @@ void main() {
       androidSdk: FakeAndroidSdk(),
       buildSystem: TestBuildSystem.all(BuildResult(success: true)),
       fileSystem: MemoryFileSystem.test(),
+      logger: BufferLogger.test(),
       osUtils: FakeOperatingSystemUtils(),
     );
     fakeProcessManager.addCommands(<FakeCommand>[
@@ -531,6 +542,7 @@ void main() {
       androidSdk: FakeAndroidSdk(),
       buildSystem: TestBuildSystem.all(BuildResult(success: true)),
       fileSystem: MemoryFileSystem.test(),
+      logger: BufferLogger.test(),
       osUtils: FakeOperatingSystemUtils(),
     );
     fakeProcessManager.addCommands(<FakeCommand>[
@@ -556,6 +568,7 @@ void main() {
       androidSdk: FakeAndroidSdk(),
       buildSystem: TestBuildSystem.all(BuildResult(success: true)),
       fileSystem: MemoryFileSystem.test(),
+      logger: BufferLogger.test(),
       osUtils: FakeOperatingSystemUtils(),
     );
     fakeProcessManager.addCommands(<FakeCommand>[
@@ -604,6 +617,7 @@ void main() {
       androidSdk: FakeAndroidSdk(),
       buildSystem: TestBuildSystem.all(BuildResult(success: true)),
       fileSystem: MemoryFileSystem.test(),
+      logger: BufferLogger.test(),
       osUtils: FakeOperatingSystemUtils(),
     );
     createMinimalMockProjectFiles();
@@ -626,6 +640,7 @@ void main() {
       androidSdk: FakeAndroidSdk(),
       buildSystem: TestBuildSystem.all(BuildResult(success: true)),
       fileSystem: MemoryFileSystem.test(),
+      logger: BufferLogger.test(),
       osUtils: FakeOperatingSystemUtils(),
     );
     createMinimalMockProjectFiles();
@@ -682,6 +697,7 @@ void main() {
       androidSdk: FakeAndroidSdk(),
       buildSystem: TestBuildSystem.all(BuildResult(success: true)),
       fileSystem: MemoryFileSystem.test(),
+      logger: BufferLogger.test(),
       osUtils: FakeOperatingSystemUtils(),
     );
     fakeProcessManager.addCommands(<FakeCommand>[
@@ -715,6 +731,7 @@ void main() {
       androidSdk: FakeAndroidSdk(),
       buildSystem: TestBuildSystem.all(BuildResult(success: true)),
       fileSystem: MemoryFileSystem.test(),
+      logger: BufferLogger.test(),
       osUtils: FakeOperatingSystemUtils(),
     );
     fakeProcessManager.addCommands(<FakeCommand>[
@@ -745,6 +762,7 @@ void main() {
       androidSdk: FakeAndroidSdk(),
       buildSystem: TestBuildSystem.all(BuildResult(success: true)),
       fileSystem: MemoryFileSystem.test(),
+      logger: BufferLogger.test(),
       osUtils: FakeOperatingSystemUtils(),
     );
     fakeProcessManager.addCommands(<FakeCommand>[
@@ -776,6 +794,7 @@ void main() {
       androidSdk: FakeAndroidSdk(),
       buildSystem: TestBuildSystem.all(BuildResult(success: true)),
       fileSystem: MemoryFileSystem.test(),
+      logger: BufferLogger.test(),
       osUtils: FakeOperatingSystemUtils(),
     );
     fakeProcessManager.addCommands(<FakeCommand>[
@@ -809,6 +828,7 @@ void main() {
       androidSdk: FakeAndroidSdk(),
       buildSystem: TestBuildSystem.all(BuildResult(success: true)),
       fileSystem: MemoryFileSystem.test(),
+      logger: BufferLogger.test(),
       osUtils: FakeOperatingSystemUtils(),
     );
     fakeProcessManager.addCommands(<FakeCommand>[
@@ -837,6 +857,7 @@ void main() {
       androidSdk: FakeAndroidSdk(),
       buildSystem: TestBuildSystem.all(BuildResult(success: true)),
       fileSystem: MemoryFileSystem.test(),
+      logger: BufferLogger.test(),
       osUtils: FakeOperatingSystemUtils(),
     );
     fakeProcessManager.addCommands(<FakeCommand>[
@@ -888,6 +909,7 @@ void main() {
       androidSdk: FakeAndroidSdk(),
       buildSystem: TestBuildSystem.all(BuildResult(success: true)),
       fileSystem: MemoryFileSystem.test(),
+      logger: BufferLogger.test(),
       osUtils: FakeOperatingSystemUtils(),
     );
     await createTestCommandRunner(command).run(
@@ -941,6 +963,7 @@ void main() {
       androidSdk: FakeAndroidSdk(),
       buildSystem: TestBuildSystem.all(BuildResult(success: true)),
       fileSystem: MemoryFileSystem.test(),
+      logger: BufferLogger.test(),
       osUtils: FakeOperatingSystemUtils(),
     );
     await createTestCommandRunner(command).run(
@@ -990,6 +1013,7 @@ void main() {
       androidSdk: FakeAndroidSdk(),
       buildSystem: TestBuildSystem.all(BuildResult(success: true)),
       fileSystem: MemoryFileSystem.test(),
+      logger: BufferLogger.test(),
       osUtils: FakeOperatingSystemUtils(),
     );
     await createTestCommandRunner(command).run(
@@ -1028,6 +1052,7 @@ void main() {
       androidSdk: FakeAndroidSdk(),
       buildSystem: TestBuildSystem.all(BuildResult(success: true)),
       fileSystem: MemoryFileSystem.test(),
+      logger: BufferLogger.test(),
       osUtils: FakeOperatingSystemUtils(),
     );
     await createTestCommandRunner(command).run(
@@ -1108,6 +1133,7 @@ void main() {
       androidSdk: FakeAndroidSdk(),
       buildSystem: TestBuildSystem.all(BuildResult(success: true)),
       fileSystem: MemoryFileSystem.test(),
+      logger: BufferLogger.test(),
       osUtils: FakeOperatingSystemUtils(),
     );
     await createTestCommandRunner(command).run(
@@ -1186,6 +1212,7 @@ void main() {
       androidSdk: FakeAndroidSdk(),
       buildSystem: TestBuildSystem.all(BuildResult(success: true)),
       fileSystem: MemoryFileSystem.test(),
+      logger: BufferLogger.test(),
       osUtils: FakeOperatingSystemUtils(),
     );
     await createTestCommandRunner(command).run(
@@ -1244,6 +1271,7 @@ void main() {
       androidSdk: FakeAndroidSdk(),
       buildSystem: TestBuildSystem.all(BuildResult(success: true)),
       fileSystem: MemoryFileSystem.test(),
+      logger: BufferLogger.test(),
       osUtils: FakeOperatingSystemUtils(),
     );
     await createTestCommandRunner(command).run(
@@ -1302,6 +1330,7 @@ void main() {
       androidSdk: FakeAndroidSdk(),
       buildSystem: TestBuildSystem.all(BuildResult(success: true)),
       fileSystem: MemoryFileSystem.test(),
+      logger: BufferLogger.test(),
       osUtils: FakeOperatingSystemUtils(),
     );
     await createTestCommandRunner(command).run(
@@ -1360,6 +1389,7 @@ void main() {
       androidSdk: FakeAndroidSdk(),
       buildSystem: TestBuildSystem.all(BuildResult(success: true)),
       fileSystem: MemoryFileSystem.test(),
+      logger: BufferLogger.test(),
       osUtils: FakeOperatingSystemUtils(),
     );
     await createTestCommandRunner(command).run(
@@ -1419,6 +1449,7 @@ void main() {
       androidSdk: FakeAndroidSdk(),
       buildSystem: TestBuildSystem.all(BuildResult(success: true)),
       fileSystem: MemoryFileSystem.test(),
+      logger: BufferLogger.test(),
       osUtils: FakeOperatingSystemUtils(),
     );
     await createTestCommandRunner(command).run(
@@ -1522,6 +1553,7 @@ void main() {
       androidSdk: FakeAndroidSdk(),
       buildSystem: TestBuildSystem.all(BuildResult(success: true)),
       fileSystem: MemoryFileSystem.test(),
+      logger: BufferLogger.test(),
       osUtils: FakeOperatingSystemUtils(),
     );
     await createTestCommandRunner(command).run(
@@ -1601,6 +1633,7 @@ void main() {
       androidSdk: FakeAndroidSdk(),
       buildSystem: TestBuildSystem.all(BuildResult(success: true)),
       fileSystem: MemoryFileSystem.test(),
+      logger: BufferLogger.test(),
       osUtils: FakeOperatingSystemUtils(),
     );
     await createTestCommandRunner(command).run(
@@ -1678,6 +1711,7 @@ void main() {
       androidSdk: FakeAndroidSdk(),
       buildSystem: TestBuildSystem.all(BuildResult(success: true)),
       fileSystem: MemoryFileSystem.test(),
+      logger: BufferLogger.test(),
       osUtils: FakeOperatingSystemUtils(),
     );
     await createTestCommandRunner(command).run(

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

@@ -6,6 +6,7 @@ import 'package:args/command_runner.dart';
 import 'package:file/memory.dart';
 import 'package:file_testing/file_testing.dart';
 import 'package:flutter_tools/src/base/file_system.dart';
+import 'package:flutter_tools/src/base/logger.dart';
 import 'package:flutter_tools/src/base/os.dart';
 import 'package:flutter_tools/src/base/platform.dart';
 import 'package:flutter_tools/src/base/utils.dart';
@@ -112,6 +113,7 @@ void main() {
       androidSdk: FakeAndroidSdk(),
       buildSystem: TestBuildSystem.all(BuildResult(success: true)),
       fileSystem: MemoryFileSystem.test(),
+      logger: BufferLogger.test(),
       osUtils: FakeOperatingSystemUtils(),
     );
     setUpMockCoreProjectFiles();
@@ -133,6 +135,7 @@ void main() {
       androidSdk: FakeAndroidSdk(),
       buildSystem: TestBuildSystem.all(BuildResult(success: true)),
       fileSystem: MemoryFileSystem.test(),
+      logger: BufferLogger.test(),
       osUtils: FakeOperatingSystemUtils(),
     );
     setUpMockProjectFilesForBuild();
@@ -152,6 +155,7 @@ void main() {
       androidSdk: FakeAndroidSdk(),
       buildSystem: TestBuildSystem.all(BuildResult(success: true)),
       fileSystem: MemoryFileSystem.test(),
+      logger: BufferLogger.test(),
       osUtils: FakeOperatingSystemUtils(),
     );
     setUpMockProjectFilesForBuild();
@@ -171,6 +175,7 @@ void main() {
       androidSdk: FakeAndroidSdk(),
       buildSystem: TestBuildSystem.all(BuildResult(success: true)),
       fileSystem: MemoryFileSystem.test(),
+      logger: BufferLogger.test(),
       osUtils: FakeOperatingSystemUtils(),
     );
     processManager = FakeProcessManager.list(<FakeCommand>[
@@ -197,6 +202,7 @@ void main() {
       androidSdk: FakeAndroidSdk(),
       buildSystem: TestBuildSystem.all(BuildResult(success: true)),
       fileSystem: MemoryFileSystem.test(),
+      logger: BufferLogger.test(),
       osUtils: FakeOperatingSystemUtils(),
     );
     setUpMockProjectFilesForBuild();
@@ -219,6 +225,7 @@ void main() {
       androidSdk: FakeAndroidSdk(),
       buildSystem: TestBuildSystem.all(BuildResult(success: true)),
       fileSystem: MemoryFileSystem.test(),
+      logger: BufferLogger.test(),
       osUtils: FakeOperatingSystemUtils(),
     );
     setUpMockProjectFilesForBuild();
@@ -245,6 +252,7 @@ void main() {
       androidSdk: FakeAndroidSdk(),
       buildSystem: TestBuildSystem.all(BuildResult(success: true)),
       fileSystem: MemoryFileSystem.test(),
+      logger: BufferLogger.test(),
       osUtils: FakeOperatingSystemUtils(),
     );
     setUpMockProjectFilesForBuild();
@@ -275,6 +283,7 @@ void main() {
       androidSdk: FakeAndroidSdk(),
       buildSystem: TestBuildSystem.all(BuildResult(success: true)),
       fileSystem: MemoryFileSystem.test(),
+      logger: BufferLogger.test(),
       osUtils: FakeOperatingSystemUtils(),
     );
     setUpMockProjectFilesForBuild();
@@ -334,6 +343,7 @@ ERROR: No file or variants found for asset: images/a_dot_burr.jpeg
       androidSdk: FakeAndroidSdk(),
       buildSystem: TestBuildSystem.all(BuildResult(success: true)),
       fileSystem: MemoryFileSystem.test(),
+      logger: BufferLogger.test(),
       osUtils: FakeOperatingSystemUtils(),
     );
     setUpMockProjectFilesForBuild();
@@ -367,6 +377,7 @@ ERROR: No file or variants found for asset: images/a_dot_burr.jpeg
       androidSdk: FakeAndroidSdk(),
       buildSystem: TestBuildSystem.all(BuildResult(success: true)),
       fileSystem: MemoryFileSystem.test(),
+      logger: BufferLogger.test(),
       osUtils: FakeOperatingSystemUtils(),
     );
     setUpMockProjectFilesForBuild();
@@ -391,6 +402,7 @@ ERROR: No file or variants found for asset: images/a_dot_burr.jpeg
       androidSdk: FakeAndroidSdk(),
       buildSystem: TestBuildSystem.all(BuildResult(success: true)),
       fileSystem: MemoryFileSystem.test(),
+      logger: BufferLogger.test(),
       osUtils: CustomFakeOperatingSystemUtils(hostPlatform: HostPlatform.linux_arm64),
     );
     setUpMockProjectFilesForBuild();
@@ -414,6 +426,7 @@ ERROR: No file or variants found for asset: images/a_dot_burr.jpeg
       androidSdk: FakeAndroidSdk(),
       buildSystem: TestBuildSystem.all(BuildResult(success: true)),
       fileSystem: MemoryFileSystem.test(),
+      logger: BufferLogger.test(),
       osUtils: FakeOperatingSystemUtils(),
     );
     setUpMockProjectFilesForBuild();
@@ -438,6 +451,7 @@ ERROR: No file or variants found for asset: images/a_dot_burr.jpeg
       androidSdk: FakeAndroidSdk(),
       buildSystem: TestBuildSystem.all(BuildResult(success: true)),
       fileSystem: MemoryFileSystem.test(),
+      logger: BufferLogger.test(),
       osUtils: CustomFakeOperatingSystemUtils(hostPlatform: HostPlatform.linux_arm64),
     );
     setUpMockProjectFilesForBuild();
@@ -461,6 +475,7 @@ ERROR: No file or variants found for asset: images/a_dot_burr.jpeg
       androidSdk: FakeAndroidSdk(),
       buildSystem: TestBuildSystem.all(BuildResult(success: true)),
       fileSystem: MemoryFileSystem.test(),
+      logger: BufferLogger.test(),
       osUtils: CustomFakeOperatingSystemUtils(hostPlatform: HostPlatform.linux_arm64),
     );
 
@@ -477,6 +492,7 @@ ERROR: No file or variants found for asset: images/a_dot_burr.jpeg
       androidSdk: FakeAndroidSdk(),
       buildSystem: TestBuildSystem.all(BuildResult(success: true)),
       fileSystem: MemoryFileSystem.test(),
+      logger: BufferLogger.test(),
       osUtils: FakeOperatingSystemUtils(),
     );
     setUpMockProjectFilesForBuild();
@@ -569,6 +585,7 @@ set(BINARY_NAME "fizz_bar")
       androidSdk: FakeAndroidSdk(),
       buildSystem: TestBuildSystem.all(BuildResult(success: true)),
       fileSystem: MemoryFileSystem.test(),
+      logger: BufferLogger.test(),
       osUtils: FakeOperatingSystemUtils(),
     ));
 
@@ -579,14 +596,14 @@ set(BINARY_NAME "fizz_bar")
   });
 
   testUsingContext('hidden when not enabled on Linux host', () {
-    expect(BuildLinuxCommand(operatingSystemUtils: FakeOperatingSystemUtils()).hidden, true);
+    expect(BuildLinuxCommand(logger: BufferLogger.test(), operatingSystemUtils: FakeOperatingSystemUtils()).hidden, true);
   }, overrides: <Type, Generator>{
     FeatureFlags: () => TestFeatureFlags(),
     Platform: () => notLinuxPlatform,
   });
 
   testUsingContext('Not hidden when enabled and on Linux host', () {
-    expect(BuildLinuxCommand(operatingSystemUtils: FakeOperatingSystemUtils()).hidden, false);
+    expect(BuildLinuxCommand(logger: BufferLogger.test(), operatingSystemUtils: FakeOperatingSystemUtils()).hidden, false);
   }, overrides: <Type, Generator>{
     FeatureFlags: () => TestFeatureFlags(isLinuxEnabled: true),
     Platform: () => linuxPlatform,
@@ -597,6 +614,7 @@ set(BINARY_NAME "fizz_bar")
       androidSdk: FakeAndroidSdk(),
       buildSystem: TestBuildSystem.all(BuildResult(success: true)),
       fileSystem: MemoryFileSystem.test(),
+      logger: BufferLogger.test(),
       osUtils: FakeOperatingSystemUtils(),
     );
     setUpMockProjectFilesForBuild();
@@ -647,6 +665,7 @@ set(BINARY_NAME "fizz_bar")
       androidSdk: FakeAndroidSdk(),
       buildSystem: TestBuildSystem.all(BuildResult(success: true)),
       fileSystem: MemoryFileSystem.test(),
+      logger: BufferLogger.test(),
       osUtils: CustomFakeOperatingSystemUtils(hostPlatform: HostPlatform.linux_arm64),
     );
     setUpMockProjectFilesForBuild();

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

@@ -142,6 +142,7 @@ STDERR STUFF
       androidSdk: FakeAndroidSdk(),
       buildSystem: TestBuildSystem.all(BuildResult(success: true)),
       fileSystem: MemoryFileSystem.test(),
+      logger: BufferLogger.test(),
       osUtils: FakeOperatingSystemUtils(),
     );
     createCoreMockProjectFiles();
@@ -163,6 +164,7 @@ STDERR STUFF
       androidSdk: FakeAndroidSdk(),
       buildSystem: TestBuildSystem.all(BuildResult(success: true)),
       fileSystem: MemoryFileSystem.test(),
+      logger: BufferLogger.test(),
       osUtils: FakeOperatingSystemUtils(),
     );
     fileSystem.file('pubspec.yaml').createSync();
@@ -184,6 +186,7 @@ STDERR STUFF
       androidSdk: FakeAndroidSdk(),
       buildSystem: TestBuildSystem.all(BuildResult(success: true)),
       fileSystem: MemoryFileSystem.test(),
+      logger: BufferLogger.test(),
       osUtils: FakeOperatingSystemUtils(),
     );
     fileSystem.file('pubspec.yaml').createSync();
@@ -205,6 +208,7 @@ STDERR STUFF
       androidSdk: FakeAndroidSdk(),
       buildSystem: TestBuildSystem.all(BuildResult(success: true)),
       fileSystem: MemoryFileSystem.test(),
+      logger: BufferLogger.test(),
       osUtils: FakeOperatingSystemUtils(),
     );
     createMinimalMockProjectFiles();
@@ -234,6 +238,7 @@ STDERR STUFF
       androidSdk: FakeAndroidSdk(),
       buildSystem: TestBuildSystem.all(BuildResult(success: true)),
       fileSystem: MemoryFileSystem.test(),
+      logger: BufferLogger.test(),
       osUtils: FakeOperatingSystemUtils(),
     );
     createMinimalMockProjectFiles();
@@ -255,6 +260,7 @@ STDERR STUFF
       androidSdk: FakeAndroidSdk(),
       buildSystem: TestBuildSystem.all(BuildResult(success: true)),
       fileSystem: MemoryFileSystem.test(),
+      logger: BufferLogger.test(),
       osUtils: FakeOperatingSystemUtils(),
     );
     createMinimalMockProjectFiles();
@@ -277,6 +283,7 @@ STDERR STUFF
       androidSdk: FakeAndroidSdk(),
       buildSystem: TestBuildSystem.all(BuildResult(success: true)),
       fileSystem: MemoryFileSystem.test(),
+      logger: BufferLogger.test(),
       osUtils: FakeOperatingSystemUtils(),
     );
     createMinimalMockProjectFiles();
@@ -299,6 +306,7 @@ STDERR STUFF
       androidSdk: FakeAndroidSdk(),
       buildSystem: TestBuildSystem.all(BuildResult(success: true)),
       fileSystem: MemoryFileSystem.test(),
+      logger: BufferLogger.test(),
       osUtils: FakeOperatingSystemUtils(),
     );
     createMinimalMockProjectFiles();
@@ -320,6 +328,7 @@ STDERR STUFF
       androidSdk: FakeAndroidSdk(),
       buildSystem: TestBuildSystem.all(BuildResult(success: true)),
       fileSystem: MemoryFileSystem.test(),
+      logger: BufferLogger.test(),
       osUtils: FakeOperatingSystemUtils(),
     );
     createMinimalMockProjectFiles();
@@ -410,6 +419,7 @@ STDERR STUFF
       androidSdk: FakeAndroidSdk(),
       buildSystem: TestBuildSystem.all(BuildResult(success: true)),
       fileSystem: fileSystem,
+      logger: BufferLogger.test(),
       osUtils: FakeOperatingSystemUtils(),
     );
 
@@ -431,6 +441,7 @@ STDERR STUFF
       androidSdk: FakeAndroidSdk(),
       buildSystem: TestBuildSystem.all(BuildResult(success: true)),
       fileSystem: MemoryFileSystem.test(),
+      logger: BufferLogger.test(),
       osUtils: FakeOperatingSystemUtils(),
     );
     createMinimalMockProjectFiles();
@@ -465,10 +476,11 @@ STDERR STUFF
       androidSdk: FakeAndroidSdk(),
       buildSystem: TestBuildSystem.all(BuildResult(success: true)),
       fileSystem: MemoryFileSystem.test(),
+      logger: BufferLogger.test(),
       osUtils: FakeOperatingSystemUtils(),
     ));
 
-    final bool supported = BuildMacosCommand(verboseHelp: false).supported;
+    final bool supported = BuildMacosCommand(logger: BufferLogger.test(), verboseHelp: false).supported;
     expect(() => runner.run(<String>['build', 'macos', '--no-pub']),
       supported ? throwsToolExit() : throwsA(isA<UsageException>()));
   }, overrides: <Type, Generator>{
@@ -476,14 +488,14 @@ STDERR STUFF
   });
 
   testUsingContext('hidden when not enabled on macOS host', () {
-    expect(BuildMacosCommand(verboseHelp: false).hidden, true);
+    expect(BuildMacosCommand(logger: BufferLogger.test(), verboseHelp: false).hidden, true);
   }, overrides: <Type, Generator>{
     FeatureFlags: () => TestFeatureFlags(),
     Platform: () => macosPlatform,
   });
 
   testUsingContext('Not hidden when enabled and on macOS host', () {
-    expect(BuildMacosCommand(verboseHelp: false).hidden, false);
+    expect(BuildMacosCommand(logger: BufferLogger.test(), verboseHelp: false).hidden, false);
   }, overrides: <Type, Generator>{
     FeatureFlags: () => TestFeatureFlags(isMacOSEnabled: true),
     Platform: () => macosPlatform,
@@ -494,6 +506,7 @@ STDERR STUFF
       androidSdk: FakeAndroidSdk(),
       buildSystem: TestBuildSystem.all(BuildResult(success: true)),
       fileSystem: MemoryFileSystem.test(),
+      logger: BufferLogger.test(),
       osUtils: FakeOperatingSystemUtils(),
     );
     createMinimalMockProjectFiles();

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

@@ -5,6 +5,7 @@
 import 'package:args/command_runner.dart';
 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/build_system/build_system.dart';
 import 'package:flutter_tools/src/cache.dart';
 import 'package:flutter_tools/src/commands/build.dart';
@@ -43,6 +44,7 @@ void main() {
         androidSdk: FakeAndroidSdk(),
         buildSystem: TestBuildSystem.all(BuildResult(success: true)),
         fileSystem: MemoryFileSystem.test(),
+        logger: BufferLogger.test(),
         osUtils: FakeOperatingSystemUtils(),
       );
       try {
@@ -64,6 +66,7 @@ void main() {
         androidSdk: FakeAndroidSdk(),
         buildSystem: TestBuildSystem.all(BuildResult(success: true)),
         fileSystem: MemoryFileSystem.test(),
+        logger: BufferLogger.test(),
         osUtils: FakeOperatingSystemUtils(),
       );
       testLogger.printWarning('Warning: Mild annoyance Will Robinson!');
@@ -85,6 +88,7 @@ void main() {
         androidSdk: FakeAndroidSdk(),
         buildSystem: TestBuildSystem.all(BuildResult(success: true)),
         fileSystem: MemoryFileSystem.test(),
+        logger: BufferLogger.test(),
         osUtils: FakeOperatingSystemUtils(),
       );
       testLogger.printWarning('Warning: Mild annoyance Will Robinson!');
@@ -103,6 +107,7 @@ void main() {
         androidSdk: FakeAndroidSdk(),
         buildSystem: TestBuildSystem.all(BuildResult(success: true)),
         fileSystem: MemoryFileSystem.test(),
+        logger: BufferLogger.test(),
         osUtils: FakeOperatingSystemUtils(),
       );
       testLogger.printError('Error: Danger Will Robinson!');
@@ -142,10 +147,11 @@ class FakeBuildCommand extends BuildCommand {
     required super.fileSystem,
     required super.buildSystem,
     required super.osUtils,
+    required Logger logger,
     required super.androidSdk,
     bool verboseHelp = false,
-  }) : super(verboseHelp: verboseHelp,) {
+  }) : super(logger: logger, verboseHelp: verboseHelp,) {
-    addSubcommand(FakeBuildSubcommand(verboseHelp: verboseHelp));
+    addSubcommand(FakeBuildSubcommand(logger: logger, verboseHelp: verboseHelp));
   }
 
   @override
@@ -161,7 +167,7 @@ class FakeBuildCommand extends BuildCommand {
 }
 
 class FakeBuildSubcommand extends BuildSubCommand {
-  FakeBuildSubcommand({required super.verboseHelp});
+  FakeBuildSubcommand({required super.logger, required super.verboseHelp});
 
   @override
   String get description => '';

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

@@ -5,6 +5,7 @@
 import 'package:args/command_runner.dart';
 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';
 import 'package:flutter_tools/src/build_system/build_system.dart';
@@ -49,6 +50,7 @@ void main() {
       androidSdk: FakeAndroidSdk(),
       buildSystem: TestBuildSystem.all(BuildResult(success: true)),
       fileSystem: MemoryFileSystem.test(),
+      logger: BufferLogger.test(),
       osUtils: FakeOperatingSystemUtils(),
     ));
 
@@ -68,6 +70,7 @@ void main() {
       androidSdk: FakeAndroidSdk(),
       buildSystem: TestBuildSystem.all(BuildResult(success: true)),
       fileSystem: fileSystem,
+      logger: BufferLogger.test(),
       osUtils: FakeOperatingSystemUtils(),
     ));
 
@@ -84,6 +87,7 @@ void main() {
       androidSdk: FakeAndroidSdk(),
       buildSystem: TestBuildSystem.all(BuildResult(success: true)),
       fileSystem: MemoryFileSystem.test(),
+      logger: BufferLogger.test(),
       osUtils: FakeOperatingSystemUtils(),
     ));
 
@@ -103,6 +107,7 @@ void main() {
       androidSdk: FakeAndroidSdk(),
       buildSystem: TestBuildSystem.all(BuildResult(success: true)),
       fileSystem: fileSystem,
+      logger: BufferLogger.test(),
       osUtils: FakeOperatingSystemUtils(),
     );
     final CommandRunner<void> runner = createTestCommandRunner(buildCommand);
@@ -143,6 +148,7 @@ void main() {
       androidSdk: FakeAndroidSdk(),
       buildSystem: TestBuildSystem.all(BuildResult(success: true)),
       fileSystem: fileSystem,
+      logger: BufferLogger.test(),
       osUtils: FakeOperatingSystemUtils(),
     );
     final CommandRunner<void> runner = createTestCommandRunner(buildCommand);
@@ -188,7 +194,7 @@ void main() {
   });
 
   testUsingContext('hidden if feature flag is not enabled', () async {
-    expect(BuildWebCommand(fileSystem: fileSystem, verboseHelp: false).hidden, true);
+    expect(BuildWebCommand(fileSystem: fileSystem, logger: BufferLogger.test(), verboseHelp: false).hidden, true);
   }, overrides: <Type, Generator>{
     Platform: () => fakePlatform,
     FileSystem: () => fileSystem,
@@ -197,7 +203,7 @@ void main() {
   });
 
   testUsingContext('not hidden if feature flag is enabled', () async {
-    expect(BuildWebCommand(fileSystem: fileSystem, verboseHelp: false).hidden, false);
+    expect(BuildWebCommand(fileSystem: fileSystem, logger: BufferLogger.test(), verboseHelp: false).hidden, false);
   }, overrides: <Type, Generator>{
     Platform: () => fakePlatform,
     FileSystem: () => fileSystem,
@@ -301,6 +307,7 @@ class TestWebBuildCommand extends FlutterCommand {
   TestWebBuildCommand({ required FileSystem fileSystem, bool verboseHelp = false }) :
     webCommand = BuildWebCommand(
       fileSystem: fileSystem,
+      logger: BufferLogger.test(),
       verboseHelp: verboseHelp) {
     addSubcommand(webCommand);
   }

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

@@ -5,6 +5,7 @@
 import 'package:file/memory.dart';
 import 'package:file_testing/file_testing.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/cache.dart';
 import 'package:flutter_tools/src/commands/build_windows.dart';
@@ -116,7 +117,7 @@ void main() {
   }
 
   testUsingContext('Windows build fails when there is no cmake path', () async {
-    final BuildWindowsCommand command = BuildWindowsCommand()
+    final BuildWindowsCommand command = BuildWindowsCommand(logger: BufferLogger.test())
       ..visualStudioOverride = FakeVisualStudio(cmakePath: null);
     setUpMockProjectFilesForBuild();
 
@@ -132,7 +133,7 @@ void main() {
 
   testUsingContext('Windows build fails when there is no windows project', () async {
     final FakeVisualStudio fakeVisualStudio = FakeVisualStudio();
-    final BuildWindowsCommand command = BuildWindowsCommand()
+    final BuildWindowsCommand command = BuildWindowsCommand(logger: BufferLogger.test())
       ..visualStudioOverride = fakeVisualStudio;
     setUpMockCoreProjectFiles();
 
@@ -150,7 +151,7 @@ void main() {
 
   testUsingContext('Windows build fails on non windows platform', () async {
     final FakeVisualStudio fakeVisualStudio = FakeVisualStudio();
-    final BuildWindowsCommand command = BuildWindowsCommand()
+    final BuildWindowsCommand command = BuildWindowsCommand(logger: BufferLogger.test())
       ..visualStudioOverride = fakeVisualStudio;
     setUpMockProjectFilesForBuild();
 
@@ -166,7 +167,7 @@ void main() {
 
   testUsingContext('Windows build fails when feature is disabled', () async {
     final FakeVisualStudio fakeVisualStudio = FakeVisualStudio();
-    final BuildWindowsCommand command = BuildWindowsCommand()
+    final BuildWindowsCommand command = BuildWindowsCommand(logger: BufferLogger.test())
       ..visualStudioOverride = fakeVisualStudio;
     setUpMockProjectFilesForBuild();
 
@@ -182,7 +183,7 @@ void main() {
 
   testUsingContext('Windows build does not spew stdout to status logger', () async {
     final FakeVisualStudio fakeVisualStudio = FakeVisualStudio();
-    final BuildWindowsCommand command = BuildWindowsCommand()
+    final BuildWindowsCommand command = BuildWindowsCommand(logger: BufferLogger.test())
       ..visualStudioOverride = fakeVisualStudio;
     setUpMockProjectFilesForBuild();
 
@@ -207,7 +208,7 @@ void main() {
 
   testUsingContext('Windows build extracts errors from stdout', () async {
     final FakeVisualStudio fakeVisualStudio = FakeVisualStudio();
-    final BuildWindowsCommand command = BuildWindowsCommand()
+    final BuildWindowsCommand command = BuildWindowsCommand(logger: BufferLogger.test())
       ..visualStudioOverride = fakeVisualStudio;
     setUpMockProjectFilesForBuild();
 
@@ -265,7 +266,7 @@ C:\foo\windows\runner\main.cpp(17,1): error C2065: 'Baz': undeclared identifier
 
   testUsingContext('Windows verbose build sets VERBOSE_SCRIPT_LOGGING', () async {
     final FakeVisualStudio fakeVisualStudio = FakeVisualStudio();
-    final BuildWindowsCommand command = BuildWindowsCommand()
+    final BuildWindowsCommand command = BuildWindowsCommand(logger: BufferLogger.test())
       ..visualStudioOverride = fakeVisualStudio;
     setUpMockProjectFilesForBuild();
 
@@ -291,7 +292,7 @@ C:\foo\windows\runner\main.cpp(17,1): error C2065: 'Baz': undeclared identifier
 
   testUsingContext('Windows build works around CMake generation bug', () async {
     final FakeVisualStudio fakeVisualStudio = FakeVisualStudio(displayVersion: '17.1.0');
-    final BuildWindowsCommand command = BuildWindowsCommand()
+    final BuildWindowsCommand command = BuildWindowsCommand(logger: BufferLogger.test())
       ..visualStudioOverride = fakeVisualStudio;
     setUpMockProjectFilesForBuild();
 
@@ -427,7 +428,7 @@ if %errorlevel% neq 0 goto :VCEnd</Command>
 
   testUsingContext('Windows build invokes build and writes generated files', () async {
     final FakeVisualStudio fakeVisualStudio = FakeVisualStudio();
-    final BuildWindowsCommand command = BuildWindowsCommand()
+    final BuildWindowsCommand command = BuildWindowsCommand(logger: BufferLogger.test())
       ..visualStudioOverride = fakeVisualStudio;
     setUpMockProjectFilesForBuild();
 
@@ -497,7 +498,7 @@ if %errorlevel% neq 0 goto :VCEnd</Command>
 
   testUsingContext('Windows profile build passes Profile configuration', () async {
     final FakeVisualStudio fakeVisualStudio = FakeVisualStudio();
-    final BuildWindowsCommand command = BuildWindowsCommand()
+    final BuildWindowsCommand command = BuildWindowsCommand(logger: BufferLogger.test())
       ..visualStudioOverride = fakeVisualStudio;
     setUpMockProjectFilesForBuild();
 
@@ -520,7 +521,7 @@ if %errorlevel% neq 0 goto :VCEnd</Command>
     const String generator = 'A different generator';
     final FakeVisualStudio fakeVisualStudio = FakeVisualStudio(
       cmakeGenerator: generator);
-    final BuildWindowsCommand command = BuildWindowsCommand()
+    final BuildWindowsCommand command = BuildWindowsCommand(logger: BufferLogger.test())
       ..visualStudioOverride = fakeVisualStudio;
     setUpMockProjectFilesForBuild();
 
@@ -541,7 +542,7 @@ if %errorlevel% neq 0 goto :VCEnd</Command>
 
   testUsingContext("Windows build uses pubspec's version", () async {
     final FakeVisualStudio fakeVisualStudio = FakeVisualStudio();
-    final BuildWindowsCommand command = BuildWindowsCommand()
+    final BuildWindowsCommand command = BuildWindowsCommand(logger: BufferLogger.test())
       ..visualStudioOverride = fakeVisualStudio;
     setUpMockProjectFilesForBuild();
 
@@ -587,7 +588,7 @@ if %errorlevel% neq 0 goto :VCEnd</Command>
 
   testUsingContext('Windows build uses build-name and build-number', () async {
     final FakeVisualStudio fakeVisualStudio = FakeVisualStudio();
-    final BuildWindowsCommand command = BuildWindowsCommand()
+    final BuildWindowsCommand command = BuildWindowsCommand(logger: BufferLogger.test())
       ..visualStudioOverride = fakeVisualStudio;
     setUpMockProjectFilesForBuild();
 
@@ -631,7 +632,7 @@ if %errorlevel% neq 0 goto :VCEnd</Command>
 
   testUsingContext('Windows build build-name overrides pubspec', () async {
     final FakeVisualStudio fakeVisualStudio = FakeVisualStudio();
-    final BuildWindowsCommand command = BuildWindowsCommand()
+    final BuildWindowsCommand command = BuildWindowsCommand(logger: BufferLogger.test())
       ..visualStudioOverride = fakeVisualStudio;
     setUpMockProjectFilesForBuild();
 
@@ -678,7 +679,7 @@ if %errorlevel% neq 0 goto :VCEnd</Command>
 
   testUsingContext('Windows build build-number overrides pubspec', () async {
     final FakeVisualStudio fakeVisualStudio = FakeVisualStudio();
-    final BuildWindowsCommand command = BuildWindowsCommand()
+    final BuildWindowsCommand command = BuildWindowsCommand(logger: BufferLogger.test())
       ..visualStudioOverride = fakeVisualStudio;
     setUpMockProjectFilesForBuild();
 
@@ -725,7 +726,7 @@ if %errorlevel% neq 0 goto :VCEnd</Command>
 
   testUsingContext('Windows build build-name and build-number override pubspec', () async {
     final FakeVisualStudio fakeVisualStudio = FakeVisualStudio();
-    final BuildWindowsCommand command = BuildWindowsCommand()
+    final BuildWindowsCommand command = BuildWindowsCommand(logger: BufferLogger.test())
       ..visualStudioOverride = fakeVisualStudio;
     setUpMockProjectFilesForBuild();
 
@@ -773,7 +774,7 @@ if %errorlevel% neq 0 goto :VCEnd</Command>
 
   testUsingContext('Windows build warns on non-numeric build-number', () async {
     final FakeVisualStudio fakeVisualStudio = FakeVisualStudio();
-    final BuildWindowsCommand command = BuildWindowsCommand()
+    final BuildWindowsCommand command = BuildWindowsCommand(logger: BufferLogger.test())
       ..visualStudioOverride = fakeVisualStudio;
     setUpMockProjectFilesForBuild();
 
@@ -823,7 +824,7 @@ if %errorlevel% neq 0 goto :VCEnd</Command>
 
   testUsingContext('Windows build warns on complex build-number', () async {
     final FakeVisualStudio fakeVisualStudio = FakeVisualStudio();
-    final BuildWindowsCommand command = BuildWindowsCommand()
+    final BuildWindowsCommand command = BuildWindowsCommand(logger: BufferLogger.test())
       ..visualStudioOverride = fakeVisualStudio;
     setUpMockProjectFilesForBuild();
 
@@ -872,14 +873,14 @@ if %errorlevel% neq 0 goto :VCEnd</Command>
   });
 
   testUsingContext('hidden when not enabled on Windows host', () {
-    expect(BuildWindowsCommand().hidden, true);
+    expect(BuildWindowsCommand(logger: BufferLogger.test()).hidden, true);
   }, overrides: <Type, Generator>{
     FeatureFlags: () => TestFeatureFlags(),
     Platform: () => windowsPlatform,
   });
 
   testUsingContext('Not hidden when enabled and on Windows host', () {
-    expect(BuildWindowsCommand().hidden, false);
+    expect(BuildWindowsCommand(logger: BufferLogger.test()).hidden, false);
   }, overrides: <Type, Generator>{
     FeatureFlags: () => TestFeatureFlags(isWindowsEnabled: true),
     Platform: () => windowsPlatform,
@@ -887,7 +888,7 @@ if %errorlevel% neq 0 goto :VCEnd</Command>
 
   testUsingContext('Performs code size analysis and sends analytics', () async {
     final FakeVisualStudio fakeVisualStudio = FakeVisualStudio();
-    final BuildWindowsCommand command = BuildWindowsCommand()
+    final BuildWindowsCommand command = BuildWindowsCommand(logger: BufferLogger.test())
       ..visualStudioOverride = fakeVisualStudio;
     setUpMockProjectFilesForBuild();
 
@@ -939,7 +940,7 @@ if %errorlevel% neq 0 goto :VCEnd</Command>
   // is resolved on the VS side, we can allow these paths again
   testUsingContext('Test bad path characters', () async {
     final FakeVisualStudio fakeVisualStudio = FakeVisualStudio();
-    final BuildWindowsCommand command = BuildWindowsCommand()
+    final BuildWindowsCommand command = BuildWindowsCommand(logger: BufferLogger.test())
       ..visualStudioOverride = fakeVisualStudio;
     fileSystem.currentDirectory = fileSystem.directory("test_'path")
       ..createSync();

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

@@ -381,6 +381,7 @@ void main() {
       '--trace-skia',
       '--trace-systrace',
       '--verbose-system-logs',
+      '--null-assertions',
       '--native-null-assertions',
       '--enable-impeller',
       '--trace-systrace',
@@ -396,6 +397,7 @@ void main() {
     expect(options.traceSkia, true);
     expect(options.traceSystrace, true);
     expect(options.verboseSystemLogs, true);
+    expect(options.nullAssertions, true);
     expect(options.nativeNullAssertions, true);
     expect(options.enableImpeller, true);
     expect(options.traceSystrace, true);

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

@@ -1005,6 +1005,7 @@ void main() {
       '--trace-skia',
       '--trace-systrace',
       '--verbose-system-logs',
+      '--null-assertions',
       '--native-null-assertions',
       '--enable-impeller',
       '--trace-systrace',
@@ -1021,6 +1022,7 @@ void main() {
     expect(options.traceSkia, true);
     expect(options.traceSystrace, true);
     expect(options.verboseSystemLogs, true);
+    expect(options.nullAssertions, true);
     expect(options.nativeNullAssertions, true);
     expect(options.traceSystrace, true);
     expect(options.enableImpeller, true);

packages/flutter_tools/test/commands.shard/permeable/build_aar_test.dart

@@ -7,6 +7,7 @@ import 'package:flutter_tools/src/android/android_builder.dart';
 import 'package:flutter_tools/src/android/android_sdk.dart';
 import 'package:flutter_tools/src/android/android_studio.dart';
 import 'package:flutter_tools/src/base/file_system.dart';
+import 'package:flutter_tools/src/base/logger.dart';
 import 'package:flutter_tools/src/build_info.dart';
 import 'package:flutter_tools/src/cache.dart';
 import 'package:flutter_tools/src/commands/build_aar.dart';
@@ -30,6 +31,7 @@ void main() {
     final BuildAarCommand command = BuildAarCommand(
       androidSdk: FakeAndroidSdk(),
       fileSystem: globals.fs,
+      logger: BufferLogger.test(),
       verboseHelp: false,
     );
     final CommandRunner<void> runner = createTestCommandRunner(command);
@@ -187,6 +189,7 @@ void main() {
       expect(buildInfo.splitDebugInfoPath, '/project-name/v1.2.3/');
       expect(buildInfo.dartObfuscation, isTrue);
       expect(buildInfo.dartDefines.contains('foo=bar'), isTrue);
+      expect(buildInfo.nullSafetyMode, NullSafetyMode.sound);
     }, overrides: <Type, Generator>{
       AndroidBuilder: () => fakeAndroidBuilder,
     });
@@ -306,6 +309,7 @@ Future<BuildAarCommand> runBuildAarCommand(
   final BuildAarCommand command = BuildAarCommand(
     androidSdk: androidSdk,
     fileSystem: globals.fs,
+    logger: BufferLogger.test(),
     verboseHelp: false,
   );
   final CommandRunner<void> runner = createTestCommandRunner(command);

packages/flutter_tools/test/commands.shard/permeable/build_apk_test.dart

@@ -7,6 +7,7 @@ import 'package:flutter_tools/src/android/android_builder.dart';
 import 'package:flutter_tools/src/android/android_sdk.dart';
 import 'package:flutter_tools/src/android/android_studio.dart';
 import 'package:flutter_tools/src/base/file_system.dart';
+import 'package:flutter_tools/src/base/logger.dart';
 import 'package:flutter_tools/src/cache.dart';
 import 'package:flutter_tools/src/commands/build_apk.dart';
 import 'package:flutter_tools/src/globals.dart' as globals;
@@ -429,7 +430,7 @@ Future<BuildApkCommand> runBuildApkCommand(
   String target, {
   List<String>? arguments,
 }) async {
-  final BuildApkCommand command = BuildApkCommand();
+  final BuildApkCommand command = BuildApkCommand(logger: BufferLogger.test());
   final CommandRunner<void> runner = createTestCommandRunner(command);
   await runner.run(<String>[
     'apk',

packages/flutter_tools/test/commands.shard/permeable/build_appbundle_test.dart

@@ -6,6 +6,7 @@ import 'package:args/command_runner.dart';
 import 'package:flutter_tools/src/android/android_builder.dart';
 import 'package:flutter_tools/src/android/android_sdk.dart';
 import 'package:flutter_tools/src/base/file_system.dart';
+import 'package:flutter_tools/src/base/logger.dart';
 import 'package:flutter_tools/src/cache.dart';
 import 'package:flutter_tools/src/commands/build_appbundle.dart';
 import 'package:flutter_tools/src/globals.dart' as globals;
@@ -213,7 +214,7 @@ Future<BuildAppBundleCommand> runBuildAppBundleCommand(
   String target, {
   List<String>? arguments,
 }) async {
-  final BuildAppBundleCommand command = BuildAppBundleCommand();
+  final BuildAppBundleCommand command = BuildAppBundleCommand(logger: BufferLogger.test());
   final CommandRunner<void> runner = createTestCommandRunner(command);
   await runner.run(<String>[
     'appbundle',

packages/flutter_tools/test/commands.shard/permeable/build_bundle_test.dart

@@ -5,6 +5,7 @@
 import 'package:args/command_runner.dart';
 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/build_info.dart';
 import 'package:flutter_tools/src/build_system/build_system.dart';
 import 'package:flutter_tools/src/bundle.dart';
@@ -46,6 +47,7 @@ void main() {
 
   Future<BuildBundleCommand> runCommandIn(String projectPath, { List<String>? arguments }) async {
     final BuildBundleCommand command = BuildBundleCommand(
+        logger: BufferLogger.test(),
         bundleBuilder: fakeBundleBuilder,
     );
     final CommandRunner<void> runner = createTestCommandRunner(command);
@@ -89,7 +91,9 @@ void main() {
     globals.fs.file(globals.fs.path.join('lib', 'main.dart')).createSync(recursive: true);
     globals.fs.file('pubspec.yaml').createSync(recursive: true);
     globals.fs.file('.packages').createSync(recursive: true);
-    final CommandRunner<void> runner = createTestCommandRunner(BuildBundleCommand());
+    final CommandRunner<void> runner = createTestCommandRunner(BuildBundleCommand(
+      logger: BufferLogger.test(),
+    ));
 
     expect(() => runner.run(<String>[
       'bundle',
@@ -107,7 +111,9 @@ void main() {
     globals.fs.file(globals.fs.path.join('lib', 'main.dart')).createSync(recursive: true);
     globals.fs.file('pubspec.yaml').createSync();
     globals.fs.file('.packages').createSync();
-    final CommandRunner<void> runner = createTestCommandRunner(BuildBundleCommand());
+    final CommandRunner<void> runner = createTestCommandRunner(BuildBundleCommand(
+      logger: BufferLogger.test(),
+    ));
 
     expect(() => runner.run(<String>[
       'bundle',
@@ -125,7 +131,9 @@ void main() {
     globals.fs.file(globals.fs.path.join('lib', 'main.dart')).createSync(recursive: true);
     globals.fs.file('pubspec.yaml').createSync();
     globals.fs.file('.packages').createSync();
-    final CommandRunner<void> runner = createTestCommandRunner(BuildBundleCommand());
+    final CommandRunner<void> runner = createTestCommandRunner(BuildBundleCommand(
+      logger: BufferLogger.test(),
+    ));
 
     expect(() => runner.run(<String>[
       'bundle',
@@ -143,7 +151,9 @@ void main() {
     globals.fs.file(globals.fs.path.join('lib', 'main.dart')).createSync(recursive: true);
     globals.fs.file('pubspec.yaml').createSync();
     globals.fs.file('.packages').createSync();
-    final CommandRunner<void> runner = createTestCommandRunner(BuildBundleCommand());
+    final CommandRunner<void> runner = createTestCommandRunner(BuildBundleCommand(
+      logger: BufferLogger.test(),
+    ));
 
     expect(() => runner.run(<String>[
       'bundle',
@@ -160,7 +170,9 @@ void main() {
     globals.fs.file(globals.fs.path.join('lib', 'main.dart')).createSync(recursive: true);
     globals.fs.file('pubspec.yaml').createSync();
     globals.fs.file('.packages').createSync();
-    final CommandRunner<void> runner = createTestCommandRunner(BuildBundleCommand());
+    final CommandRunner<void> runner = createTestCommandRunner(BuildBundleCommand(
+      logger: BufferLogger.test(),
+    ));
 
     await runner.run(<String>[
       'bundle',
@@ -178,7 +190,9 @@ void main() {
     globals.fs.file(globals.fs.path.join('lib', 'main.dart')).createSync(recursive: true);
     globals.fs.file('pubspec.yaml').createSync();
     globals.fs.file('.packages').createSync();
-    final CommandRunner<void> runner = createTestCommandRunner(BuildBundleCommand());
+    final CommandRunner<void> runner = createTestCommandRunner(BuildBundleCommand(
+      logger: BufferLogger.test(),
+    ));
 
     await runner.run(<String>[
       'bundle',
@@ -196,7 +210,9 @@ void main() {
     globals.fs.file(globals.fs.path.join('lib', 'main.dart')).createSync(recursive: true);
     globals.fs.file('pubspec.yaml').createSync();
     globals.fs.file('.packages').createSync();
-    final CommandRunner<void> runner = createTestCommandRunner(BuildBundleCommand());
+    final CommandRunner<void> runner = createTestCommandRunner(BuildBundleCommand(
+      logger: BufferLogger.test(),
+    ));
 
     await runner.run(<String>[
       'bundle',
@@ -214,7 +230,9 @@ void main() {
     globals.fs.file(globals.fs.path.join('lib', 'main.dart')).createSync(recursive: true);
     globals.fs.file('pubspec.yaml').createSync();
     globals.fs.file('.packages').createSync();
-    final CommandRunner<void> runner = createTestCommandRunner(BuildBundleCommand());
+    final CommandRunner<void> runner = createTestCommandRunner(BuildBundleCommand(
+      logger: BufferLogger.test(),
+    ));
 
     await runner.run(<String>[
       'bundle',
@@ -244,7 +262,9 @@ void main() {
     globals.fs.file(globals.fs.path.join('lib', 'main.dart')).createSync(recursive: true);
     globals.fs.file('pubspec.yaml').createSync();
     globals.fs.file('.packages').createSync();
-    final CommandRunner<void> runner = createTestCommandRunner(BuildBundleCommand());
+    final CommandRunner<void> runner = createTestCommandRunner(BuildBundleCommand(
+      logger: BufferLogger.test(),
+    ));
 
     await runner.run(<String>[
       'bundle',
@@ -275,7 +295,9 @@ void main() {
     globals.fs.file(globals.fs.path.join('lib', 'main.dart')).createSync(recursive: true);
     globals.fs.file('pubspec.yaml').createSync();
     globals.fs.file('.packages').createSync();
-    final CommandRunner<void> runner = createTestCommandRunner(BuildBundleCommand());
+    final CommandRunner<void> runner = createTestCommandRunner(BuildBundleCommand(
+      logger: BufferLogger.test(),
+    ));
 
     await runner.run(<String>[
       'bundle',
@@ -305,7 +327,9 @@ void main() {
     globals.fs.file(globals.fs.path.join('lib', 'main.dart')).createSync(recursive: true);
     globals.fs.file('pubspec.yaml').createSync();
     globals.fs.file('.packages').createSync();
-    final CommandRunner<void> runner = createTestCommandRunner(BuildBundleCommand());
+    final CommandRunner<void> runner = createTestCommandRunner(BuildBundleCommand(
+      logger: BufferLogger.test(),
+    ));
 
     await runner.run(<String>[
       'bundle',
@@ -336,7 +360,9 @@ void main() {
     globals.fs.file(globals.fs.path.join('lib', 'main.dart')).createSync(recursive: true);
     globals.fs.file('pubspec.yaml').createSync();
     globals.fs.file('.packages').createSync();
-    final CommandRunner<void> runner = createTestCommandRunner(BuildBundleCommand());
+    final CommandRunner<void> runner = createTestCommandRunner(BuildBundleCommand(
+      logger: BufferLogger.test(),
+    ));
 
     await runner.run(<String>[
       'bundle',
@@ -367,7 +393,9 @@ void main() {
     globals.fs.file(globals.fs.path.join('lib', 'main.dart')).createSync(recursive: true);
     globals.fs.file('pubspec.yaml').createSync();
     globals.fs.file('.packages').createSync();
-    final CommandRunner<void> runner = createTestCommandRunner(BuildBundleCommand());
+    final CommandRunner<void> runner = createTestCommandRunner(BuildBundleCommand(
+      logger: BufferLogger.test(),
+    ));
 
     await runner.run(<String>[
       'bundle',
@@ -398,7 +426,9 @@ void main() {
     globals.fs.file(globals.fs.path.join('lib', 'main.dart')).createSync(recursive: true);
     globals.fs.file('pubspec.yaml').createSync();
     globals.fs.file('.packages').createSync();
-    final CommandRunner<void> runner = createTestCommandRunner(BuildBundleCommand());
+    final CommandRunner<void> runner = createTestCommandRunner(BuildBundleCommand(
+      logger: BufferLogger.test(),
+    ));
 
     await runner.run(<String>[
       'bundle',
@@ -437,7 +467,9 @@ void main() {
     globals.fs.file(globals.fs.path.join('lib', 'main.dart')).createSync(recursive: true);
     globals.fs.file('pubspec.yaml').createSync();
     globals.fs.file('.packages').createSync();
-    final CommandRunner<void> runner = createTestCommandRunner(BuildBundleCommand());
+    final CommandRunner<void> runner = createTestCommandRunner(BuildBundleCommand(
+      logger: BufferLogger.test(),
+    ));
 
     await runner.run(<String>[
       'bundle',
@@ -493,7 +525,9 @@ void main() {
         }
       '''
     );
-    final CommandRunner<void> runner = createTestCommandRunner(BuildBundleCommand());
+    final CommandRunner<void> runner = createTestCommandRunner(BuildBundleCommand(
+      logger: BufferLogger.test(),
+    ));
 
     await runner.run(<String>[
       'bundle',
@@ -530,7 +564,9 @@ void main() {
         }
       '''
     );
-    final CommandRunner<void> runner = createTestCommandRunner(BuildBundleCommand());
+    final CommandRunner<void> runner = createTestCommandRunner(BuildBundleCommand(
+      logger: BufferLogger.test(),
+    ));
 
     await runner.run(<String>[
       'bundle',
@@ -551,7 +587,9 @@ void main() {
     globals.fs.file('pubspec.yaml').createSync();
     globals.fs.file('.packages').createSync();
     globals.fs.directory('config').createSync();
-    final CommandRunner<void> runner = createTestCommandRunner(BuildBundleCommand());
+    final CommandRunner<void> runner = createTestCommandRunner(BuildBundleCommand(
+      logger: BufferLogger.test(),
+    ));
 
     expect(() => runner.run(<String>[
       'bundle',
@@ -578,7 +616,9 @@ void main() {
         }
       '''
     );
-    final CommandRunner<void> runner = createTestCommandRunner(BuildBundleCommand());
+    final CommandRunner<void> runner = createTestCommandRunner(BuildBundleCommand(
+      logger: BufferLogger.test(),
+    ));
 
     expect(() => runner.run(<String>[
       'bundle',

packages/flutter_tools/test/general.shard/analytics_test.dart

@@ -9,6 +9,7 @@ import 'package:flutter_tools/src/android/android_workflow.dart';
 import 'package:flutter_tools/src/base/config.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/platform.dart';
 import 'package:flutter_tools/src/base/time.dart';
 import 'package:flutter_tools/src/build_system/build_system.dart';
@@ -219,6 +220,7 @@ void main() {
         androidSdk: FakeAndroidSdk(),
         buildSystem: TestBuildSystem.all(BuildResult(success: true)),
         fileSystem: MemoryFileSystem.test(),
+        logger: BufferLogger.test(),
         osUtils: FakeOperatingSystemUtils(),
       );
       final FlutterCommand buildApkCommand = buildCommand.subcommands['apk']! as FlutterCommand;

packages/flutter_tools/test/general.shard/android/android_device_start_test.dart

@@ -250,7 +250,7 @@ void main() {
         '--ez', 'verify-entry-points', 'true',
         '--ez', 'start-paused', 'true',
         '--ez', 'disable-service-auth-codes', 'true',
-        '--es', 'dart-flags', 'foo',
+        '--es', 'dart-flags', 'foo,--null_assertions',
         '--ez', 'use-test-fonts', 'true',
         '--ez', 'verbose-logging', 'true',
         '--user', '10',
@@ -278,6 +278,7 @@ void main() {
         purgePersistentCache: true,
         useTestFonts: true,
         verboseSystemLogs: true,
+        nullAssertions: true,
         enableImpeller: true,
       ),
       platformArgs: <String, dynamic>{},

packages/flutter_tools/test/general.shard/artifacts_test.dart

@@ -152,6 +152,22 @@ void main() {
     });
 
     testWithoutContext('precompiled web artifact paths are correct', () {
+      expect(
+        artifacts.getHostArtifact(HostArtifact.webPrecompiledSdk).path,
+        'root/bin/cache/flutter_web_sdk/kernel/amd/dart_sdk.js',
+      );
+      expect(
+        artifacts.getHostArtifact(HostArtifact.webPrecompiledSdkSourcemaps).path,
+        'root/bin/cache/flutter_web_sdk/kernel/amd/dart_sdk.js.map',
+      );
+      expect(
+        artifacts.getHostArtifact(HostArtifact.webPrecompiledCanvaskitSdk).path,
+        'root/bin/cache/flutter_web_sdk/kernel/amd-canvaskit/dart_sdk.js',
+      );
+      expect(
+        artifacts.getHostArtifact(HostArtifact.webPrecompiledCanvaskitSdkSourcemaps).path,
+        'root/bin/cache/flutter_web_sdk/kernel/amd-canvaskit/dart_sdk.js.map',
+      );
       expect(
         artifacts.getHostArtifact(HostArtifact.webPrecompiledSoundSdk).path,
         'root/bin/cache/flutter_web_sdk/kernel/amd-sound/dart_sdk.js',

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

@@ -2,13 +2,29 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+import 'package:args/args.dart';
 import 'package:args/command_runner.dart';
 import 'package:file/memory.dart';
+import 'package:flutter_tools/src/artifacts.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/platform.dart';
+import 'package:flutter_tools/src/base/signals.dart';
 import 'package:flutter_tools/src/base/terminal.dart';
 import 'package:flutter_tools/src/build_info.dart';
 import 'package:flutter_tools/src/build_system/build_system.dart';
+import 'package:flutter_tools/src/commands/attach.dart';
 import 'package:flutter_tools/src/commands/build.dart';
+import 'package:flutter_tools/src/commands/build_aar.dart';
+import 'package:flutter_tools/src/commands/build_apk.dart';
+import 'package:flutter_tools/src/commands/build_appbundle.dart';
+import 'package:flutter_tools/src/commands/build_ios.dart';
+import 'package:flutter_tools/src/commands/build_ios_framework.dart';
+import 'package:flutter_tools/src/commands/build_linux.dart';
+import 'package:flutter_tools/src/commands/build_macos.dart';
+import 'package:flutter_tools/src/commands/build_web.dart';
+import 'package:flutter_tools/src/commands/build_windows.dart';
 import 'package:flutter_tools/src/runner/flutter_command.dart';
 import 'package:test/fake.dart';
 
@@ -30,11 +46,78 @@ class FakeProcessInfo extends Fake implements ProcessInfo {
 }
 
 void main() {
+  testUsingContext('All build commands support null safety options', () {
+    final FileSystem fileSystem = MemoryFileSystem.test();
+    final Platform platform = FakePlatform();
+    final BufferLogger logger = BufferLogger.test();
+    final List<FlutterCommand> commands = <FlutterCommand>[
+      BuildWindowsCommand(logger: BufferLogger.test()),
+      BuildLinuxCommand(logger: BufferLogger.test(), operatingSystemUtils: FakeOperatingSystemUtils()),
+      BuildMacosCommand(logger: BufferLogger.test(), verboseHelp: false),
+      BuildWebCommand(fileSystem: fileSystem, logger: BufferLogger.test(), verboseHelp: false),
+      BuildApkCommand(logger: BufferLogger.test()),
+      BuildIOSCommand(logger: BufferLogger.test(), verboseHelp: false),
+      BuildIOSArchiveCommand(logger: BufferLogger.test(), verboseHelp: false),
+      BuildAppBundleCommand(logger: BufferLogger.test()),
+      BuildAarCommand(
+        logger: BufferLogger.test(),
+        androidSdk: FakeAndroidSdk(),
+        fileSystem: fileSystem,
+        verboseHelp: false,
+      ),
+      BuildIOSFrameworkCommand(
+        logger: BufferLogger.test(),
+        verboseHelp: false,
+        buildSystem: FlutterBuildSystem(
+          fileSystem: fileSystem,
+          platform: platform,
+          logger: logger,
+        ),
+      ),
+      AttachCommand(
+        artifacts: Artifacts.test(),
+        stdio: FakeStdio(),
+        logger: logger,
+        terminal: FakeTerminal(),
+        signals: Signals.test(),
+        platform: platform,
+        processInfo: FakeProcessInfo(),
+        fileSystem: MemoryFileSystem.test(),
+      ),
+    ];
+
+    for (final FlutterCommand command in commands) {
+      final ArgResults results = command.argParser.parse(<String>[
+        '--sound-null-safety',
+        '--enable-experiment=non-nullable',
+      ]);
+
+      expect(results.wasParsed('sound-null-safety'), true);
+      expect(results.wasParsed('enable-experiment'), true);
+    }
+  });
+
+  testUsingContext('BuildSubCommand displays current null safety mode',
+      () async {
+    const BuildInfo unsound = BuildInfo(
+      BuildMode.debug,
+      '',
+      nullSafetyMode: NullSafetyMode.unsound,
+      treeShakeIcons: false,
+    );
+
+    final BufferLogger logger = BufferLogger.test();
+    FakeBuildSubCommand(logger).test(unsound);
+    expect(logger.statusText,
+        contains('Building without sound null safety ⚠️'));
+  });
+
   testUsingContext('Include only supported sub commands', () {
     final BuildCommand command = BuildCommand(
       androidSdk: FakeAndroidSdk(),
       buildSystem: TestBuildSystem.all(BuildResult(success: true)),
       fileSystem: MemoryFileSystem.test(),
+      logger: BufferLogger.test(),
       osUtils: FakeOperatingSystemUtils(),
     );
     for (final Command<void> x in command.subcommands.values) {
@@ -44,7 +127,7 @@ void main() {
 }
 
 class FakeBuildSubCommand extends BuildSubCommand {
-  FakeBuildSubCommand() : super(verboseHelp: false);
+  FakeBuildSubCommand(Logger logger) : super(logger: logger, verboseHelp: false);
 
   @override
   String get description => throw UnimplementedError();
@@ -53,8 +136,7 @@ class FakeBuildSubCommand extends BuildSubCommand {
   String get name => throw UnimplementedError();
 
   void test(BuildInfo buildInfo) {
-    throw UnimplementedError('TODO what should we do here?');
+    displayNullSafetyMode(buildInfo);
-    //displayNullSafetyMode(buildInfo);
   }
 
   @override

packages/flutter_tools/test/general.shard/desktop_device_test.dart

@@ -159,9 +159,10 @@ void main() {
           'FLUTTER_ENGINE_SWITCH_14': 'verify-entry-points=true',
           'FLUTTER_ENGINE_SWITCH_15': 'start-paused=true',
           'FLUTTER_ENGINE_SWITCH_16': 'disable-service-auth-codes=true',
-          'FLUTTER_ENGINE_SWITCH_17': 'use-test-fonts=true',
+          'FLUTTER_ENGINE_SWITCH_17': 'dart-flags=--null_assertions',
-          'FLUTTER_ENGINE_SWITCH_18': 'verbose-logging=true',
+          'FLUTTER_ENGINE_SWITCH_18': 'use-test-fonts=true',
-          'FLUTTER_ENGINE_SWITCHES': '18',
+          'FLUTTER_ENGINE_SWITCH_19': 'verbose-logging=true',
+          'FLUTTER_ENGINE_SWITCHES': '19',
         }
       ),
     ]);
@@ -189,6 +190,7 @@ void main() {
         purgePersistentCache: true,
         useTestFonts: true,
         verboseSystemLogs: true,
+        nullAssertions: true,
       ),
     );
 

packages/flutter_tools/test/general.shard/device_test.dart

@@ -701,9 +701,11 @@ void main() {
     });
   });
 
-  testWithoutContext('computeDartVmFlags handles various combinations of Dart VM flags', () {
+  testWithoutContext('computeDartVmFlags handles various combinations of Dart VM flags and null_assertions', () {
     expect(computeDartVmFlags(DebuggingOptions.enabled(BuildInfo.debug)), '');
     expect(computeDartVmFlags(DebuggingOptions.enabled(BuildInfo.debug, dartFlags: '--foo')), '--foo');
+    expect(computeDartVmFlags(DebuggingOptions.enabled(BuildInfo.debug, nullAssertions: true)), '--null_assertions');
+    expect(computeDartVmFlags(DebuggingOptions.enabled(BuildInfo.debug, dartFlags: '--foo', nullAssertions: true)), '--foo,--null_assertions');
   });
 
   group('JSON encode DebuggingOptions', () {
@@ -755,6 +757,7 @@ void main() {
         cacheSkSL: true,
         purgePersistentCache: true,
         verboseSystemLogs: true,
+        nullAssertions: true,
         enableImpeller: true,
         deviceVmServicePort: 0,
         hostVmServicePort: 1,
@@ -775,7 +778,7 @@ void main() {
           '--disable-service-auth-codes',
           '--disable-vm-service-publication',
           '--start-paused',
-          '--dart-flags="--foo"',
+          '--dart-flags="--foo,--null_assertions"',
           '--use-test-fonts',
           '--enable-checked-mode',
           '--verify-entry-points',
@@ -914,6 +917,7 @@ void main() {
         cacheSkSL: true,
         purgePersistentCache: true,
         verboseSystemLogs: true,
+        nullAssertions: true,
         enableImpeller: true,
         deviceVmServicePort: 0,
         hostVmServicePort: 1,
@@ -934,7 +938,7 @@ void main() {
           '--disable-service-auth-codes',
           '--disable-vm-service-publication',
           '--start-paused',
-          '--dart-flags=--foo',
+          '--dart-flags=--foo,--null_assertions',
           '--use-test-fonts',
           '--enable-checked-mode',
           '--verify-entry-points',

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

@@ -337,7 +337,7 @@ void main() {
             '--disable-service-auth-codes',
             '--disable-vm-service-publication',
             '--start-paused',
-            '--dart-flags="--foo"',
+            '--dart-flags="--foo,--null_assertions"',
             '--use-test-fonts',
             '--enable-checked-mode',
             '--verify-entry-points',
@@ -404,6 +404,7 @@ void main() {
         cacheSkSL: true,
         purgePersistentCache: true,
         verboseSystemLogs: true,
+        nullAssertions: true,
         enableImpeller: true,
         enableEmbedderApi: true,
       ),

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

@@ -1041,6 +1041,7 @@ Dec 20 17:04:32 md32-11-vm1 Another App[88374]: Ignore this text'''
         cacheSkSL: true,
         purgePersistentCache: true,
         dartFlags: '--baz',
+        nullAssertions: true,
         enableImpeller: true,
         hostVmServicePort: 0,
       );
@@ -1064,7 +1065,7 @@ Dec 20 17:04:32 md32-11-vm1 Another App[88374]: Ignore this text'''
         '--verbose-logging',
         '--cache-sksl',
         '--purge-persistent-cache',
-        '--dart-flags=--baz',
+        '--dart-flags=--baz,--null_assertions',
         '--enable-impeller',
         '--vm-service-port=0',
       ]));

packages/flutter_tools/test/general.shard/reporting/events_test.dart

@@ -2,8 +2,10 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+import 'package:flutter_tools/src/build_info.dart';
 import 'package:flutter_tools/src/doctor_validator.dart';
 import 'package:flutter_tools/src/reporting/reporting.dart';
+import 'package:package_config/package_config.dart';
 
 import '../../src/common.dart';
 
@@ -54,6 +56,74 @@ void main() {
       const TestUsageEvent('doctor-result', 'FakeGroupedValidator', label: 'crash'),
     ));
   });
+
+  testWithoutContext('Reports null safe analytics events', () {
+    final TestUsage usage = TestUsage();
+    final PackageConfig packageConfig = PackageConfig(<Package>[
+      Package('foo', Uri.parse('file:///foo/'), languageVersion: LanguageVersion(2, 12)),
+      Package('bar', Uri.parse('file:///fizz/'), languageVersion: LanguageVersion(2, 1)),
+      Package('baz', Uri.parse('file:///bar/'), languageVersion: LanguageVersion(2, 2)),
+    ]);
+
+    NullSafetyAnalysisEvent(
+      packageConfig,
+      NullSafetyMode.sound,
+      'foo',
+      usage,
+    ).send();
+
+    expect(usage.events, unorderedEquals(<TestUsageEvent>[
+      const TestUsageEvent(NullSafetyAnalysisEvent.kNullSafetyCategory, 'runtime-mode', label: 'NullSafetyMode.sound'),
+      TestUsageEvent(NullSafetyAnalysisEvent.kNullSafetyCategory, 'stats', parameters: CustomDimensions.fromMap(<String, String>{
+      'cd49': '1', 'cd50': '3',
+      })),
+      const TestUsageEvent(NullSafetyAnalysisEvent.kNullSafetyCategory, 'language-version', label: '2.12'),
+    ]));
+  });
+
+  testWithoutContext('Does not crash if main package is missing', () {
+    final TestUsage usage = TestUsage();
+    final PackageConfig packageConfig = PackageConfig(<Package>[
+      Package('foo', Uri.parse('file:///foo/lib/'), languageVersion: LanguageVersion(2, 12)),
+      Package('bar', Uri.parse('file:///fizz/lib/'), languageVersion: LanguageVersion(2, 1)),
+      Package('baz', Uri.parse('file:///bar/lib/'), languageVersion: LanguageVersion(2, 2)),
+    ]);
+
+    NullSafetyAnalysisEvent(
+      packageConfig,
+      NullSafetyMode.sound,
+      'something-unrelated',
+      usage,
+    ).send();
+
+    expect(usage.events, unorderedEquals(<TestUsageEvent>[
+      const TestUsageEvent(NullSafetyAnalysisEvent.kNullSafetyCategory, 'runtime-mode', label: 'NullSafetyMode.sound'),
+      TestUsageEvent(NullSafetyAnalysisEvent.kNullSafetyCategory, 'stats', parameters: CustomDimensions.fromMap(<String, String>{
+        'cd49': '1', 'cd50': '3',
+      })),
+    ]));
+  });
+
+  testWithoutContext('a null language version is treated as unmigrated', () {
+    final TestUsage usage = TestUsage();
+    final PackageConfig packageConfig = PackageConfig(<Package>[
+      Package('foo', Uri.parse('file:///foo/lib/')),
+    ]);
+
+    NullSafetyAnalysisEvent(
+      packageConfig,
+      NullSafetyMode.sound,
+      'something-unrelated',
+      usage,
+    ).send();
+
+    expect(usage.events, unorderedEquals(<TestUsageEvent>[
+      const TestUsageEvent(NullSafetyAnalysisEvent.kNullSafetyCategory, 'runtime-mode', label: 'NullSafetyMode.sound'),
+      TestUsageEvent(NullSafetyAnalysisEvent.kNullSafetyCategory, 'stats', parameters: CustomDimensions.fromMap(<String, String>{
+        'cd49': '0', 'cd50': '1',
+      })),
+    ]));
+  });
 }
 
 class FakeGroupedValidator extends GroupedValidator {

packages/flutter_tools/test/general.shard/resident_runner_test.dart

@@ -1960,13 +1960,45 @@ flutter:
         BuildMode.debug,
         '',
         treeShakeIcons: false,
+        nullSafetyMode: NullSafetyMode.unsound,
       ),
       target: null,
       platform: FakePlatform(),
     )).generator as DefaultResidentCompiler?;
 
     expect(residentCompiler!.initializeFromDill,
-      globals.fs.path.join(getBuildDirectory(), 'cache.dill'));
+      globals.fs.path.join(getBuildDirectory(), 'fbbe6a61fb7a1de317d381f8df4814e5.cache.dill'));
+    expect(residentCompiler.librariesSpec,
+      globals.fs.file(globals.artifacts!.getHostArtifact(HostArtifact.flutterWebLibrariesJson))
+        .uri.toString());
+    expect(residentCompiler.targetModel, TargetModel.dartdevc);
+    expect(residentCompiler.sdkRoot,
+      '${globals.artifacts!.getHostArtifact(HostArtifact.flutterWebSdk).path}/');
+    expect(residentCompiler.platformDill, 'file:///HostArtifact.webPlatformKernelFolder/ddc_outline.dill');
+  }, overrides: <Type, Generator>{
+    Artifacts: () => Artifacts.test(),
+    FileSystem: () => MemoryFileSystem.test(),
+    ProcessManager: () => FakeProcessManager.any(),
+  });
+
+  testUsingContext('FlutterDevice uses dartdevc configuration when targeting web with null-safety autodetected', () async {
+    fakeVmServiceHost = FakeVmServiceHost(requests: <VmServiceExpectation>[]);
+    final FakeDevice device = FakeDevice(targetPlatform: TargetPlatform.web_javascript);
+
+    final DefaultResidentCompiler? residentCompiler = (await FlutterDevice.create(
+      device,
+      buildInfo: const BuildInfo(
+        BuildMode.debug,
+        '',
+        treeShakeIcons: false,
+        extraFrontEndOptions: <String>['--enable-experiment=non-nullable'],
+      ),
+      target: null,
+      platform: FakePlatform(),
+    )).generator as DefaultResidentCompiler?;
+
+    expect(residentCompiler!.initializeFromDill,
+      globals.fs.path.join(getBuildDirectory(), '80b1a4cf4e7b90e1ab5f72022a0bc624.cache.dill'));
     expect(residentCompiler.librariesSpec,
       globals.fs.file(globals.artifacts!.getHostArtifact(HostArtifact.flutterWebLibrariesJson))
         .uri.toString());

packages/flutter_tools/test/general.shard/runner/flutter_command_test.dart

@@ -497,6 +497,82 @@ void main() {
       ));
     });
 
+    testUsingContext('reports null safety analytics when reportNullSafety is true', () async {
+      globals.fs.file('lib/main.dart')
+        ..createSync(recursive: true)
+        ..writeAsStringSync('// @dart=2.12');
+      globals.fs.file('pubspec.yaml')
+        .writeAsStringSync('name: example\n');
+      globals.fs.file('.dart_tool/package_config.json')
+        ..createSync(recursive: true)
+        ..writeAsStringSync(r'''
+{
+  "configVersion": 2,
+  "packages": [
+    {
+      "name": "example",
+      "rootUri": "../",
+      "packageUri": "lib/",
+      "languageVersion": "2.12"
+    }
+  ],
+  "generated": "2020-12-02T19:30:53.862346Z",
+  "generator": "pub",
+  "generatorVersion": "2.12.0-76.0.dev"
+}
+''');
+      final FakeReportingNullSafetyCommand command = FakeReportingNullSafetyCommand();
+      final CommandRunner<void> runner = createTestCommandRunner(command);
+
+      await runner.run(<String>['test']);
+
+      expect(usage.events, containsAll(<TestUsageEvent>[
+        const TestUsageEvent(
+          NullSafetyAnalysisEvent.kNullSafetyCategory,
+          'runtime-mode',
+          label: 'NullSafetyMode.sound',
+        ),
+        TestUsageEvent(
+          NullSafetyAnalysisEvent.kNullSafetyCategory,
+          'stats',
+          parameters: CustomDimensions.fromMap(<String, String>{
+            'cd49': '1', 'cd50': '1',
+          }),
+        ),
+        const TestUsageEvent(
+          NullSafetyAnalysisEvent.kNullSafetyCategory,
+          'language-version',
+          label: '2.12',
+        ),
+      ]));
+    }, overrides: <Type, Generator>{
+      Pub: () => FakePub(),
+      Usage: () => usage,
+      FileSystem: () => fileSystem,
+      ProcessManager: () => processManager,
+    });
+
+    testUsingContext('tool exits on non-sound-null-safe code when explicit flag not passed', () async {
+      final DummyFlutterCommand flutterCommand = DummyFlutterCommand(packagesPath: 'foo');
+      flutterCommand.argParser
+          ..addFlag(FlutterOptions.kNullSafety, defaultsTo: true)
+          ..addOption('target');
+      final File targetFile = fileSystem.file('targetFile.dart')
+          ..writeAsStringSync('// @dart = 2.11');
+      expect(
+        () async => flutterCommand.getBuildInfo(
+          forcedBuildMode: BuildMode.debug,
+          forcedTargetFile: targetFile,
+        ),
+        throwsToolExit(
+          message: 'This application does not support sound null-safety (its language version is 2.11)',
+        ),
+      );
+    }, overrides: <Type, Generator>{
+      FileSystem: () => fileSystem,
+      ProcessManager: () => processManager,
+    });
+
     testUsingContext('use packagesPath to generate BuildInfo', () async {
       final DummyFlutterCommand flutterCommand = DummyFlutterCommand(packagesPath: 'foo');
       final BuildInfo buildInfo = await flutterCommand.getBuildInfo(forcedBuildMode: BuildMode.debug);
@@ -701,6 +777,9 @@ class FakeReportingNullSafetyCommand extends FlutterCommand {
   @override
   bool get shouldRunPub => true;
 
+  @override
+  bool get reportNullSafety => true;
+
   @override
   Future<FlutterCommandResult> runCommand() async {
     return FlutterCommandResult.success();

packages/flutter_tools/test/general.shard/test/web_test_compiler_test.dart

@@ -35,7 +35,7 @@ void main() {
         platform: platform,
     );
     final FakeProcessManager processManager = FakeProcessManager.list(<FakeCommand>[
-      const FakeCommand(command: <String>[
+      FakeCommand(command: <Pattern>[
         'Artifact.engineDartBinary.TargetPlatform.web_javascript',
         '--disable-dart-dev',
         'Artifact.frontendServerSnapshotForEngineDartSdk.TargetPlatform.web_javascript',
@@ -58,10 +58,11 @@ void main() {
         '--filesystem-scheme',
         'org-dartlang-app',
         '--initialize-from-dill',
-        r'build/cache.dill',
+        RegExp(r'^build\/(?:[a-z0-9]{32})\.cache\.dill$'),
         '--platform',
         'file:///HostArtifact.webPlatformKernelFolder/ddc_outline_sound.dill',
         '--verbosity=error',
+        '--sound-null-safety'
       ], stdout: 'result abc\nline0\nline1\nabc\nabc build/out 0')
     ]);
     final WebTestCompiler compiler = WebTestCompiler(

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

@@ -49,6 +49,7 @@ void main() {
   test('generateMainModule removes timeout from requireJS', () {
     final String result = generateMainModule(
       entrypoint: 'foo/bar/main.js',
+      nullAssertions: false,
       nativeNullAssertions: false,
     );
 
@@ -64,6 +65,7 @@ void main() {
   test('generateMainModule embeds urls correctly', () {
     final String result = generateMainModule(
       entrypoint: 'foo/bar/main.js',
+      nullAssertions: false,
       nativeNullAssertions: false,
     );
     // bootstrap main module has correct defined module.
@@ -74,6 +76,7 @@ void main() {
   test('generateMainModule can set bootstrap name', () {
     final String result = generateMainModule(
       entrypoint: 'foo/bar/main.js',
+      nullAssertions: false,
       nativeNullAssertions: false,
       bootstrapModule: 'foo_module.bootstrap',
     );
@@ -85,18 +88,22 @@ void main() {
   test('generateMainModule includes null safety switches', () {
     final String result = generateMainModule(
       entrypoint: 'foo/bar/main.js',
+      nullAssertions: true,
       nativeNullAssertions: true,
     );
 
+    expect(result, contains('''dart_sdk.dart.nonNullAsserts(true);'''));
     expect(result, contains('''dart_sdk.dart.nativeNonNullAsserts(true);'''));
   });
 
   test('generateMainModule can disable null safety switches', () {
     final String result = generateMainModule(
       entrypoint: 'foo/bar/main.js',
+      nullAssertions: false,
       nativeNullAssertions: false,
     );
 
+    expect(result, contains('''dart_sdk.dart.nonNullAsserts(false);'''));
     expect(result, contains('''dart_sdk.dart.nativeNonNullAsserts(false);'''));
   });
 

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

@@ -65,6 +65,7 @@ void main() {
         InternetAddress.loopbackIPv4,
         <String, String>{},
         <String, String>{},
+        NullSafetyMode.unsound,
       );
       releaseAssetServer = ReleaseAssetServer(
         globals.fs.file('main.dart').uri,
@@ -289,6 +290,7 @@ void main() {
       InternetAddress.loopbackIPv4,
       <String, String>{},
       <String, String>{},
+      NullSafetyMode.unsound,
     );
 
     expect(webAssetServer.basePath, 'foo/bar');
@@ -307,6 +309,7 @@ void main() {
       InternetAddress.loopbackIPv4,
       <String, String>{},
       <String, String>{},
+      NullSafetyMode.unsound,
     );
 
     // Defaults to "/" when there's no base element.
@@ -327,6 +330,7 @@ void main() {
         InternetAddress.loopbackIPv4,
         <String, String>{},
         <String, String>{},
+        NullSafetyMode.unsound,
       ),
       throwsToolExit(),
     );
@@ -346,6 +350,7 @@ void main() {
         InternetAddress.loopbackIPv4,
         <String, String>{},
         <String, String>{},
+        NullSafetyMode.unsound,
       ),
       throwsToolExit(),
     );
@@ -661,11 +666,13 @@ void main() {
       useSseForDebugProxy: true,
       useSseForDebugBackend: true,
       useSseForInjectedClient: true,
+      nullAssertions: true,
       nativeNullAssertions: true,
       buildInfo: const BuildInfo(
         BuildMode.debug,
         '',
         treeShakeIcons: false,
+        nullSafetyMode: NullSafetyMode.unsound,
       ),
       enableDwds: false,
       enableDds: false,
@@ -673,6 +680,7 @@ void main() {
       testMode: true,
       expressionCompiler: null, // ignore: avoid_redundant_argument_values
       chromiumLauncher: null, // ignore: avoid_redundant_argument_values
+      nullSafetyMode: NullSafetyMode.unsound,
     );
     webDevFS.requireJS.createSync(recursive: true);
     webDevFS.stackTraceMapper.createSync(recursive: true);
@@ -680,13 +688,13 @@ void main() {
     final Uri uri = await webDevFS.create();
     webDevFS.webAssetServer.entrypointCacheDirectory = globals.fs.currentDirectory;
     final String webPrecompiledSdk = globals.artifacts!
-      .getHostArtifact(HostArtifact.webPrecompiledSoundSdk).path;
+      .getHostArtifact(HostArtifact.webPrecompiledSdk).path;
     final String webPrecompiledSdkSourcemaps = globals.artifacts!
-      .getHostArtifact(HostArtifact.webPrecompiledSoundSdkSourcemaps).path;
+      .getHostArtifact(HostArtifact.webPrecompiledSdkSourcemaps).path;
     final String webPrecompiledCanvaskitSdk = globals.artifacts!
-      .getHostArtifact(HostArtifact.webPrecompiledCanvaskitSoundSdk).path;
+      .getHostArtifact(HostArtifact.webPrecompiledCanvaskitSdk).path;
     final String webPrecompiledCanvaskitSdkSourcemaps = globals.artifacts!
-      .getHostArtifact(HostArtifact.webPrecompiledCanvaskitSoundSdkSourcemaps).path;
+      .getHostArtifact(HostArtifact.webPrecompiledCanvaskitSdkSourcemaps).path;
     globals.fs.currentDirectory
       .childDirectory('lib')
       .childFile('web_entrypoint.dart')
@@ -771,6 +779,7 @@ void main() {
       useSseForDebugProxy: true,
       useSseForDebugBackend: true,
       useSseForInjectedClient: true,
+      nullAssertions: true,
       nativeNullAssertions: true,
       buildInfo: const BuildInfo(
         BuildMode.debug,
@@ -783,6 +792,7 @@ void main() {
       testMode: true,
       expressionCompiler: null, // ignore: avoid_redundant_argument_values
       chromiumLauncher: null, // ignore: avoid_redundant_argument_values
+      nullSafetyMode: NullSafetyMode.sound,
     );
     webDevFS.requireJS.createSync(recursive: true);
     webDevFS.stackTraceMapper.createSync(recursive: true);
@@ -878,6 +888,7 @@ void main() {
         useSseForDebugProxy: true,
         useSseForDebugBackend: true,
         useSseForInjectedClient: true,
+        nullAssertions: true,
         nativeNullAssertions: true,
         buildInfo: const BuildInfo(
           BuildMode.debug,
@@ -890,6 +901,7 @@ void main() {
         testMode: true,
         expressionCompiler: null,
         chromiumLauncher: null,
+        nullSafetyMode: NullSafetyMode.sound,
       );
       webDevFS.requireJS.createSync(recursive: true);
       webDevFS.stackTraceMapper.createSync(recursive: true);
@@ -945,7 +957,9 @@ void main() {
       testMode: true,
       expressionCompiler: null, // ignore: avoid_redundant_argument_values
       chromiumLauncher: null, // ignore: avoid_redundant_argument_values
+      nullAssertions: true,
       nativeNullAssertions: true,
+      nullSafetyMode: NullSafetyMode.sound,
     );
     webDevFS.requireJS.createSync(recursive: true);
     webDevFS.stackTraceMapper.createSync(recursive: true);
@@ -971,6 +985,7 @@ void main() {
       useSseForDebugProxy: true,
       useSseForDebugBackend: true,
       useSseForInjectedClient: true,
+      nullAssertions: true,
       nativeNullAssertions: true,
       buildInfo: const BuildInfo(
         BuildMode.debug,
@@ -986,6 +1001,7 @@ void main() {
       testMode: true,
       expressionCompiler: null, // ignore: avoid_redundant_argument_values
       chromiumLauncher: null, // ignore: avoid_redundant_argument_values
+      nullSafetyMode: NullSafetyMode.sound,
     );
     webDevFS.requireJS.createSync(recursive: true);
     webDevFS.stackTraceMapper.createSync(recursive: true);
@@ -1012,6 +1028,7 @@ void main() {
       useSseForDebugProxy: true,
       useSseForDebugBackend: true,
       useSseForInjectedClient: true,
+      nullAssertions: true,
       nativeNullAssertions: true,
       buildInfo: const BuildInfo(
         BuildMode.debug,
@@ -1027,6 +1044,7 @@ void main() {
       testMode: true,
       expressionCompiler: null, // ignore: avoid_redundant_argument_values
       chromiumLauncher: null, // ignore: avoid_redundant_argument_values
+      nullSafetyMode: NullSafetyMode.sound,
     );
     webDevFS.requireJS.createSync(recursive: true);
     webDevFS.stackTraceMapper.createSync(recursive: true);
@@ -1056,6 +1074,7 @@ void main() {
       false,
       Uri.base,
       null,
+      NullSafetyMode.unsound,
       testMode: true);
 
     expect(webAssetServer.defaultResponseHeaders['x-frame-options'], null);
@@ -1089,6 +1108,7 @@ void main() {
       InternetAddress.anyIPv4,
       <String, String>{},
       <String, String>{},
+      NullSafetyMode.sound,
     );
 
     expect(await webAssetServer.metadataContents('foo/main_module.ddc_merged_metadata'), null);
@@ -1118,6 +1138,7 @@ void main() {
       useSseForDebugProxy: true,
       useSseForDebugBackend: true,
       useSseForInjectedClient: true,
+      nullAssertions: true,
       nativeNullAssertions: true,
       buildInfo: BuildInfo.debug,
       enableDwds: false,
@@ -1126,6 +1147,7 @@ void main() {
       testMode: true,
       expressionCompiler: null, // ignore: avoid_redundant_argument_values
       chromiumLauncher: null, // ignore: avoid_redundant_argument_values
+      nullSafetyMode: NullSafetyMode.unsound,
     );
     webDevFS.requireJS.createSync(recursive: true);
     webDevFS.stackTraceMapper.createSync(recursive: true);

packages/flutter_tools/test/general.shard/web/migrations/scrub_generated_plugin_registrant_test.dart

@@ -4,6 +4,7 @@
 
 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/build_system/build_system.dart';
 import 'package:flutter_tools/src/cache.dart';
 import 'package:flutter_tools/src/commands/build.dart';
@@ -49,6 +50,7 @@ void main() {
         androidSdk: FakeAndroidSdk(),
         buildSystem: buildSystem,
         fileSystem: fileSystem,
+        logger: BufferLogger.test(),
         osUtils: FakeOperatingSystemUtils(),
       ))
           .run(<String>['build', 'web', '--no-pub']);
@@ -71,6 +73,7 @@ void main() {
         androidSdk: FakeAndroidSdk(),
         buildSystem: buildSystem,
         fileSystem: fileSystem,
+        logger: BufferLogger.test(),
         osUtils: FakeOperatingSystemUtils(),
       ))
           .run(<String>['build', 'web', '--no-pub']);
@@ -92,6 +95,7 @@ void main() {
         androidSdk: FakeAndroidSdk(),
         buildSystem: buildSystem,
         fileSystem: fileSystem,
+        logger: BufferLogger.test(),
         osUtils: FakeOperatingSystemUtils(),
       ))
           .run(<String>['build', 'web', '--no-pub']);
@@ -112,6 +116,7 @@ void main() {
         androidSdk: FakeAndroidSdk(),
         buildSystem: buildSystem,
         fileSystem: fileSystem,
+        logger: BufferLogger.test(),
         osUtils: FakeOperatingSystemUtils(),
       ))
           .run(<String>['build', 'web', '--no-pub']);
@@ -134,6 +139,7 @@ void main() {
         androidSdk: FakeAndroidSdk(),
         buildSystem: buildSystem,
         fileSystem: fileSystem,
+        logger: BufferLogger.test(),
         osUtils: FakeOperatingSystemUtils(),
       ))
           .run(<String>['build', 'web', '--no-pub']);

packages/flutter_tools/test/integration.shard/flutter_build_null_unsafe_test.dart

@@ -0,0 +1,83 @@
+// Copyright 2014 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'package:file/file.dart';
+import 'package:flutter_tools/src/base/io.dart';
+
+import '../src/common.dart';
+import 'test_utils.dart';
+
+void main() {
+  late Directory tempDir;
+  late Directory projectRoot;
+  late String flutterBin;
+  final List<String> targetPlatforms = <String>[
+    'apk',
+    'web',
+    if (platform.isWindows) 'windows',
+    if (platform.isMacOS) ...<String>['macos', 'ios'],
+  ];
+
+  setUpAll(() {
+    tempDir = createResolvedTempDirectorySync('build_null_unsafe_test.');
+    flutterBin = fileSystem.path.join(
+      getFlutterRoot(),
+      'bin',
+      'flutter',
+    );
+    processManager.runSync(<String>[
+      flutterBin,
+      'config',
+      '--enable-macos-desktop',
+      '--enable-windows-desktop',
+      '--enable-web',
+    ]);
+
+    processManager.runSync(<String>[
+      flutterBin,
+      ...getLocalEngineArguments(),
+      'create',
+      'hello',
+    ], workingDirectory: tempDir.path);
+
+    projectRoot = tempDir.childDirectory('hello');
+    writeFile(fileSystem.path.join(projectRoot.path, 'pubspec.yaml'), '''
+name: hello
+environment:
+  sdk: '>=2.12.0 <4.0.0'
+''');
+    writeFile(fileSystem.path.join(projectRoot.path, 'lib', 'main.dart'), '''
+import 'unsafe.dart';
+void main() {
+  print(unsafeString);
+}
+''');
+    writeFile(fileSystem.path.join(projectRoot.path, 'lib', 'unsafe.dart'), '''
+// @dart=2.9
+String unsafeString = null;
+''');
+  });
+
+  tearDownAll(() {
+    tryToDelete(tempDir);
+  });
+
+  for (final String targetPlatform in targetPlatforms) {
+    testWithoutContext('flutter build $targetPlatform --no-sound-null-safety', () {
+      final ProcessResult result = processManager.runSync(<String>[
+        flutterBin,
+        ...getLocalEngineArguments(),
+        'build',
+        targetPlatform,
+        '--no-pub',
+        '--no-sound-null-safety',
+        if (targetPlatform == 'ios') '--no-codesign',
+      ], workingDirectory: projectRoot.path);
+
+      if (result.exitCode != 0) {
+        fail('build --no-sound-null-safety failed: ${result.exitCode}\n${result.stderr}\n${result.stdout}');
+      }
+    });
+  }
+}