[flutter_tools] add flag for sound-null-safety, unify with experiments (#58533)

Also combines experiments into extraGenSnapshot/ExtraFrontEndOptions. Allows providing --no-sound-null-safety to allow out of order migration and running.
2020-06-03 21:02:07 -07:00 · 2020-06-03 21:02:07 -07:00 · b1d75fc99d
commit b1d75fc99d
parent 95edf28150
38 changed files with 127 additions and 114 deletions
--- a/dev/bots/test.dart
+++ b/dev/bots/test.dart
@ -340,8 +340,7 @@ Future<void> _runToolTests() async {
 /// target app.
 Future<void> _runBuildTests() async {
  final List<FileSystemEntity> exampleDirectories = Directory(path.join(flutterRoot, 'examples')).listSync()
-    // TODO(jonahwilliams): re-enable once https://github.com/flutter/flutter/issues/57234 is done.
-    // ..add(Directory(path.join(flutterRoot, 'dev', 'integration_tests', 'non_nullable')))
+    ..add(Directory(path.join(flutterRoot, 'dev', 'integration_tests', 'non_nullable')))
    ..add(Directory(path.join(flutterRoot, 'dev', 'integration_tests', 'flutter_gallery')));

  final String branch = Platform.environment['CIRRUS_BRANCH'];
@ -377,7 +376,7 @@ Future<void> _runExampleProjectBuildTests(FileSystemEntity exampleDirectory) asy
  final String examplePath = exampleDirectory.path;
  final bool hasNullSafety = File(path.join(examplePath, 'null_safety')).existsSync();
  final List<String> additionalArgs = hasNullSafety
-    ? <String>['--enable-experiment', 'non-nullable']
+    ? <String>['--enable-experiment', 'non-nullable', '--no-sound-null-safety']
    : <String>[];
  if (Directory(path.join(examplePath, 'android')).existsSync()) {
    await _flutterBuildApk(examplePath, release: false, additionalArgs: additionalArgs, verifyCaching: verifyCaching);
@ -603,10 +602,9 @@ Future<void> _runFrameworkTests() async {
    await _runFlutterTest(path.join(flutterRoot, 'packages', 'flutter_localizations'), tableData: bigqueryApi?.tabledata);
    await _runFlutterTest(path.join(flutterRoot, 'packages', 'flutter_test'), tableData: bigqueryApi?.tabledata);
    await _runFlutterTest(path.join(flutterRoot, 'packages', 'fuchsia_remote_debug_protocol'), tableData: bigqueryApi?.tabledata);
-    // TODO(jonahwilliams): re-enable once https://github.com/flutter/flutter/issues/57234 is done.
-    // await _runFlutterTest(path.join(flutterRoot, 'dev', 'integration_tests', 'non_nullable'),
-    //   options: <String>['--enable-experiment=non-nullable'],
-    // );
+    await _runFlutterTest(path.join(flutterRoot, 'dev', 'integration_tests', 'non_nullable'),
+      options: <String>['--enable-experiment=non-nullable', '--no-sound-null-safety'],
+    );
    await _runFlutterTest(
      path.join(flutterRoot, 'dev', 'tracing_tests'),
      options: <String>['--enable-vmservice'],
@ -756,8 +754,7 @@ Future<void> _runWebIntegrationTests() async {
  await _runWebDebugTest('lib/stack_trace.dart');
  await _runWebDebugTest('lib/web_directory_loading.dart');
  await _runWebDebugTest('test/test.dart');
-  // TODO(jonahwilliams): re-enable once https://github.com/flutter/flutter/issues/57234 is done.
-  // await _runWebDebugTest('lib/null_safe_main.dart', enableNullSafety: true);
+  await _runWebDebugTest('lib/null_safe_main.dart', enableNullSafety: true);
  await _runWebDebugTest('lib/web_define_loading.dart',
    additionalArguments: <String>[
      '--dart-define=test.valueA=Example',
@ -875,6 +872,7 @@ Future<void> _runWebDebugTest(String target, {
        ...<String>[
          '--enable-experiment',
          'non-nullable',
+          '--no-sound-null-safety'
        ],
      '-d',
      'chrome',
--- a/packages/flutter_tools/bin/fuchsia_tester.dart
+++ b/packages/flutter_tools/bin/fuchsia_tester.dart
@ -155,7 +155,7 @@ Future<void> run(List<String> args) async {
      concurrency: math.max(1, globals.platform.numberOfProcessors - 2),
      icudtlPath: globals.fs.path.absolute(argResults[_kOptionIcudtl] as String),
      coverageDirectory: coverageDirectory,
-      dartExperiments: <String>[],
+      extraFrontEndOptions: <String>[],
    );

    if (collector != null) {
--- a/packages/flutter_tools/bin/macos_assemble.sh
+++ b/packages/flutter_tools/bin/macos_assemble.sh
@ -82,7 +82,7 @@ RunCommand "${FLUTTER_ROOT}/bin/flutter"                                    \
    -dTrackWidgetCreation="${TRACK_WIDGET_CREATION}"                        \
    --DartDefines="${DART_DEFINES}"                                         \
    --ExtraGenSnapshotOptions="${EXTRA_GEN_SNAPSHOT_OPTIONS}"               \
-    -dExtraFrontEndOptions="${EXTRA_FRONT_END_OPTIONS}"                     \
+    --ExtraFrontEndOptions="${EXTRA_FRONT_END_OPTIONS}"                     \
    --build-inputs="${build_inputs_path}"                                   \
    --build-outputs="${build_outputs_path}"                                 \
    --output="${ephemeral_dir}"                                             \
--- a/packages/flutter_tools/bin/tool_backend.dart
+++ b/packages/flutter_tools/bin/tool_backend.dart
@ -69,7 +69,7 @@ or
      if (extraGenSnapshotOptions != null)
        '--ExtraGenSnapshotOptions=$extraGenSnapshotOptions',
      if (extraFrontEndOptions != null)
-        '-dExtraFrontEndOptions=$extraFrontEndOptions',
+        '--ExtraFrontEndOptions=$extraFrontEndOptions',
      target,
    ],
  );
--- a/packages/flutter_tools/bin/xcode_backend.sh
+++ b/packages/flutter_tools/bin/xcode_backend.sh
@ -168,7 +168,7 @@ is set to release or run \"flutter build ios --release\", then re-run Archive fr
    -dEnableBitcode="${bitcode_flag}"                                     \
    --ExtraGenSnapshotOptions="${EXTRA_GEN_SNAPSHOT_OPTIONS}"             \
    --DartDefines="${DART_DEFINES}"                                       \
-    -dExtraFrontEndOptions="${EXTRA_FRONT_END_OPTIONS}"                   \
+    --ExtraFrontEndOptions="${EXTRA_FRONT_END_OPTIONS}"                   \
    "${build_mode}_ios_bundle_flutter_assets"

  if [[ $? -ne 0 ]]; then
--- a/packages/flutter_tools/gradle/flutter.gradle
+++ b/packages/flutter_tools/gradle/flutter.gradle
@ -919,9 +919,6 @@ abstract class BaseFlutterTask extends DefaultTask {
            }
            args "-dTargetPlatform=android"
            args "-dBuildMode=${buildMode}"
-            if (extraFrontEndOptions != null) {
-                args "-dExtraFrontEndOptions=${extraFrontEndOptions}"
-            }
            if (trackWidgetCreation != null) {
                args "-dTrackWidgetCreation=${trackWidgetCreation}"
            }
@ -943,6 +940,9 @@ abstract class BaseFlutterTask extends DefaultTask {
            if (extraGenSnapshotOptions != null) {
                args "--ExtraGenSnapshotOptions=${extraGenSnapshotOptions}"
            }
+            if (extraFrontEndOptions != null) {
+                args "--ExtraFrontEndOptions=${extraFrontEndOptions}"
+            }
            args ruleNames
        }
    }
--- a/packages/flutter_tools/lib/src/android/gradle.dart
+++ b/packages/flutter_tools/lib/src/android/gradle.dart
@ -310,10 +310,10 @@ Future<void> buildGradleApp({
  command.add('-Ptrack-widget-creation=${buildInfo.trackWidgetCreation}');

  if (buildInfo.extraFrontEndOptions != null) {
-    command.add('-Pextra-front-end-options=${buildInfo.extraFrontEndOptions.join(',')}');
+    command.add('-Pextra-front-end-options=${encodeDartDefines(buildInfo.extraFrontEndOptions)}');
  }
  if (buildInfo.extraGenSnapshotOptions != null) {
-    command.add('-Pextra-gen-snapshot-options=${buildInfo.extraGenSnapshotOptions.join(',')}');
+    command.add('-Pextra-gen-snapshot-options=${encodeDartDefines(buildInfo.extraGenSnapshotOptions)}');
  }
  if (buildInfo.fileSystemRoots != null && buildInfo.fileSystemRoots.isNotEmpty) {
    command.add('-Pfilesystem-roots=${buildInfo.fileSystemRoots.join('|')}');
--- a/packages/flutter_tools/lib/src/build_info.dart
+++ b/packages/flutter_tools/lib/src/build_info.dart
@ -143,9 +143,9 @@ class BuildInfo {
      if (dartObfuscation != null)
        'DART_OBFUSCATION': dartObfuscation.toString(),
      if (extraFrontEndOptions?.isNotEmpty ?? false)
-        'EXTRA_FRONT_END_OPTIONS': extraFrontEndOptions.join(','),
+        'EXTRA_FRONT_END_OPTIONS': encodeDartDefines(extraFrontEndOptions),
      if (extraGenSnapshotOptions?.isNotEmpty ?? false)
-        'EXTRA_GEN_SNAPSHOT_OPTIONS': extraGenSnapshotOptions.join(','),
+        'EXTRA_GEN_SNAPSHOT_OPTIONS': encodeDartDefines(extraGenSnapshotOptions),
      if (splitDebugInfoPath != null)
        'SPLIT_DEBUG_INFO': splitDebugInfoPath,
      if (trackWidgetCreation != null)
@ -667,11 +667,11 @@ String encodeDartDefines(List<String> defines) {
 }

 /// Dart defines are encoded inside [environmentDefines] as a comma-separated list.
-List<String> decodeDartDefines(Map<String, String> environmentDefines) {
-  if (!environmentDefines.containsKey(kDartDefines) || environmentDefines[kDartDefines].isEmpty) {
+List<String> decodeDartDefines(Map<String, String> environmentDefines, String key) {
+  if (!environmentDefines.containsKey(key) || environmentDefines[key].isEmpty) {
    return const <String>[];
  }
-  return environmentDefines[kDartDefines]
+  return environmentDefines[key]
    .split(',')
    .map<Object>(Uri.decodeComponent)
    .cast<String>()
--- a/packages/flutter_tools/lib/src/build_runner/resident_web_runner.dart
+++ b/packages/flutter_tools/lib/src/build_runner/resident_web_runner.dart
@ -441,7 +441,6 @@ class _ResidentWebRunner extends ResidentWebRunner {
            debuggingOptions.buildInfo,
            debuggingOptions.initializePlatform,
            false,
-            debuggingOptions.buildInfo.dartExperiments,
          );
        }
        await device.device.startApp(
@ -504,7 +503,6 @@ class _ResidentWebRunner extends ResidentWebRunner {
          debuggingOptions.buildInfo,
          debuggingOptions.initializePlatform,
          false,
-          debuggingOptions.buildInfo.dartExperiments,
        );
      } on ToolExit {
        return OperationResult(1, 'Failed to recompile application.');
--- a/packages/flutter_tools/lib/src/build_system/targets/android.dart
+++ b/packages/flutter_tools/lib/src/build_system/targets/android.dart
@ -246,8 +246,7 @@ class AndroidAot extends AotElfBase {
    if (!output.existsSync()) {
      output.createSync(recursive: true);
    }
-    final List<String> extraGenSnapshotOptions = environment.defines[kExtraGenSnapshotOptions]?.split(',')
-      ?? const <String>[];
+    final List<String> extraGenSnapshotOptions = decodeDartDefines(environment.defines, kExtraGenSnapshotOptions);
    final BuildMode buildMode = getBuildModeForName(environment.defines[kBuildMode]);
    final bool dartObfuscation = environment.defines[kDartObfuscation] == 'true';
    final int snapshotExitCode = await snapshotter.build(
--- a/packages/flutter_tools/lib/src/build_system/targets/dart.dart
+++ b/packages/flutter_tools/lib/src/build_system/targets/dart.dart
@ -205,10 +205,7 @@ class KernelSnapshot extends Target {
    final TargetPlatform targetPlatform = getTargetPlatformForName(environment.defines[kTargetPlatform]);

    // This configuration is all optional.
-    final String rawFrontEndOption = environment.defines[kExtraFrontEndOptions];
-    final List<String> extraFrontEndOptions = (rawFrontEndOption?.isNotEmpty ?? false)
-      ? rawFrontEndOption?.split(',')
-      : null;
+    final List<String> extraFrontEndOptions = decodeDartDefines(environment.defines, kExtraFrontEndOptions);
    final List<String> fileSystemRoots = environment.defines[kFileSystemRoots]?.split(',');
    final String fileSystemScheme = environment.defines[kFileSystemScheme];

@ -254,7 +251,7 @@ class KernelSnapshot extends Target {
      extraFrontEndOptions: extraFrontEndOptions,
      fileSystemRoots: fileSystemRoots,
      fileSystemScheme: fileSystemScheme,
-      dartDefines: decodeDartDefines(environment.defines),
+      dartDefines: decodeDartDefines(environment.defines, kDartDefines),
      packageConfig: packageConfig,
    );
    if (output == null || output.errorCount != 0) {
@ -287,8 +284,7 @@ abstract class AotElfBase extends Target {
    if (environment.defines[kTargetPlatform] == null) {
      throw MissingDefineException(kTargetPlatform, 'aot_elf');
    }
-    final List<String> extraGenSnapshotOptions = environment.defines[kExtraGenSnapshotOptions]?.split(',')
-      ?? const <String>[];
+    final List<String> extraGenSnapshotOptions = decodeDartDefines(environment.defines, kExtraGenSnapshotOptions);
    final BuildMode buildMode = getBuildModeForName(environment.defines[kBuildMode]);
    final TargetPlatform targetPlatform = getTargetPlatformForName(environment.defines[kTargetPlatform]);
    final String splitDebugInfo = environment.defines[kSplitDebugInfo];
--- a/packages/flutter_tools/lib/src/build_system/targets/ios.dart
+++ b/packages/flutter_tools/lib/src/build_system/targets/ios.dart
@ -46,7 +46,7 @@ abstract class AotAssemblyBase extends Target {
    if (environment.defines[kTargetPlatform] == null) {
      throw MissingDefineException(kTargetPlatform, 'aot_assembly');
    }
-    final List<String> extraGenSnapshotOptions = parseExtraGenSnapshotOptions(environment);
+    final List<String> extraGenSnapshotOptions = decodeDartDefines(environment.defines, kExtraGenSnapshotOptions);
    final bool bitcode = environment.defines[kBitcodeFlag] == 'true';
    final BuildMode buildMode = getBuildModeForName(environment.defines[kBuildMode]);
    final TargetPlatform targetPlatform = getTargetPlatformForName(environment.defines[kTargetPlatform]);
@ -447,13 +447,3 @@ Future<RunResult> createStubAppFramework(File outputFile, SdkType sdk, { bool in
    }
  }
 }
-
-/// iOS and macOS build scripts may pass extraGenSnapshotOptions as an empty
-/// string.
-List<String> parseExtraGenSnapshotOptions(Environment environment) {
-  final String value = environment.defines[kExtraGenSnapshotOptions];
-  if (value == null || value.trim().isEmpty) {
-    return <String>[];
-  }
-  return value.split(',');
-}
--- a/packages/flutter_tools/lib/src/build_system/targets/macos.dart
+++ b/packages/flutter_tools/lib/src/build_system/targets/macos.dart
@ -15,7 +15,6 @@ import '../exceptions.dart';
 import 'assets.dart';
 import 'dart.dart';
 import 'icon_tree_shaker.dart';
-import 'ios.dart';

 /// Copy the macOS framework to the correct copy dir by invoking 'cp -R'.
 ///
@ -198,7 +197,7 @@ class CompileMacOSFramework extends Target {
    }
    final String splitDebugInfo = environment.defines[kSplitDebugInfo];
    final bool dartObfuscation = environment.defines[kDartObfuscation] == 'true';
-    final List<String> extraGenSnapshotOptions = parseExtraGenSnapshotOptions(environment);
+    final List<String> extraGenSnapshotOptions = decodeDartDefines(environment.defines, kExtraGenSnapshotOptions);
    final AOTSnapshotter snapshotter = AOTSnapshotter(
      reportTimings: false,
      fileSystem: globals.fs,
--- a/packages/flutter_tools/lib/src/build_system/targets/web.dart
+++ b/packages/flutter_tools/lib/src/build_system/targets/web.dart
@ -28,11 +28,6 @@ const String kHasWebPlugins = 'HasWebPlugins';
 /// Valid values are O1 (lowest, profile default) to O4 (highest, release default).
 const String kDart2jsOptimization = 'Dart2jsOptimization';

-/// Allow specifying experiments for dart2js.
-///
-/// Multiple values should be encoded as a comma-separated list.
-const String kEnableExperiment = 'EnableExperiment';
-
 /// Whether to disable dynamic generation code to satisfy csp policies.
 const String kCspMode = 'cspMode';

@ -164,8 +159,8 @@ class Dart2JSTarget extends Target {
    final String packageFile = globalPackagesPath;
    final File outputKernel = environment.buildDir.childFile('app.dill');
    final File outputFile = environment.buildDir.childFile('main.dart.js');
-    final List<String> dartDefines = decodeDartDefines(environment.defines);
-    final String enabledExperiments = environment.defines[kEnableExperiment];
+    final List<String> dartDefines = decodeDartDefines(environment.defines, kDartDefines);
+    final List<String> extraFrontEndOptions = decodeDartDefines(environment.defines, kExtraFrontEndOptions);

    // Run the dart2js compilation in two stages, so that icon tree shaking can
    // parse the kernel file for web builds.
@ -173,8 +168,7 @@ class Dart2JSTarget extends Target {
      globals.artifacts.getArtifactPath(Artifact.engineDartBinary),
      globals.artifacts.getArtifactPath(Artifact.dart2jsSnapshot),
      '--libraries-spec=$specPath',
-      if (enabledExperiments != null)
-        '--enable-experiment=$enabledExperiments',
+      ...?extraFrontEndOptions,
      '-o',
      outputKernel.path,
      '--packages=$packageFile',
@ -194,8 +188,7 @@ class Dart2JSTarget extends Target {
      globals.artifacts.getArtifactPath(Artifact.engineDartBinary),
      globals.artifacts.getArtifactPath(Artifact.dart2jsSnapshot),
      '--libraries-spec=$specPath',
-      if (enabledExperiments != null)
-        '--enable-experiment=$enabledExperiments',
+      ...?extraFrontEndOptions,
      if (dart2jsOptimization != null)
        '-$dart2jsOptimization'
      else
--- a/packages/flutter_tools/lib/src/commands/assemble.dart
+++ b/packages/flutter_tools/lib/src/commands/assemble.dart
@ -105,6 +105,7 @@ class AssembleCommand extends FlutterCommand {
        'root of the current Flutter project.',
    );
    argParser.addOption(kExtraGenSnapshotOptions);
+    argParser.addOption(kExtraFrontEndOptions);
    argParser.addOption(kDartDefines);
    argParser.addOption(
      'resource-pool-size',
@ -204,10 +205,12 @@ class AssembleCommand extends FlutterCommand {
    if (argResults.wasParsed(kExtraGenSnapshotOptions)) {
      results[kExtraGenSnapshotOptions] = argResults[kExtraGenSnapshotOptions] as String;
    }
-    // Workaround for dart-define formatting
    if (argResults.wasParsed(kDartDefines)) {
      results[kDartDefines] = argResults[kDartDefines] as String;
    }
+    if (argResults.wasParsed(kExtraFrontEndOptions)) {
+      results[kExtraFrontEndOptions] = argResults[kExtraFrontEndOptions] as String;
+    }
    return results;
  }

--- a/packages/flutter_tools/lib/src/commands/build_aar.dart
+++ b/packages/flutter_tools/lib/src/commands/build_aar.dart
@ -41,6 +41,7 @@ class BuildAarCommand extends BuildSubCommand {
    addSplitDebugInfoOption();
    addDartObfuscationOption();
    usesTrackWidgetCreation(verboseHelp: false);
+    addNullSafetyModeOptions();
    argParser
      ..addMultiOption(
        'target-platform',
--- a/packages/flutter_tools/lib/src/commands/build_apk.dart
+++ b/packages/flutter_tools/lib/src/commands/build_apk.dart
@ -33,6 +33,7 @@ class BuildApkCommand extends BuildSubCommand {
    addBundleSkSLPathOption(hide: !verboseHelp);
    addEnableExperimentation(hide: !verboseHelp);
    addBuildPerformanceFile(hide: !verboseHelp);
+    addNullSafetyModeOptions();
    argParser
      ..addFlag('split-per-abi',
        negatable: false,
--- a/packages/flutter_tools/lib/src/commands/build_fuchsia.dart
+++ b/packages/flutter_tools/lib/src/commands/build_fuchsia.dart
@ -21,6 +21,7 @@ class BuildFuchsiaCommand extends BuildSubCommand {
    usesTargetOption();
    usesDartDefineOption();
    addBuildModeFlags(verboseHelp: verboseHelp);
+    addNullSafetyModeOptions();
    argParser.addOption(
      'runner-source',
      help: 'The package source to use for the flutter_runner. '
--- a/packages/flutter_tools/lib/src/commands/build_ios.dart
+++ b/packages/flutter_tools/lib/src/commands/build_ios.dart
@ -33,6 +33,7 @@ class BuildIOSCommand extends BuildSubCommand {
    usesExtraFrontendOptions();
    addEnableExperimentation(hide: !verboseHelp);
    addBuildPerformanceFile(hide: !verboseHelp);
+    addNullSafetyModeOptions();
    argParser
      ..addFlag('simulator',
        help: 'Build for the iOS simulator instead of the device. This changes '
--- a/packages/flutter_tools/lib/src/commands/build_linux.dart
+++ b/packages/flutter_tools/lib/src/commands/build_linux.dart
@ -28,6 +28,7 @@ class BuildLinuxCommand extends BuildSubCommand {
    addEnableExperimentation(hide: !verboseHelp);
    usesTrackWidgetCreation(verboseHelp: verboseHelp);
    addBuildPerformanceFile(hide: !verboseHelp);
+    addNullSafetyModeOptions();
  }

  @override
--- a/packages/flutter_tools/lib/src/commands/build_macos.dart
+++ b/packages/flutter_tools/lib/src/commands/build_macos.dart
@ -29,6 +29,7 @@ class BuildMacosCommand extends BuildSubCommand {
    usesBuildNameOption();
    addEnableExperimentation(hide: !verboseHelp);
    addBuildPerformanceFile(hide: !verboseHelp);
+    addNullSafetyModeOptions();
  }

  @override
--- a/packages/flutter_tools/lib/src/commands/build_web.dart
+++ b/packages/flutter_tools/lib/src/commands/build_web.dart
@ -11,7 +11,7 @@ import '../build_info.dart';
 import '../features.dart';
 import '../project.dart';
 import '../runner/flutter_command.dart'
-    show DevelopmentArtifact, FlutterCommandResult, FlutterOptions;
+    show DevelopmentArtifact, FlutterCommandResult;
 import '../web/compile.dart';
 import 'build.dart';

@ -25,6 +25,7 @@ class BuildWebCommand extends BuildSubCommand {
    addBuildModeFlags(excludeDebug: true);
    usesDartDefineOption();
    addEnableExperimentation(hide: !verboseHelp);
+    addNullSafetyModeOptions();
    argParser.addFlag('web-initialize-platform',
        defaultsTo: true,
        negatable: true,
@ -71,7 +72,6 @@ class BuildWebCommand extends BuildSubCommand {
      buildInfo,
      boolArg('web-initialize-platform'),
      boolArg('csp'),
-      stringsArg(FlutterOptions.kEnableExperiment),
    );
    return FlutterCommandResult.success();
  }
--- a/packages/flutter_tools/lib/src/commands/run.dart
+++ b/packages/flutter_tools/lib/src/commands/run.dart
@ -66,6 +66,7 @@ abstract class RunCommandBase extends FlutterCommand with DeviceBasedDevelopment
    usesPubOption();
    usesTrackWidgetCreation(verboseHelp: verboseHelp);
    usesIsolateFilterOption(hide: !verboseHelp);
+    addNullSafetyModeOptions();
  }

  bool get traceStartup => boolArg('trace-startup');
--- a/packages/flutter_tools/lib/src/commands/test.dart
+++ b/packages/flutter_tools/lib/src/commands/test.dart
@ -31,6 +31,9 @@ class TestCommand extends FlutterCommand {
  }) : assert(testWrapper != null) {
    requiresPubspecYaml();
    usesPubOption();
+    addNullSafetyModeOptions();
+    usesTrackWidgetCreation(verboseHelp: verboseHelp);
+    addEnableExperimentation(hide: !verboseHelp);
    argParser
      ..addMultiOption('name',
        help: 'A regular expression matching substrings of the names of tests to run.',
@ -128,8 +131,6 @@ class TestCommand extends FlutterCommand {
              'This flag is ignored if --start-paused or coverage are requested. '
              'The vmservice will be enabled no matter what in those cases.'
      );
-    usesTrackWidgetCreation(verboseHelp: verboseHelp);
-    addEnableExperimentation(hide: !verboseHelp);
  }

  /// The interface for starting and configuring the tester.
@ -172,7 +173,6 @@ class TestCommand extends FlutterCommand {
    final String tags = stringArg('tags');
    final String excludeTags = stringArg('exclude-tags');
    final FlutterProject flutterProject = FlutterProject.current();
-    final List<String> dartExperiments = stringsArg(FlutterOptions.kEnableExperiment);

    if (buildTestAssets && flutterProject.manifest.assets.isNotEmpty) {
      await _buildTestAsset();
@ -278,7 +278,7 @@ class TestCommand extends FlutterCommand {
      flutterProject: flutterProject,
      web: stringArg('platform') == 'chrome',
      randomSeed: stringArg('test-randomize-ordering-seed'),
-      dartExperiments: dartExperiments,
+      extraFrontEndOptions: getBuildInfo(forcedBuildMode: BuildMode.debug).extraFrontEndOptions,
    );

    if (collector != null) {
--- a/packages/flutter_tools/lib/src/compile.dart
+++ b/packages/flutter_tools/lib/src/compile.dart
@ -269,7 +269,14 @@ class KernelCompiler {
        '--platform',
        platformDill,
      ],
-      ...?extraFrontEndOptions,
+      if (extraFrontEndOptions != null)
+        for (String arg in extraFrontEndOptions)
+          if (arg == '--sound-null-safety')
+            '--null-safety'
+          else if (arg == '--no-sound-null-safety')
+            '--no-null-safety'
+          else
+            arg,
      mainUri?.toString() ?? mainPath,
    ];

@ -398,7 +405,7 @@ abstract class ResidentCompiler {
    String initializeFromDill,
    TargetModel targetModel,
    bool unsafePackageSerialization,
-    List<String> experimentalFlags,
+    List<String> extraFrontEndOptions,
    String platformDill,
    List<String> dartDefines,
    String librariesSpec,
@ -494,7 +501,7 @@ class DefaultResidentCompiler implements ResidentCompiler {
    this.initializeFromDill,
    this.targetModel = TargetModel.flutter,
    this.unsafePackageSerialization,
-    this.experimentalFlags,
+    this.extraFrontEndOptions,
    this.platformDill,
    List<String> dartDefines,
    this.librariesSpec,
@ -512,7 +519,7 @@ class DefaultResidentCompiler implements ResidentCompiler {
  final String fileSystemScheme;
  final String initializeFromDill;
  final bool unsafePackageSerialization;
-  final List<String> experimentalFlags;
+  final List<String> extraFrontEndOptions;
  final List<String> dartDefines;
  final String librariesSpec;

@ -660,8 +667,14 @@ class DefaultResidentCompiler implements ResidentCompiler {
        platformDill,
      ],
      if (unsafePackageSerialization == true) '--unsafe-package-serialization',
-      if ((experimentalFlags != null) && experimentalFlags.isNotEmpty)
-        '--enable-experiment=${experimentalFlags.join(',')}',
+      if (extraFrontEndOptions != null)
+        for (String arg in extraFrontEndOptions)
+          if (arg == '--sound-null-safety')
+            '--null-safety'
+          else if (arg == '--no-sound-null-safety')
+            '--no-null-safety'
+          else
+            arg,
    ];
    globals.printTrace(command.join(' '));
    _server = await globals.processManager.start(command);
--- a/packages/flutter_tools/lib/src/resident_runner.dart
+++ b/packages/flutter_tools/lib/src/resident_runner.dart
@ -47,7 +47,6 @@ class FlutterDevice {
    this.viewFilter,
    TargetModel targetModel = TargetModel.flutter,
    TargetPlatform targetPlatform,
-    List<String> experimentalFlags,
    ResidentCompiler generator,
  }) : assert(buildInfo.trackWidgetCreation != null),
       generator = generator ?? ResidentCompiler(
@ -61,9 +60,9 @@ class FlutterDevice {
         fileSystemRoots: fileSystemRoots ?? <String>[],
         fileSystemScheme: fileSystemScheme,
         targetModel: targetModel,
-         experimentalFlags: experimentalFlags,
         dartDefines: buildInfo.dartDefines,
         packagesPath: globalPackagesPath,
+         extraFrontEndOptions: buildInfo.extraFrontEndOptions,
       );

  /// Create a [FlutterDevice] with optional code generation enabled.
@ -106,7 +105,7 @@ class FlutterDevice {
          trackWidgetCreation: buildInfo.trackWidgetCreation,
        ),
        targetModel: TargetModel.dartdevc,
-        experimentalFlags: experimentalFlags,
+        extraFrontEndOptions: buildInfo.extraFrontEndOptions,
        platformDill: globals.fs.file(globals.artifacts
          .getArtifactPath(Artifact.webPlatformKernelDill, mode: buildInfo.mode))
          .absolute.uri.toString(),
@ -127,8 +126,8 @@ class FlutterDevice {
        fileSystemRoots: fileSystemRoots,
        fileSystemScheme: fileSystemScheme,
        targetModel: targetModel,
-        experimentalFlags: experimentalFlags,
        dartDefines: buildInfo.dartDefines,
+        extraFrontEndOptions: buildInfo.extraFrontEndOptions,
        initializeFromDill: getDefaultCachedKernelPath(
          trackWidgetCreation: buildInfo.trackWidgetCreation,
        ),
@ -148,7 +147,6 @@ class FlutterDevice {
      fileSystemRoots: fileSystemRoots,
      fileSystemScheme:fileSystemScheme,
      viewFilter: viewFilter,
-      experimentalFlags: experimentalFlags,
      targetModel: targetModel,
      targetPlatform: targetPlatform,
      generator: generator,
--- a/packages/flutter_tools/lib/src/runner/flutter_command.dart
+++ b/packages/flutter_tools/lib/src/runner/flutter_command.dart
@ -109,6 +109,7 @@ class FlutterOptions {
  static const String kDartDefinesOption = 'dart-define';
  static const String kBundleSkSLPathOption = 'bundle-sksl-path';
  static const String kPerformanceMeasurementFile = 'performance-measurement-file';
+  static const String kNullSafety = 'sound-null-safety';
 }

 abstract class FlutterCommand extends Command<void> {
@ -460,6 +461,14 @@ abstract class FlutterCommand extends Command<void> {
      );
  }

+  void addNullSafetyModeOptions() {
+    argParser.addFlag(FlutterOptions.kNullSafety,
+      help: 'Whether to override the default null safety setting.',
+      defaultsTo: null,
+      hide: true,
+    );
+  }
+
  void usesExtraFrontendOptions() {
    argParser.addMultiOption(FlutterOptions.kExtraFrontEndOptions,
      splitCommas: true,
@ -572,15 +581,15 @@ abstract class FlutterCommand extends Command<void> {

    final List<String> experiments =
      argParser.options.containsKey(FlutterOptions.kEnableExperiment)
-        ? stringsArg(FlutterOptions.kEnableExperiment)
+        ? stringsArg(FlutterOptions.kEnableExperiment).toList()
        : <String>[];
    final List<String> extraGenSnapshotOptions =
      argParser.options.containsKey(FlutterOptions.kExtraGenSnapshotOptions)
-        ? stringsArg(FlutterOptions.kExtraGenSnapshotOptions)
+        ? stringsArg(FlutterOptions.kExtraGenSnapshotOptions).toList()
        : <String>[];
    final List<String> extraFrontEndOptions =
      argParser.options.containsKey(FlutterOptions.kExtraFrontEndOptions)
-          ? stringsArg(FlutterOptions.kExtraFrontEndOptions)
+          ? stringsArg(FlutterOptions.kExtraFrontEndOptions).toList()
          : <String>[];

    if (experiments.isNotEmpty) {
@ -591,6 +600,18 @@ abstract class FlutterCommand extends Command<void> {
      }
    }

+    if (argParser.options.containsKey(FlutterOptions.kNullSafety)) {
+      final bool nullSafety = boolArg(FlutterOptions.kNullSafety);
+      // Explicitly check for `true` and `false` so that `null` results in not
+      // passing a flag. This will use the automatically detected null-safety
+      // value based on the entrypoint
+      if (nullSafety == true) {
+        extraFrontEndOptions.add('--sound-null-safety');
+      } else if (nullSafety == false) {
+        extraFrontEndOptions.add('--no-sound-null-safety');
+      }
+    }
+
    final bool dartObfuscation = argParser.options.containsKey(FlutterOptions.kDartObfuscationOption)
      && boolArg(FlutterOptions.kDartObfuscationOption);

--- a/packages/flutter_tools/lib/src/test/flutter_platform.dart
+++ b/packages/flutter_tools/lib/src/test/flutter_platform.dart
@ -88,7 +88,7 @@ FlutterPlatform installHook({
  FlutterProject flutterProject,
  String icudtlPath,
  PlatformPluginRegistration platformPluginRegistration,
-  @required List<String> dartExperiments,
+  @required List<String> extraFrontEndOptions,
 }) {
  assert(testWrapper != null);
  assert(enableObservatory || (!startPaused && observatoryPort == null));
@ -121,7 +121,7 @@ FlutterPlatform installHook({
    projectRootDirectory: projectRootDirectory,
    flutterProject: flutterProject,
    icudtlPath: icudtlPath,
-    dartExperiments: dartExperiments,
+    extraFrontEndOptions: extraFrontEndOptions,
  );
  platformPluginRegistration(platform);
  return platform;
@ -269,7 +269,7 @@ class FlutterPlatform extends PlatformPlugin {
    this.projectRootDirectory,
    this.flutterProject,
    this.icudtlPath,
-    @required this.dartExperiments,
+    @required this.extraFrontEndOptions,
  }) : assert(shellPath != null);

  final String shellPath;
@ -290,7 +290,7 @@ class FlutterPlatform extends PlatformPlugin {
  final Uri projectRootDirectory;
  final FlutterProject flutterProject;
  final String icudtlPath;
-  final List<String> dartExperiments;
+  final List<String> extraFrontEndOptions;

  Directory fontsDirectory;

@ -459,7 +459,7 @@ class FlutterPlatform extends PlatformPlugin {

      if (precompiledDillPath == null && precompiledDillFiles == null) {
        // Lazily instantiate compiler so it is built only if it is actually used.
-        compiler ??= TestCompiler(buildMode, trackWidgetCreation, flutterProject, dartExperiments);
+        compiler ??= TestCompiler(buildMode, trackWidgetCreation, flutterProject, extraFrontEndOptions);
        mainDart = await compiler.compile(globals.fs.file(mainDart).uri);

        if (mainDart == null) {
@ -751,7 +751,7 @@ class FlutterPlatform extends PlatformPlugin {
      testConfigFile: findTestConfigFile(globals.fs.file(testUrl)),
      host: host,
      updateGoldens: updateGoldens,
-      nullSafety: dartExperiments.contains('non-nullable'),
+      nullSafety: extraFrontEndOptions?.contains('--enable-experiment=non-nullable') ?? false,
    );
  }

--- a/packages/flutter_tools/lib/src/test/runner.dart
+++ b/packages/flutter_tools/lib/src/test/runner.dart
@ -51,7 +51,7 @@ abstract class FlutterTestRunner {
    Directory coverageDirectory,
    bool web = false,
    String randomSeed,
-    @required List<String> dartExperiments,
+    @required List<String> extraFrontEndOptions,
  });
 }

@ -85,7 +85,7 @@ class _FlutterTestRunnerImpl implements FlutterTestRunner {
    Directory coverageDirectory,
    bool web = false,
    String randomSeed,
-    @required List<String> dartExperiments,
+    @required List<String> extraFrontEndOptions,
  }) async {
    // Configure package:test to use the Flutter engine for child processes.
    final String shellPath = globals.artifacts.getArtifactPath(Artifact.flutterTester);
@ -177,7 +177,7 @@ class _FlutterTestRunnerImpl implements FlutterTestRunner {
      projectRootDirectory: globals.fs.currentDirectory.uri,
      flutterProject: flutterProject,
      icudtlPath: icudtlPath,
-      dartExperiments: dartExperiments,
+      extraFrontEndOptions: extraFrontEndOptions,
    );

    // Make the global packages path absolute.
--- a/packages/flutter_tools/lib/src/test/test_compiler.dart
+++ b/packages/flutter_tools/lib/src/test/test_compiler.dart
@ -42,7 +42,7 @@ class TestCompiler {
    this.buildMode,
    this.trackWidgetCreation,
    this.flutterProject,
-    this.dartExperiments,
+    this.extraFrontEndOptions,
  ) : testFilePath = getKernelPathForTransformerOptions(
        globals.fs.path.join(flutterProject.directory.path, getBuildDirectory(), 'testfile.dill'),
        trackWidgetCreation: trackWidgetCreation,
@ -66,7 +66,7 @@ class TestCompiler {
  final BuildMode buildMode;
  final bool trackWidgetCreation;
  final String testFilePath;
-  final List<String> dartExperiments;
+  final List<String> extraFrontEndOptions;


  ResidentCompiler compiler;
@ -106,7 +106,7 @@ class TestCompiler {
      unsafePackageSerialization: false,
      dartDefines: const <String>[],
      packagesPath: globalPackagesPath,
-      experimentalFlags: dartExperiments,
+      extraFrontEndOptions: extraFrontEndOptions,
    );
    if (flutterProject.hasBuilders) {
      return CodeGeneratingResidentCompiler.create(
--- a/packages/flutter_tools/lib/src/web/compile.dart
+++ b/packages/flutter_tools/lib/src/web/compile.dart
@ -28,7 +28,6 @@ Future<void> buildWeb(
  BuildInfo buildInfo,
  bool initializePlatform,
  bool csp,
-  List<String> experiments,
 ) async {
  if (!flutterProject.web.existsSync()) {
    throwToolExit('Missing index.html.');
@ -53,8 +52,8 @@ Future<void> buildWeb(
        kDartDefines: encodeDartDefines(buildInfo.dartDefines),
        kCspMode: csp.toString(),
        kIconTreeShakerFlag: buildInfo.treeShakeIcons.toString(),
-        if (experiments.isNotEmpty)
-          kEnableExperiment: experiments?.join(','),
+        if (buildInfo.extraFrontEndOptions?.isNotEmpty ?? false)
+          kExtraFrontEndOptions: buildInfo.extraFrontEndOptions.join(',')
      },
      artifacts: globals.artifacts,
      fileSystem: globals.fs,
--- a/packages/flutter_tools/test/commands.shard/hermetic/build_linux_test.dart
+++ b/packages/flutter_tools/test/commands.shard/hermetic/build_linux_test.dart
@ -356,8 +356,8 @@ void main() {
      'set(PROJECT_DIR "${fileSystem.currentDirectory.path}")',
      '  "DART_DEFINES=\\"foo.bar%3D2,fizz.far%3D3\\""',
      '  "DART_OBFUSCATION=\\"true\\""',
-      '  "EXTRA_FRONT_END_OPTIONS=\\"--enable-experiment=non-nullable\\""',
-      '  "EXTRA_GEN_SNAPSHOT_OPTIONS=\\"--enable-experiment=non-nullable\\""',
+      '  "EXTRA_FRONT_END_OPTIONS=\\"--enable-experiment%3Dnon-nullable\\""',
+      '  "EXTRA_GEN_SNAPSHOT_OPTIONS=\\"--enable-experiment%3Dnon-nullable\\""',
      '  "SPLIT_DEBUG_INFO=\\"foo/\\""',
      '  "TRACK_WIDGET_CREATION=\\"true\\""',
      '  "TREE_SHAKE_ICONS=\\"true\\""',
--- a/packages/flutter_tools/test/commands.shard/hermetic/build_web_test.dart
+++ b/packages/flutter_tools/test/commands.shard/hermetic/build_web_test.dart
@ -56,7 +56,6 @@ void main() {
      BuildInfo.debug,
      false,
      false,
-      <String>[],
    ), throwsToolExit());
  }, overrides: <Type, Generator>{
    Platform: () => fakePlatform,
--- a/packages/flutter_tools/test/commands.shard/hermetic/build_windows_test.dart
+++ b/packages/flutter_tools/test/commands.shard/hermetic/build_windows_test.dart
@ -291,8 +291,8 @@ void main() {
    expect(props.findAllElements('FLUTTER_ROOT').first.text, flutterRoot);
    expect(props.findAllElements('TRACK_WIDGET_CREATION').first.text, 'true');
    expect(props.findAllElements('TREE_SHAKE_ICONS').first.text, 'true');
-    expect(props.findAllElements('EXTRA_GEN_SNAPSHOT_OPTIONS').first.text, '--enable-experiment=non-nullable');
-    expect(props.findAllElements('EXTRA_FRONT_END_OPTIONS').first.text, '--enable-experiment=non-nullable');
+    expect(props.findAllElements('EXTRA_GEN_SNAPSHOT_OPTIONS').first.text, '--enable-experiment%3Dnon-nullable');
+    expect(props.findAllElements('EXTRA_FRONT_END_OPTIONS').first.text, '--enable-experiment%3Dnon-nullable');
    expect(props.findAllElements('DART_DEFINES').first.text, 'foo%3Da,bar%3Db');
    expect(props.findAllElements('DART_OBFUSCATION').first.text, 'true');
    expect(props.findAllElements('SPLIT_DEBUG_INFO').first.text, r'C:\foo\');
--- a/packages/flutter_tools/test/commands.shard/hermetic/test_test.dart
+++ b/packages/flutter_tools/test/commands.shard/hermetic/test_test.dart
@ -184,7 +184,7 @@ class FakeFlutterTestRunner implements FlutterTestRunner {
    Directory coverageDirectory,
    bool web = false,
    String randomSeed,
-    @override List<String> dartExperiments,
+    @override List<String> extraFrontEndOptions,
  }) async {
    lastEnableObservatoryValue = enableObservatory;
    return exitCode;
--- a/packages/flutter_tools/test/general.shard/build_info_test.dart
+++ b/packages/flutter_tools/test/general.shard/build_info_test.dart
@ -113,8 +113,8 @@ void main() {
      'DART_DEFINES': 'foo%3D2,bar%3D2',
      'DART_OBFUSCATION': 'true',
      'SPLIT_DEBUG_INFO': 'foo/',
-      'EXTRA_FRONT_END_OPTIONS': '--enable-experiment=non-nullable,bar',
-      'EXTRA_GEN_SNAPSHOT_OPTIONS': '--enable-experiment=non-nullable,fizz',
+      'EXTRA_FRONT_END_OPTIONS': '--enable-experiment%3Dnon-nullable,bar',
+      'EXTRA_GEN_SNAPSHOT_OPTIONS': '--enable-experiment%3Dnon-nullable,fizz',
    });
  });

@ -129,18 +129,18 @@ void main() {
  testWithoutContext('decodeDartDefines decodes URI encoded dart defines', () {
    expect(decodeDartDefines(<String, String>{
      kDartDefines: '%22hello%22'
-    }), <String>['"hello"']);
+    }, kDartDefines), <String>['"hello"']);
    expect(decodeDartDefines(<String, String>{
      kDartDefines: 'https%3A%2F%2Fwww.google.com'
-    }), <String>['https://www.google.com']);
+    }, kDartDefines), <String>['https://www.google.com']);
    expect(decodeDartDefines(<String, String>{
      kDartDefines: '2%2C3%2C4,5'
-    }), <String>['2,3,4', '5']);
+    }, kDartDefines), <String>['2,3,4', '5']);
    expect(decodeDartDefines(<String, String>{
      kDartDefines: 'true,false,flase'
-    }), <String>['true', 'false', 'flase']);
+    }, kDartDefines), <String>['true', 'false', 'flase']);
    expect(decodeDartDefines(<String, String>{
      kDartDefines: '1232%2C456,2'
-    }), <String>['1232,456', '2']);
+    }, kDartDefines), <String>['1232,456', '2']);
  });
 }
--- a/packages/flutter_tools/test/general.shard/build_system/targets/web_test.dart
+++ b/packages/flutter_tools/test/general.shard/build_system/targets/web_test.dart
@ -255,7 +255,7 @@ void main() {

  test('Dart2JSTarget calls dart2js with expected args with enabled experiment', () => testbed.run(() async {
    environment.defines[kBuildMode] = 'profile';
-    environment.defines[kEnableExperiment] = 'non-nullable';
+    environment.defines[kExtraFrontEndOptions] = '--enable-experiment=non-nullable';
    processManager.addCommand(FakeCommand(
      command: <String>[
        ...kDart2jsLinuxArgs,
--- a/packages/flutter_tools/test/general.shard/flutter_platform_test.dart
+++ b/packages/flutter_tools/test/general.shard/flutter_platform_test.dart
@ -22,7 +22,7 @@ void main() {
        buildMode: BuildMode.debug,
        shellPath: '/',
        explicitObservatoryPort: 1234,
-        dartExperiments: <String>[],
+        extraFrontEndOptions: <String>[],
      );
      flutterPlatform.loadChannel('test1.dart', MockSuitePlatform());

@ -35,7 +35,7 @@ void main() {
        buildMode: BuildMode.debug,
        shellPath: '/',
        precompiledDillPath: 'example.dill',
-        dartExperiments: <String>[],
+        extraFrontEndOptions: <String>[],
      );
      flutterPlatform.loadChannel('test1.dart', MockSuitePlatform());

@ -113,7 +113,7 @@ void main() {
        shellPath: 'abc',
        enableObservatory: false,
        startPaused: true,
-        dartExperiments: <String>[],
+        extraFrontEndOptions: <String>[],
      ), throwsAssertionError);

      expect(() => installHook(
@ -122,7 +122,7 @@ void main() {
        enableObservatory: false,
        startPaused: false,
        observatoryPort: 123,
-        dartExperiments: <String>[],
+        extraFrontEndOptions: <String>[],
      ), throwsAssertionError);

      FlutterPlatform capturedPlatform;
@ -143,7 +143,7 @@ void main() {
        observatoryPort: 200,
        serverType: InternetAddressType.IPv6,
        icudtlPath: 'ghi',
-        dartExperiments: <String>[],
+        extraFrontEndOptions: <String>[],
        platformPluginRegistration: (FlutterPlatform platform) {
          capturedPlatform = platform;
        });
@ -192,7 +192,7 @@ class TestFlutterPlatform extends FlutterPlatform {
    startPaused: false,
    enableObservatory: false,
    buildTestAssets: false,
-    dartExperiments: <String>[],
+    extraFrontEndOptions: <String>[],
  );

  @override