[flutter_tool] Adds --enable-impeller flag to the run command (#100835)

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

@@ -140,7 +140,7 @@ abstract class RunCommandBase extends FlutterCommand with DeviceBasedDevelopment
               'startup. By default this is main(List<String> args). Specify '
               'this option multiple times each with one argument to pass '
               'multiple arguments to the Dart entrypoint. Currently this is '
-              'only supported on desktop platforms.'
+              'only supported on desktop platforms.',
     );
     usesWebOptions(verboseHelp: verboseHelp);
     usesTargetOption();
@@ -155,6 +155,7 @@ abstract class RunCommandBase extends FlutterCommand with DeviceBasedDevelopment
     addDevToolsOptions(verboseHelp: verboseHelp);
     addAndroidSpecificBuildOptions(hide: !verboseHelp);
     usesFatalWarningsOption(verboseHelp: verboseHelp);
+    addEnableImpellerFlag(verboseHelp: verboseHelp);
   }
 
   bool get traceStartup => boolArg('trace-startup');
@@ -164,6 +165,7 @@ abstract class RunCommandBase extends FlutterCommand with DeviceBasedDevelopment
   bool get disableServiceAuthCodes => boolArg('disable-service-auth-codes');
   bool get runningWithPrebuiltApplication => argResults['use-application-binary'] != null;
   bool get trackWidgetCreation => boolArg('track-widget-creation');
+  bool get enableImpeller => boolArg('enable-impeller');
 
   @override
   bool get reportNullSafety => true;
@@ -193,6 +195,7 @@ abstract class RunCommandBase extends FlutterCommand with DeviceBasedDevelopment
         webEnableExposeUrl: featureFlags.isWebEnabled && boolArg('web-allow-expose-url'),
         webRunHeadless: featureFlags.isWebEnabled && boolArg('web-run-headless'),
         webBrowserDebugPort: browserDebugPort,
+        enableImpeller: enableImpeller,
       );
     } else {
       return DebuggingOptions.enabled(
@@ -235,6 +238,7 @@ abstract class RunCommandBase extends FlutterCommand with DeviceBasedDevelopment
           && !runningWithPrebuiltApplication,
         nullAssertions: boolArg('null-assertions'),
         nativeNullAssertions: boolArg('native-null-assertions'),
+        enableImpeller: enableImpeller,
       );
     }
   }
@@ -438,6 +442,7 @@ class RunCommand extends RunCommandBase {
       commandRunProjectModule: FlutterProject.current().isModule,
       commandRunProjectHostLanguage: hostLanguage.join(','),
       commandRunAndroidEmbeddingVersion: androidEmbeddingVersion,
+      commandRunEnableImpeller: enableImpeller,
     );
   }
 

packages/flutter_tools/lib/src/device.dart

@@ -790,6 +790,7 @@ class DebuggingOptions {
     this.fastStart = false,
     this.nullAssertions = false,
     this.nativeNullAssertions = false,
+    this.enableImpeller = false,
    }) : debuggingEnabled = true;
 
   DebuggingOptions.disabled(this.buildInfo, {
@@ -805,6 +806,7 @@ class DebuggingOptions {
       this.webLaunchUrl,
       this.cacheSkSL = false,
       this.traceAllowlist,
+      this.enableImpeller = false,
     }) : debuggingEnabled = false,
       useTestFonts = false,
       startPaused = false,
@@ -870,6 +872,7 @@ class DebuggingOptions {
     required this.fastStart,
     required this.nullAssertions,
     required this.nativeNullAssertions,
+    required this.enableImpeller,
   });
 
   final bool debuggingEnabled;
@@ -903,6 +906,7 @@ class DebuggingOptions {
   final bool webUseSseForDebugProxy;
   final bool webUseSseForDebugBackend;
   final bool webUseSseForInjectedClient;
+  final bool enableImpeller;
 
   /// Whether to run the browser in headless mode.
   ///
@@ -972,6 +976,7 @@ class DebuggingOptions {
     'fastStart': fastStart,
     'nullAssertions': nullAssertions,
     'nativeNullAssertions': nativeNullAssertions,
+    'enableImpeller': enableImpeller,
   };
 
   static DebuggingOptions fromJson(Map<String, Object?> json, BuildInfo buildInfo) =>
@@ -1014,6 +1019,7 @@ class DebuggingOptions {
       fastStart: (json['fastStart'] as bool?)!,
       nullAssertions: (json['nullAssertions'] as bool?)!,
       nativeNullAssertions: (json['nativeNullAssertions'] as bool?)!,
+      enableImpeller: (json['enableImpeller'] as bool?) ?? false,
     );
 }
 

packages/flutter_tools/lib/src/ios/devices.dart

@@ -373,6 +373,7 @@ class IOSDevice extends Device {
       if (debuggingOptions.purgePersistentCache) '--purge-persistent-cache',
       if (route != null) '--route=$route',
       if (platformArgs['trace-startup'] as bool? ?? false) '--trace-startup',
+      if (debuggingOptions.enableImpeller) '--enable-impeller',
     ];
 
     final Status installStatus = _logger.startProgress(

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

@@ -66,6 +66,7 @@ class CustomDimensions {
     this.hotEventScannedSourcesCount,
     this.hotEventReassembleTimeInMs,
     this.hotEventReloadVMTimeInMs,
+    this.commandRunEnableImpeller,
   });
 
   final String? sessionHostOsDetails;  // cd1
@@ -123,6 +124,7 @@ class CustomDimensions {
   final int? hotEventScannedSourcesCount;  // cd 53
   final int? hotEventReassembleTimeInMs;  // cd 54
   final int? hotEventReloadVMTimeInMs;  // cd 55
+  final bool? commandRunEnableImpeller;  // cd 56
 
   /// Convert to a map that will be used to upload to the analytics backend.
   Map<String, String> toMap() => <String, String>{
@@ -181,6 +183,7 @@ class CustomDimensions {
       if (hotEventScannedSourcesCount != null) cdKey(CustomDimensionsEnum.hotEventScannedSourcesCount): hotEventScannedSourcesCount.toString(),
       if (hotEventReassembleTimeInMs != null) cdKey(CustomDimensionsEnum.hotEventReassembleTimeInMs): hotEventReassembleTimeInMs.toString(),
       if (hotEventReloadVMTimeInMs != null) cdKey(CustomDimensionsEnum.hotEventReloadVMTimeInMs): hotEventReloadVMTimeInMs.toString(),
+      if (commandRunEnableImpeller != null) cdKey(CustomDimensionsEnum.commandRunEnableImpeller): commandRunEnableImpeller.toString(),
     };
 
   /// Merge the values of two [CustomDimensions] into one. If a value is defined
@@ -246,6 +249,7 @@ class CustomDimensions {
       hotEventScannedSourcesCount: other.hotEventScannedSourcesCount ?? hotEventScannedSourcesCount,
       hotEventReassembleTimeInMs: other.hotEventReassembleTimeInMs ?? hotEventReassembleTimeInMs,
       hotEventReloadVMTimeInMs: other.hotEventReloadVMTimeInMs ?? hotEventReloadVMTimeInMs,
+      commandRunEnableImpeller: other.commandRunEnableImpeller ?? commandRunEnableImpeller,
     );
   }
 
@@ -305,6 +309,7 @@ class CustomDimensions {
       hotEventScannedSourcesCount: _extractInt(map, CustomDimensionsEnum.hotEventScannedSourcesCount),
       hotEventReassembleTimeInMs: _extractInt(map, CustomDimensionsEnum.hotEventReassembleTimeInMs),
       hotEventReloadVMTimeInMs: _extractInt(map, CustomDimensionsEnum.hotEventReloadVMTimeInMs),
+      commandRunEnableImpeller: _extractBool(map, CustomDimensionsEnum.commandRunEnableImpeller),
     );
 
   static bool? _extractBool(Map<String, String> map, CustomDimensionsEnum field) =>
@@ -390,6 +395,7 @@ enum CustomDimensionsEnum {
   hotEventScannedSourcesCount,  // cd53
   hotEventReassembleTimeInMs,  // cd54
   hotEventReloadVMTimeInMs,  // cd55
+  commandRunEnableImpeller,  // cd56
 }
 
 String cdKey(CustomDimensionsEnum cd) => 'cd${cd.index + 1}';

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

@@ -948,6 +948,16 @@ abstract class FlutterCommand extends Command<void> {
     );
   }
 
+  void addEnableImpellerFlag({required bool verboseHelp}) {
+    argParser.addFlag('enable-impeller',
+        negatable: false,
+        hide: !verboseHelp,
+        help: 'Whether to enable the experimental Impeller rendering engine. '
+              'Impeller is currently only supported on iOS. This flag will '
+              'be ignored when targeting other platforms.',
+    );
+  }
+
   /// Compute the [BuildInfo] for the current flutter command.
   /// Commands that build multiple build modes can pass in a [forcedBuildMode]
   /// to be used instead of parsing flags.

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

@@ -207,6 +207,26 @@ void main() {
     ProcessManager: () => FakeProcessManager.any(),
     Pub: () => FakePub(),
   });
+
+  testUsingContext('--enable-impeller flag propagates to debugging options', () async {
+    final DriveCommand command = DriveCommand(fileSystem: fileSystem, logger: logger, platform: platform);
+    fileSystem.file('lib/main.dart').createSync(recursive: true);
+    fileSystem.file('test_driver/main_test.dart').createSync(recursive: true);
+    fileSystem.file('pubspec.yaml').createSync();
+
+    await expectLater(() => createTestCommandRunner(command).run(<String>[
+      'drive',
+      '--enable-impeller',
+    ]), throwsToolExit());
+
+    final DebuggingOptions options = await command.createDebuggingOptions(false);
+
+    expect(options.enableImpeller, true);
+  }, overrides: <Type, Generator>{
+    Cache: () => Cache.test(processManager: FakeProcessManager.any()),
+    FileSystem: () => MemoryFileSystem.test(),
+    ProcessManager: () => FakeProcessManager.any(),
+  });
 }
 
 // Unfortunately Device, despite not being immutable, has an `operator ==`.

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

@@ -394,6 +394,7 @@ void main() {
           TestUsageCommand('run', parameters: CustomDimensions.fromMap(<String, String>{
             'cd3': 'false', 'cd4': 'ios', 'cd22': 'iOS 13',
             'cd23': 'debug', 'cd18': 'false', 'cd15': 'swift', 'cd31': 'false',
+            'cd56': 'false',
           })
         )));
       }, overrides: <Type, Generator>{
@@ -622,6 +623,22 @@ void main() {
     ProcessManager: () => FakeProcessManager.any(),
   });
 
+  testUsingContext('--enable-impeller flag propagates to debugging options', () async {
+    final RunCommand command = RunCommand();
+    await expectLater(() => createTestCommandRunner(command).run(<String>[
+      'run',
+      '--enable-impeller',
+    ]), throwsToolExit());
+
+    final DebuggingOptions options = await command.createDebuggingOptions(false);
+
+    expect(options.enableImpeller, true);
+  }, overrides: <Type, Generator>{
+    Cache: () => Cache.test(processManager: FakeProcessManager.any()),
+    FileSystem: () => MemoryFileSystem.test(),
+    ProcessManager: () => FakeProcessManager.any(),
+  });
+
   testUsingContext('fails when "--web-launch-url" is not supported', () async {
     final RunCommand command = RunCommand();
     await expectLater(

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

@@ -521,6 +521,7 @@ void main() {
         dartEntrypointArgs: <String>['a', 'b'],
         dartFlags: 'c',
         deviceVmServicePort: 1234,
+        enableImpeller: true,
       );
       final String jsonString = json.encode(original.toJson());
       final Map<String, dynamic> decoded = castStringKeyedMap(json.decode(jsonString))!;
@@ -531,6 +532,7 @@ void main() {
       expect(deserialized.dartEntrypointArgs, original.dartEntrypointArgs);
       expect(deserialized.dartFlags, original.dartFlags);
       expect(deserialized.deviceVmServicePort, original.deviceVmServicePort);
+      expect(deserialized.enableImpeller, original.enableImpeller);
     });
   });
 }

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

@@ -285,6 +285,7 @@ void main() {
             '--verbose-logging',
             '--cache-sksl',
             '--purge-persistent-cache',
+            '--enable-impeller',
           ].join(' '),
         ], environment: const <String, String>{
         'PATH': '/usr/bin:null',
@@ -332,6 +333,7 @@ void main() {
         purgePersistentCache: true,
         verboseSystemLogs: true,
         nullAssertions: true,
+        enableImpeller: true,
       ),
       platformArgs: <String, dynamic>{},
     );