[flutter_tool] Adds a flag to disable Impeller (#122960)

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

@@ -660,8 +660,10 @@ class AndroidDevice extends Device {
       ...<String>['--ez', 'cache-sksl', 'true'],
       if (debuggingOptions.purgePersistentCache)
         ...<String>['--ez', 'purge-persistent-cache', 'true'],
-      if (debuggingOptions.enableImpeller)
+      if (debuggingOptions.enableImpeller == ImpellerStatus.enabled)
         ...<String>['--ez', 'enable-impeller', 'true'],
+      if (debuggingOptions.enableImpeller == ImpellerStatus.disabled)
+        ...<String>['--ez', 'enable-impeller', 'false'],
       if (debuggingOptions.debuggingEnabled) ...<String>[
         if (debuggingOptions.buildInfo.isDebug) ...<String>[
           ...<String>['--ez', 'enable-checked-mode', 'true'],

packages/flutter_tools/lib/src/build_system/targets/shader_compiler.dart

@@ -17,6 +17,7 @@ import '../../base/logger.dart';
 import '../../build_info.dart';
 import '../../convert.dart';
 import '../../devfs.dart';
+import '../../device.dart';
 import '../build_system.dart';
 
 /// The output shader format that should be used by the [ShaderCompiler].
@@ -51,7 +52,7 @@ class DevelopmentShaderCompiler {
 
   /// Configure the output format of the shader compiler for a particular
   /// flutter device.
-  void configureCompiler(TargetPlatform? platform, { required bool enableImpeller }) {
+  void configureCompiler(TargetPlatform? platform, { required ImpellerStatus impellerStatus }) {
     switch (platform) {
       case TargetPlatform.ios:
         _shaderTarget = ShaderTarget.impelleriOS;
@@ -61,7 +62,9 @@ class DevelopmentShaderCompiler {
       case TargetPlatform.android_x86:
       case TargetPlatform.android_arm:
       case TargetPlatform.android:
-        _shaderTarget = enableImpeller ? ShaderTarget.impellerAndroid : ShaderTarget.sksl;
+        _shaderTarget = impellerStatus == ImpellerStatus.enabled
+          ? ShaderTarget.impellerAndroid
+          : ShaderTarget.sksl;
         break;
       case TargetPlatform.darwin:
       case TargetPlatform.linux_x64:
@@ -70,11 +73,11 @@ class DevelopmentShaderCompiler {
       case TargetPlatform.fuchsia_arm64:
       case TargetPlatform.fuchsia_x64:
       case TargetPlatform.tester:
-        assert(!enableImpeller);
+        assert(impellerStatus != ImpellerStatus.enabled);
         _shaderTarget = ShaderTarget.sksl;
         break;
       case TargetPlatform.web_javascript:
-        assert(!enableImpeller);
+        assert(impellerStatus != ImpellerStatus.enabled);
         _shaderTarget = ShaderTarget.sksl;
         _jsonMode = true;
         break;

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

@@ -193,7 +193,7 @@ abstract class RunCommandBase extends FlutterCommand with DeviceBasedDevelopment
   bool get cacheStartupProfile => boolArg('cache-startup-profile');
   bool get runningWithPrebuiltApplication => argResults![FlutterOptions.kUseApplicationBinary] != null;
   bool get trackWidgetCreation => boolArg('track-widget-creation');
-  bool get enableImpeller => boolArg('enable-impeller');
+  ImpellerStatus get enableImpeller => ImpellerStatus.fromBool(argResults!['enable-impeller'] as bool?);
   bool get uninstallFirst => boolArg('uninstall-first');
   bool get enableEmbedderApi => boolArg('enable-embedder-api');
 
@@ -478,7 +478,7 @@ class RunCommand extends RunCommandBase {
       commandRunProjectModule: FlutterProject.current().isModule,
       commandRunProjectHostLanguage: hostLanguage.join(','),
       commandRunAndroidEmbeddingVersion: androidEmbeddingVersion,
-      commandRunEnableImpeller: enableImpeller,
+      commandRunEnableImpeller: enableImpeller.asBool,
       commandRunIOSInterfaceType: iOSInterfaceType,
     );
   }

packages/flutter_tools/lib/src/device.dart

@@ -877,6 +877,23 @@ class _NoMemoryInfo implements MemoryInfo {
   Map<String, Object> toJson() => <String, Object>{};
 }
 
+enum ImpellerStatus {
+  platformDefault._(null),
+  enabled._(true),
+  disabled._(false);
+
+  const ImpellerStatus._(this.asBool);
+
+  factory ImpellerStatus.fromBool(bool? b) {
+    if (b == null) {
+      return platformDefault;
+    }
+    return b ? enabled : disabled;
+  }
+
+  final bool? asBool;
+}
+
 class DebuggingOptions {
   DebuggingOptions.enabled(
     this.buildInfo, {
@@ -917,7 +934,7 @@ class DebuggingOptions {
     this.vmserviceOutFile,
     this.fastStart = false,
     this.nativeNullAssertions = false,
-    this.enableImpeller = false,
+    this.enableImpeller = ImpellerStatus.platformDefault,
     this.uninstallFirst = false,
     this.serveObservatory = true,
     this.enableDartProfiling = true,
@@ -938,7 +955,7 @@ class DebuggingOptions {
       this.webLaunchUrl,
       this.cacheSkSL = false,
       this.traceAllowlist,
-      this.enableImpeller = false,
+      this.enableImpeller = ImpellerStatus.platformDefault,
       this.uninstallFirst = false,
       this.enableDartProfiling = true,
       this.enableEmbedderApi = false,
@@ -1048,7 +1065,7 @@ class DebuggingOptions {
   final bool webUseSseForDebugProxy;
   final bool webUseSseForDebugBackend;
   final bool webUseSseForInjectedClient;
-  final bool enableImpeller;
+  final ImpellerStatus enableImpeller;
   final bool serveObservatory;
   final bool enableDartProfiling;
   final bool enableEmbedderApi;
@@ -1123,7 +1140,8 @@ class DebuggingOptions {
       if (purgePersistentCache) '--purge-persistent-cache',
       if (route != null) '--route=$route',
       if (platformArgs['trace-startup'] as bool? ?? false) '--trace-startup',
-      if (enableImpeller) '--enable-impeller',
+      if (enableImpeller == ImpellerStatus.enabled) '--enable-impeller=true',
+      if (enableImpeller == ImpellerStatus.disabled) '--enable-impeller=false',
       if (environmentType == EnvironmentType.physical && deviceVmServicePort != null)
         '--vm-service-port=$deviceVmServicePort',
       // The simulator "device" is actually on the host machine so no ports will be forwarded.
@@ -1176,7 +1194,7 @@ class DebuggingOptions {
     'vmserviceOutFile': vmserviceOutFile,
     'fastStart': fastStart,
     'nativeNullAssertions': nativeNullAssertions,
-    'enableImpeller': enableImpeller,
+    'enableImpeller': enableImpeller.asBool,
     'serveObservatory': serveObservatory,
     'enableDartProfiling': enableDartProfiling,
     'enableEmbedderApi': enableEmbedderApi,
@@ -1223,7 +1241,7 @@ class DebuggingOptions {
       vmserviceOutFile: json['vmserviceOutFile'] as String?,
       fastStart: json['fastStart']! as bool,
       nativeNullAssertions: json['nativeNullAssertions']! as bool,
-      enableImpeller: (json['enableImpeller'] as bool?) ?? false,
+      enableImpeller: ImpellerStatus.fromBool(json['enableImpeller'] as bool?),
       uninstallFirst: (json['uninstallFirst'] as bool?) ?? false,
       serveObservatory: (json['serveObservatory'] as bool?) ?? false,
       enableDartProfiling: (json['enableDartProfiling'] as bool?) ?? true,

packages/flutter_tools/lib/src/run_hot.dart

@@ -253,7 +253,10 @@ class HotRunner extends ResidentRunner {
       await device!.initLogReader();
       device
         .developmentShaderCompiler
-        .configureCompiler(device.targetPlatform, enableImpeller: debuggingOptions.enableImpeller);
+        .configureCompiler(
+          device.targetPlatform,
+          impellerStatus: debuggingOptions.enableImpeller,
+        );
     }
     try {
       final List<Uri?> baseUris = await _initDevFS();

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

@@ -1017,11 +1017,13 @@ 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 and Android. This flag will '
-              'be ignored when targeting other platforms.',
+        defaultsTo: null,
+        help: 'Whether to enable the Impeller rendering engine. '
+              'Impeller is the default renderer on iOS. On Android, Impeller '
+              'is available but not the default. This flag will cause Impeller '
+              'to be used on Android. On other platforms, this flag will be '
+              'ignored.',
     );
   }
 

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

@@ -397,7 +397,7 @@ void main() {
     expect(options.traceSystrace, true);
     expect(options.verboseSystemLogs, true);
     expect(options.nativeNullAssertions, true);
-    expect(options.enableImpeller, true);
+    expect(options.enableImpeller, ImpellerStatus.enabled);
     expect(options.traceSystrace, true);
     expect(options.enableSoftwareRendering, true);
     expect(options.skiaDeterministicRendering, true);

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

@@ -428,7 +428,7 @@ void main() {
           TestUsageCommand('run', parameters: CustomDimensions.fromMap(<String, String>{
             'cd3': 'false', 'cd4': 'ios', 'cd22': 'iOS 13',
             'cd23': 'debug', 'cd18': 'false', 'cd15': 'swift', 'cd31': 'true',
-            'cd56': 'false', 'cd57': 'usb',
+            'cd57': 'usb',
           })
         )));
       }, overrides: <Type, Generator>{
@@ -699,7 +699,6 @@ void main() {
           commandRunModeName: 'debug',
           commandRunProjectModule: false,
           commandRunProjectHostLanguage: '',
-          commandRunEnableImpeller: false,
         ));
       }, overrides: <Type, Generator>{
         DeviceManager: () => testDeviceManager,
@@ -739,7 +738,6 @@ void main() {
           commandRunModeName: 'debug',
           commandRunProjectModule: false,
           commandRunProjectHostLanguage: '',
-          commandRunEnableImpeller: false,
           commandRunIOSInterfaceType: 'usb',
         ));
       }, overrides: <Type, Generator>{
@@ -783,7 +781,6 @@ void main() {
           commandRunModeName: 'debug',
           commandRunProjectModule: false,
           commandRunProjectHostLanguage: '',
-          commandRunEnableImpeller: false,
           commandRunIOSInterfaceType: 'wireless',
         ));
       }, overrides: <Type, Generator>{
@@ -827,7 +824,6 @@ void main() {
           commandRunModeName: 'debug',
           commandRunProjectModule: false,
           commandRunProjectHostLanguage: '',
-          commandRunEnableImpeller: false,
           commandRunIOSInterfaceType: 'wireless',
         ));
       }, overrides: <Type, Generator>{
@@ -1023,7 +1019,7 @@ void main() {
     expect(options.verboseSystemLogs, true);
     expect(options.nativeNullAssertions, true);
     expect(options.traceSystrace, true);
-    expect(options.enableImpeller, true);
+    expect(options.enableImpeller, ImpellerStatus.enabled);
     expect(options.enableSoftwareRendering, true);
     expect(options.skiaDeterministicRendering, true);
   }, overrides: <Type, Generator>{

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

@@ -278,7 +278,7 @@ void main() {
         purgePersistentCache: true,
         useTestFonts: true,
         verboseSystemLogs: true,
-        enableImpeller: true,
+        enableImpeller: ImpellerStatus.enabled,
       ),
       platformArgs: <String, dynamic>{},
       userIdentifier: '10',

packages/flutter_tools/test/general.shard/build_system/targets/shader_compiler_test.dart

@@ -11,6 +11,7 @@ import 'package:flutter_tools/src/base/logger.dart';
 import 'package:flutter_tools/src/build_info.dart';
 import 'package:flutter_tools/src/build_system/targets/shader_compiler.dart';
 import 'package:flutter_tools/src/devfs.dart';
+import 'package:flutter_tools/src/device.dart';
 
 import '../../../src/common.dart';
 import '../../../src/fake_process_manager.dart';
@@ -272,7 +273,10 @@ void main() {
       random: math.Random(0),
     );
 
-    developmentShaderCompiler.configureCompiler(TargetPlatform.android, enableImpeller: false);
+    developmentShaderCompiler.configureCompiler(
+      TargetPlatform.android,
+      impellerStatus: ImpellerStatus.disabled,
+    );
 
     final DevFSContent? content = await developmentShaderCompiler
       .recompileShader(DevFSFileContent(fileSystem.file(fragPath)));
@@ -317,7 +321,10 @@ void main() {
       random: math.Random(0),
     );
 
-    developmentShaderCompiler.configureCompiler(TargetPlatform.android, enableImpeller: true);
+    developmentShaderCompiler.configureCompiler(
+      TargetPlatform.android,
+      impellerStatus: ImpellerStatus.enabled,
+    );
 
     final DevFSContent? content = await developmentShaderCompiler
       .recompileShader(DevFSFileContent(fileSystem.file(fragPath)));
@@ -363,7 +370,10 @@ void main() {
       random: math.Random(0),
     );
 
-    developmentShaderCompiler.configureCompiler(TargetPlatform.web_javascript, enableImpeller: false);
+    developmentShaderCompiler.configureCompiler(
+      TargetPlatform.web_javascript,
+      impellerStatus: ImpellerStatus.disabled,
+    );
 
     final DevFSContent? content = await developmentShaderCompiler
       .recompileShader(DevFSFileContent(fileSystem.file(fragPath)));

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

@@ -282,7 +282,10 @@ class FakeShaderCompiler implements DevelopmentShaderCompiler {
   const FakeShaderCompiler();
 
   @override
-  void configureCompiler(TargetPlatform? platform, { required bool enableImpeller }) { }
+  void configureCompiler(
+    TargetPlatform? platform, {
+    required ImpellerStatus impellerStatus,
+  }) { }
 
   @override
   Future<DevFSContent> recompileShader(DevFSContent inputShader) {

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

@@ -20,6 +20,7 @@ import 'package:flutter_tools/src/build_info.dart';
 import 'package:flutter_tools/src/build_system/targets/shader_compiler.dart';
 import 'package:flutter_tools/src/compile.dart';
 import 'package:flutter_tools/src/devfs.dart';
+import 'package:flutter_tools/src/device.dart';
 import 'package:flutter_tools/src/vmservice.dart';
 import 'package:package_config/package_config.dart';
 import 'package:test/fake.dart';
@@ -807,7 +808,10 @@ class FakeShaderCompiler implements DevelopmentShaderCompiler {
   const FakeShaderCompiler();
 
   @override
-  void configureCompiler(TargetPlatform? platform, { required bool enableImpeller }) { }
+  void configureCompiler(
+    TargetPlatform? platform, {
+    required ImpellerStatus impellerStatus,
+  }) { }
 
   @override
   Future<DevFSContent> recompileShader(DevFSContent inputShader) async {

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

@@ -716,7 +716,7 @@ void main() {
         dartEntrypointArgs: <String>['a', 'b'],
         dartFlags: 'c',
         deviceVmServicePort: 1234,
-        enableImpeller: true,
+        enableImpeller: ImpellerStatus.enabled,
         enableDartProfiling: false,
         enableEmbedderApi: true,
       );
@@ -755,7 +755,7 @@ void main() {
         cacheSkSL: true,
         purgePersistentCache: true,
         verboseSystemLogs: true,
-        enableImpeller: true,
+        enableImpeller: ImpellerStatus.disabled,
         deviceVmServicePort: 0,
         hostVmServicePort: 1,
       );
@@ -792,7 +792,7 @@ void main() {
           '--purge-persistent-cache',
           '--route=/test',
           '--trace-startup',
-          '--enable-impeller',
+          '--enable-impeller=false',
           '--vm-service-port=0',
         ].join(' '),
       );
@@ -871,7 +871,7 @@ void main() {
         BuildInfo.debug,
         traceAllowlist: 'foo',
         cacheSkSL: true,
-        enableImpeller: true,
+        enableImpeller: ImpellerStatus.disabled,
       );
 
       final List<String> launchArguments = original.getIOSLaunchArguments(
@@ -890,7 +890,7 @@ void main() {
           '--cache-sksl',
           '--route=/test',
           '--trace-startup',
-          '--enable-impeller',
+          '--enable-impeller=false',
         ].join(' '),
       );
     });
@@ -914,7 +914,7 @@ void main() {
         cacheSkSL: true,
         purgePersistentCache: true,
         verboseSystemLogs: true,
-        enableImpeller: true,
+        enableImpeller: ImpellerStatus.disabled,
         deviceVmServicePort: 0,
         hostVmServicePort: 1,
       );
@@ -951,7 +951,7 @@ void main() {
           '--purge-persistent-cache',
           '--route=/test',
           '--trace-startup',
-          '--enable-impeller',
+          '--enable-impeller=false',
           '--vm-service-port=1',
         ].join(' '),
       );

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

@@ -752,7 +752,10 @@ class FakeShaderCompiler implements DevelopmentShaderCompiler {
   const FakeShaderCompiler();
 
   @override
-  void configureCompiler(TargetPlatform? platform, { required bool enableImpeller }) { }
+  void configureCompiler(
+    TargetPlatform? platform, {
+    required ImpellerStatus impellerStatus,
+  }) { }
 
   @override
   Future<DevFSContent> recompileShader(DevFSContent inputShader) {

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

@@ -352,7 +352,7 @@ void main() {
             '--verbose-logging',
             '--cache-sksl',
             '--purge-persistent-cache',
-            '--enable-impeller',
+            '--enable-impeller=false',
             '--enable-embedder-api',
           ].join(' '),
         ],
@@ -404,7 +404,7 @@ void main() {
         cacheSkSL: true,
         purgePersistentCache: true,
         verboseSystemLogs: true,
-        enableImpeller: true,
+        enableImpeller: ImpellerStatus.disabled,
         enableEmbedderApi: true,
       ),
       platformArgs: <String, dynamic>{},

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

@@ -1041,7 +1041,7 @@ Dec 20 17:04:32 md32-11-vm1 Another App[88374]: Ignore this text'''
         cacheSkSL: true,
         purgePersistentCache: true,
         dartFlags: '--baz',
-        enableImpeller: true,
+        enableImpeller: ImpellerStatus.disabled,
         hostVmServicePort: 0,
       );
 
@@ -1065,7 +1065,7 @@ Dec 20 17:04:32 md32-11-vm1 Another App[88374]: Ignore this text'''
         '--cache-sksl',
         '--purge-persistent-cache',
         '--dart-flags=--baz',
-        '--enable-impeller',
+        '--enable-impeller=false',
         '--vm-service-port=0',
       ]));
     }, overrides: <Type, Generator>{

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

@@ -2817,7 +2817,10 @@ class FakeShaderCompiler implements DevelopmentShaderCompiler {
   const FakeShaderCompiler();
 
   @override
-  void configureCompiler(TargetPlatform? platform, { required bool enableImpeller }) { }
+  void configureCompiler(
+    TargetPlatform? platform, {
+    required ImpellerStatus impellerStatus,
+  }) { }
 
   @override
   Future<DevFSContent> recompileShader(DevFSContent inputShader) {

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

@@ -1682,7 +1682,10 @@ class FakeShaderCompiler implements DevelopmentShaderCompiler {
   const FakeShaderCompiler();
 
   @override
-  void configureCompiler(TargetPlatform? platform, { required bool enableImpeller }) { }
+  void configureCompiler(
+    TargetPlatform? platform, {
+    required ImpellerStatus impellerStatus,
+  }) { }
 
   @override
   Future<DevFSContent> recompileShader(DevFSContent inputShader) {

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

@@ -1518,7 +1518,10 @@ class FakeShaderCompiler implements DevelopmentShaderCompiler {
   const FakeShaderCompiler();
 
   @override
-  void configureCompiler(TargetPlatform? platform, { required bool enableImpeller }) { }
+  void configureCompiler(
+    TargetPlatform? platform, {
+    required ImpellerStatus impellerStatus,
+  }) { }
 
   @override
   Future<DevFSContent> recompileShader(DevFSContent inputShader) {

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

@@ -16,6 +16,7 @@ import 'package:flutter_tools/src/build_system/targets/shader_compiler.dart';
 import 'package:flutter_tools/src/compile.dart';
 import 'package:flutter_tools/src/convert.dart';
 import 'package:flutter_tools/src/devfs.dart';
+import 'package:flutter_tools/src/device.dart';
 import 'package:flutter_tools/src/globals.dart' as globals;
 import 'package:flutter_tools/src/html_utils.dart';
 import 'package:flutter_tools/src/isolated/devfs_web.dart';
@@ -1176,7 +1177,10 @@ class FakeShaderCompiler implements DevelopmentShaderCompiler {
   const FakeShaderCompiler();
 
   @override
-  void configureCompiler(TargetPlatform? platform, { required bool enableImpeller }) { }
+  void configureCompiler(
+    TargetPlatform? platform, {
+    required ImpellerStatus impellerStatus,
+  }) { }
 
   @override
   Future<DevFSContent> recompileShader(DevFSContent inputShader) {