[flutter_tools] wire up alternative invalidation strategy to features (#70865)

packages/flutter_tools/lib/src/features.dart

@@ -49,6 +49,9 @@ abstract class FeatureFlags {
   /// Whether fast single widget reloads are enabled.
   bool get isSingleWidgetReloadEnabled => false;
 
+  /// Whether the CFE experimental invalidation strategy is enabled.
+  bool get isExperimentalInvalidationStrategyEnabled => false;
+
   /// Whether a particular feature is enabled for the current channel.
   ///
   /// Prefer using one of the specific getters above instead of this API.
@@ -92,6 +95,9 @@ class FlutterFeatureFlags implements FeatureFlags {
   @override
   bool get isSingleWidgetReloadEnabled => isEnabled(singleWidgetReload);
 
+  @override
+  bool get isExperimentalInvalidationStrategyEnabled => isEnabled(experimentalInvalidationStrategy);
+
   @override
   bool isEnabled(Feature feature) {
     final String currentChannel = _flutterVersion.channel;
@@ -125,6 +131,7 @@ const List<Feature> allFeatures = <Feature>[
   flutterAndroidFeature,
   flutterIOSFeature,
   flutterFuchsiaFeature,
+  experimentalInvalidationStrategy,
 ];
 
 /// The [Feature] for flutter web.
@@ -270,6 +277,29 @@ const Feature singleWidgetReload = Feature(
   ),
 );
 
+/// The CFE experimental invalidation strategy.
+const Feature experimentalInvalidationStrategy = Feature(
+  name: 'Hot reload optimization that reduces incremental artifact size',
+  configSetting: 'experimental-invalidation-strategy',
+  environmentOverride: 'FLUTTER_CFE_EXPERIMENTAL_INVALIDATION',
+  master: FeatureChannelSetting(
+    available: true,
+    enabledByDefault: true,
+  ),
+  dev: FeatureChannelSetting(
+    available: true,
+    enabledByDefault: false,
+  ),
+  beta: FeatureChannelSetting(
+    available: true,
+    enabledByDefault: false,
+  ),
+  stable: FeatureChannelSetting(
+    available: true,
+    enabledByDefault: false,
+  ),
+);
+
 /// A [Feature] is a process for conditionally enabling tool features.
 ///
 /// All settings are optional, and if not provided will generally default to

packages/flutter_tools/lib/src/resident_runner.dart

@@ -139,12 +139,13 @@ class FlutterDevice {
     } else {
       // The flutter-widget-cache feature only applies to run mode.
       List<String> extraFrontEndOptions = buildInfo.extraFrontEndOptions;
-      if (featureFlags.isSingleWidgetReloadEnabled) {
-        extraFrontEndOptions = <String>[
-          '--flutter-widget-cache',
-          ...?extraFrontEndOptions,
-        ];
-      }
+      extraFrontEndOptions = <String>[
+        if (featureFlags.isSingleWidgetReloadEnabled)
+         '--flutter-widget-cache',
+        if (featureFlags.isExperimentalInvalidationStrategyEnabled)
+          '--enable-experiment=alternative-invalidation-strategy',
+        ...?extraFrontEndOptions,
+      ];
       generator = ResidentCompiler(
         globals.artifacts.getArtifactPath(
           Artifact.flutterPatchedSdkPath,

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

@@ -2578,6 +2578,33 @@ void main() {
     FeatureFlags: () => TestFeatureFlags(isSingleWidgetReloadEnabled: true)
   });
 
+   testUsingContext('FlutterDevice passes alternative-invalidation-strategy flag when feature is enabled', () async {
+    fakeVmServiceHost = FakeVmServiceHost(requests: <VmServiceExpectation>[]);
+    final MockDevice mockDevice = MockDevice();
+    when(mockDevice.targetPlatform).thenAnswer((Invocation invocation) async {
+      return TargetPlatform.android_arm;
+    });
+
+    final DefaultResidentCompiler residentCompiler = (await FlutterDevice.create(
+      mockDevice,
+      buildInfo: const BuildInfo(
+        BuildMode.debug,
+        '',
+        treeShakeIcons: false,
+        extraFrontEndOptions: <String>[],
+      ),
+      target: null, platform: null,
+    )).generator as DefaultResidentCompiler;
+
+    expect(residentCompiler.extraFrontEndOptions,
+      contains('--enable-experiment=alternative-invalidation-strategy'));
+  }, overrides: <Type, Generator>{
+    Artifacts: () => Artifacts.test(),
+    FileSystem: () => MemoryFileSystem.test(),
+    ProcessManager: () => FakeProcessManager.any(),
+    FeatureFlags: () => TestFeatureFlags(isExperimentalInvalidationStrategyEnabled: true)
+  });
+
   testUsingContext('connect sets up log reader', () => testbed.run(() async {
     fakeVmServiceHost = FakeVmServiceHost(requests: <VmServiceExpectation>[]);
     final MockDevice mockDevice = MockDevice();

packages/flutter_tools/test/src/testbed.dart

@@ -730,7 +730,8 @@ class TestFeatureFlags implements FeatureFlags {
     this.isAndroidEnabled = true,
     this.isIOSEnabled = true,
     this.isFuchsiaEnabled = false,
-});
+    this.isExperimentalInvalidationStrategyEnabled = false,
+  });
 
   @override
   final bool isLinuxEnabled;
@@ -756,6 +757,9 @@ class TestFeatureFlags implements FeatureFlags {
   @override
   final bool isFuchsiaEnabled;
 
+  @override
+  final bool isExperimentalInvalidationStrategyEnabled;
+
   @override
   bool isEnabled(Feature feature) {
     switch (feature) {
@@ -775,6 +779,8 @@ class TestFeatureFlags implements FeatureFlags {
         return isIOSEnabled;
       case flutterFuchsiaFeature:
         return isFuchsiaEnabled;
+      case experimentalInvalidationStrategy:
+        return isExperimentalInvalidationStrategyEnabled;
     }
     return false;
   }