delete fast reassemble code (#102842)

packages/flutter/lib/src/foundation/binding.dart

@@ -157,13 +157,6 @@ abstract class BindingBase {
   static Type? _debugInitializedType;
   static bool _debugServiceExtensionsRegistered = false;
 
-  /// Additional configuration used by the framework during hot reload.
-  ///
-  /// See also:
-  ///
-  ///  * [DebugReassembleConfig], which describes the configuration.
-  static DebugReassembleConfig? debugReassembleConfig;
-
   /// The main window to which this binding is bound.
   ///
   /// A number of additional bindings are defined as extensions of
@@ -878,23 +871,3 @@ abstract class BindingBase {
 Future<void> _exitApplication() async {
   exit(0);
 }
-
-/// Additional configuration used for hot reload reassemble optimizations.
-///
-/// Do not extend, implement, or mixin this class. This may only be instantiated
-/// in debug mode.
-class DebugReassembleConfig {
-  /// Create a new [DebugReassembleConfig].
-  ///
-  /// Throws a [FlutterError] if this is called in profile or release mode.
-  DebugReassembleConfig({
-    this.widgetName,
-  }) {
-    if (!kDebugMode) {
-      throw FlutterError('Cannot instantiate DebugReassembleConfig in profile or release mode.');
-    }
-  }
-
-  /// The name of the widget that was modified, or `null` if the change was elsewhere.
-  final String? widgetName;
-}

packages/flutter/lib/src/rendering/binding.dart

@@ -514,7 +514,6 @@ mixin RendererBinding on BindingBase, ServicesBinding, SchedulerBinding, Gesture
   @override
   Future<void> performReassemble() async {
     await super.performReassemble();
-    if (BindingBase.debugReassembleConfig?.widgetName == null) {
     if (!kReleaseMode) {
       Timeline.startSync('Preparing Hot Reload (layout)');
     }
@@ -525,7 +524,6 @@ mixin RendererBinding on BindingBase, ServicesBinding, SchedulerBinding, Gesture
         Timeline.finishSync();
       }
     }
-    }
     scheduleWarmUpFrame();
     await endOfFrame;
   }

packages/flutter/lib/src/widgets/binding.dart

@@ -412,16 +412,7 @@ mixin WidgetsBinding on BindingBase, ServicesBinding, SchedulerBinding, GestureB
       registerServiceExtension(
         name: 'fastReassemble',
         callback: (Map<String, Object> params) async {
-          // This mirrors the implementation of the 'reassemble' callback registration
-          // in lib/src/foundation/binding.dart, but with the extra binding config used
-          // to skip some reassemble work.
-          final String? className = params['className'] as String?;
-          BindingBase.debugReassembleConfig = DebugReassembleConfig(widgetName: className);
-          try {
           await reassembleApplication();
-          } finally {
-            BindingBase.debugReassembleConfig = null;
-          }
           return <String, String>{'type': 'Success'};
         },
       );
@@ -478,7 +469,7 @@ mixin WidgetsBinding on BindingBase, ServicesBinding, SchedulerBinding, GestureB
 
   Future<void> _forceRebuild() {
     if (renderViewElement != null) {
-      buildOwner!.reassemble(renderViewElement!, null);
+      buildOwner!.reassemble(renderViewElement!);
       return endOfFrame;
     }
     return Future<void>.value();
@@ -945,7 +936,7 @@ mixin WidgetsBinding on BindingBase, ServicesBinding, SchedulerBinding, GestureB
     }());
 
     if (renderViewElement != null) {
-      buildOwner!.reassemble(renderViewElement!, BindingBase.debugReassembleConfig);
+      buildOwner!.reassemble(renderViewElement!);
     }
     return super.performReassemble();
   }

packages/flutter/lib/src/widgets/framework.dart

@@ -3028,14 +3028,13 @@ class BuildOwner {
   /// changed implementations.
   ///
   /// This is expensive and should not be called except during development.
-  void reassemble(Element root, DebugReassembleConfig? reassembleConfig) {
+  void reassemble(Element root) {
     if (!kReleaseMode) {
       Timeline.startSync('Preparing Hot Reload (widgets)');
     }
     try {
       assert(root._parent == null);
       assert(root.owner == this);
-      root._debugReassembleConfig = reassembleConfig;
       root.reassemble();
     } finally {
       if (!kReleaseMode) {
@@ -3143,7 +3142,6 @@ abstract class Element extends DiagnosticableTree implements BuildContext {
       _widget = widget;
 
   Element? _parent;
-  DebugReassembleConfig? _debugReassembleConfig;
   _NotificationNode? _notificationTree;
 
   /// Compare two widgets for equality.
@@ -3273,15 +3271,10 @@ abstract class Element extends DiagnosticableTree implements BuildContext {
   @mustCallSuper
   @protected
   void reassemble() {
-    if (_debugShouldReassemble(_debugReassembleConfig, _widget)) {
     markNeedsBuild();
-      _debugReassembleConfig = null;
-    }
     visitChildren((Element child) {
-      child._debugReassembleConfig = _debugReassembleConfig;
       child.reassemble();
     });
-    _debugReassembleConfig = null;
   }
 
   bool _debugIsInScope(Element target) {
@@ -4925,9 +4918,7 @@ class StatefulElement extends ComponentElement {
 
   @override
   void reassemble() {
-    if (_debugShouldReassemble(_debugReassembleConfig, _widget)) {
     state.reassemble();
-    }
     super.reassemble();
   }
 
@@ -6463,9 +6454,3 @@ class _NullWidget extends Widget {
   @override
   Element createElement() => throw UnimplementedError();
 }
-
-// Whether a [DebugReassembleConfig] indicates that an element holding [widget] can skip
-// a reassemble.
-bool _debugShouldReassemble(DebugReassembleConfig? config, Widget? widget) {
-  return config == null || config.widgetName == null || widget?.runtimeType.toString() == config.widgetName;
-}

packages/flutter/lib/src/widgets/widget_inspector.dart

@@ -911,7 +911,7 @@ mixin WidgetInspectorService {
   Future<void> forceRebuild() {
     final WidgetsBinding binding = WidgetsBinding.instance;
     if (binding.renderViewElement != null) {
-      binding.buildOwner!.reassemble(binding.renderViewElement!, null);
+      binding.buildOwner!.reassemble(binding.renderViewElement!);
       return binding.endOfFrame;
     }
     return Future<void>.value();

packages/flutter/test/widgets/fast_reassemble_test.dart

-// 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:flutter/foundation.dart';
-import 'package:flutter/widgets.dart';
-import 'package:flutter_test/flutter_test.dart';
-
-void main() {
-  testWidgets('reassemble with a className only marks subtrees from the first matching element as dirty', (WidgetTester tester) async {
-    await tester.pumpWidget(
-      const Foo(Bar(Fizz(SizedBox())))
-    );
-
-    expect(Foo.count, 0);
-    expect(Bar.count, 0);
-    expect(Fizz.count, 0);
-
-    DebugReassembleConfig config = DebugReassembleConfig(widgetName: 'Bar');
-    WidgetsBinding.instance.buildOwner!.reassemble(WidgetsBinding.instance.renderViewElement!, config);
-
-    expect(Foo.count, 0);
-    expect(Bar.count, 1);
-    expect(Fizz.count, 1);
-
-    config = DebugReassembleConfig(widgetName: 'Fizz');
-    WidgetsBinding.instance.buildOwner!.reassemble(WidgetsBinding.instance.renderViewElement!, config);
-
-    expect(Foo.count, 0);
-    expect(Bar.count, 1);
-    expect(Fizz.count, 2);
-
-    config = DebugReassembleConfig(widgetName: 'NoMatch');
-    WidgetsBinding.instance.buildOwner!.reassemble(WidgetsBinding.instance.renderViewElement!, config);
-
-    expect(Foo.count, 0);
-    expect(Bar.count, 1);
-    expect(Fizz.count, 2);
-
-    config = DebugReassembleConfig();
-    WidgetsBinding.instance.buildOwner!.reassemble(WidgetsBinding.instance.renderViewElement!, config);
-
-    expect(Foo.count, 1);
-    expect(Bar.count, 2);
-    expect(Fizz.count, 3);
-
-    WidgetsBinding.instance.buildOwner!.reassemble(WidgetsBinding.instance.renderViewElement!, null);
-
-    expect(Foo.count, 2);
-    expect(Bar.count, 3);
-    expect(Fizz.count, 4);
-  });
-}
-
-class Foo extends StatefulWidget {
-  const Foo(this.child, {super.key});
-
-  final Widget child;
-  static int count = 0;
-
-  @override
-  State<Foo> createState() => _FooState();
-}
-
-class _FooState extends State<Foo> {
-  @override
-  void reassemble() {
-    Foo.count += 1;
-    super.reassemble();
-  }
-
-  @override
-  Widget build(BuildContext context) {
-    return widget.child;
-  }
-}
-
-
-class Bar extends StatefulWidget {
-  const Bar(this.child, {super.key});
-
-  final Widget child;
-  static int count = 0;
-
-  @override
-  State<Bar> createState() => _BarState();
-}
-
-class _BarState extends State<Bar> {
-  @override
-  void reassemble() {
-    Bar.count += 1;
-    super.reassemble();
-  }
-
-  @override
-  Widget build(BuildContext context) {
-    return widget.child;
-  }
-}
-
-class Fizz extends StatefulWidget {
-  const Fizz(this.child, {super.key});
-
-  final Widget child;
-  static int count = 0;
-
-  @override
-  State<Fizz> createState() => _FizzState();
-}
-
-class _FizzState extends State<Fizz> {
-  @override
-  void reassemble() {
-    Fizz.count += 1;
-    super.reassemble();
-  }
-
-  @override
-  Widget build(BuildContext context) {
-    return widget.child;
-  }
-}

packages/flutter/test/widgets/widget_inspector_test_utils.dart

@@ -59,7 +59,7 @@ class TestWidgetInspectorService extends Object with WidgetInspectorService {
     final WidgetsBinding binding = WidgetsBinding.instance;
 
     if (binding.renderViewElement != null) {
-      binding.buildOwner!.reassemble(binding.renderViewElement!, null);
+      binding.buildOwner!.reassemble(binding.renderViewElement!);
     }
   }