fixes SearchAnchor leak (#147652)

Author: Dimilkalathiya

packages/flutter/lib/src/material/search_anchor.dart

@@ -518,6 +518,8 @@ class _SearchViewRoute extends PopupRoute<_SearchViewRoute> {
   final CapturedThemes capturedThemes;
   final TextInputAction? textInputAction;
   final TextInputType? keyboardType;
+  CurvedAnimation? curvedAnimation;
+  CurvedAnimation? viewFadeOnIntervalCurve;
 
   @override
   Color? get barrierColor => Colors.transparent;
@@ -561,6 +563,13 @@ class _SearchViewRoute extends PopupRoute<_SearchViewRoute> {
     return super.didPop(result);
   }
 
+  @override
+  void dispose() {
+    curvedAnimation?.dispose();
+    viewFadeOnIntervalCurve?.dispose();
+    super.dispose();
+  }
+
   void updateViewConfig(BuildContext context) {
     viewDefaults = _SearchViewDefaultsM3(context, isFullScreen: showFullScreenView);
     viewTheme = SearchViewTheme.of(context);
@@ -620,23 +629,25 @@ class _SearchViewRoute extends PopupRoute<_SearchViewRoute> {
       child: AnimatedBuilder(
         animation: animation,
         builder: (BuildContext context, Widget? child) {
-          final Animation<double> curvedAnimation = CurvedAnimation(
+          curvedAnimation ??= CurvedAnimation(
             parent: animation,
             curve: Curves.easeInOutCubicEmphasized,
             reverseCurve: Curves.easeInOutCubicEmphasized.flipped,
           );
 
-          final Rect viewRect = _rectTween.evaluate(curvedAnimation)!;
+          final Rect viewRect = _rectTween.evaluate(curvedAnimation!)!;
           final double topPadding = showFullScreenView
-            ? lerpDouble(0.0, MediaQuery.paddingOf(context).top, curvedAnimation.value)!
+            ? lerpDouble(0.0, MediaQuery.paddingOf(context).top, curvedAnimation!.value)!
             : 0.0;
 
+          viewFadeOnIntervalCurve ??= CurvedAnimation(
+            parent: animation,
+            curve: _kViewFadeOnInterval,
+            reverseCurve: _kViewFadeOnInterval.flipped,
+          );
+
           return FadeTransition(
-            opacity: CurvedAnimation(
-              parent: animation,
-              curve: _kViewFadeOnInterval,
-              reverseCurve: _kViewFadeOnInterval.flipped,
-            ),
+            opacity: viewFadeOnIntervalCurve!,
             child: capturedThemes.wrap(
               _ViewContent(
                 viewOnChanged: viewOnChanged,
@@ -654,7 +665,7 @@ class _SearchViewRoute extends PopupRoute<_SearchViewRoute> {
                 viewHeaderHintStyle: viewHeaderHintStyle,
                 dividerColor: dividerColor,
                 showFullScreenView: showFullScreenView,
-                animation: curvedAnimation,
+                animation: curvedAnimation!,
                 topPadding: topPadding,
                 viewMaxWidth: _rectTween.end!.width,
                 viewRect: viewRect,
@@ -738,6 +749,9 @@ class _ViewContent extends StatefulWidget {
 class _ViewContentState extends State<_ViewContent> {
   Size? _screenSize;
   late Rect _viewRect;
+  late CurvedAnimation viewIconsFadeCurve;
+  late CurvedAnimation viewDividerFadeCurve;
+  late CurvedAnimation viewListFadeOnIntervalCurve;
   late final SearchController _controller;
   Iterable<Widget> result = <Widget>[];
   String? searchValue;
@@ -749,6 +763,7 @@ class _ViewContentState extends State<_ViewContent> {
     _viewRect = widget.viewRect;
     _controller = widget.searchController;
     _controller.addListener(updateSuggestions);
+    _setupAnimations();
   }
 
   @override
@@ -787,11 +802,36 @@ class _ViewContentState extends State<_ViewContent> {
   @override
   void dispose() {
     _controller.removeListener(updateSuggestions);
+    _disposeAnimations();
     _timer?.cancel();
     _timer = null;
     super.dispose();
   }
 
+  void _setupAnimations() {
+    viewIconsFadeCurve = CurvedAnimation(
+      parent: widget.animation,
+      curve: _kViewIconsFadeOnInterval,
+      reverseCurve: _kViewIconsFadeOnInterval.flipped,
+    );
+    viewDividerFadeCurve = CurvedAnimation(
+      parent: widget.animation,
+      curve: _kViewDividerFadeOnInterval,
+      reverseCurve: _kViewFadeOnInterval.flipped,
+    );
+      viewListFadeOnIntervalCurve = CurvedAnimation(
+      parent: widget.animation,
+      curve: _kViewListFadeOnInterval,
+      reverseCurve: _kViewListFadeOnInterval.flipped,
+    );
+  }
+
+  void _disposeAnimations() {
+    viewIconsFadeCurve.dispose();
+    viewDividerFadeCurve.dispose();
+    viewListFadeOnIntervalCurve.dispose();
+  }
+
   Widget viewBuilder(Iterable<Widget> suggestions) {
     if (widget.viewBuilder == null) {
       return MediaQuery.removePadding(
@@ -900,11 +940,7 @@ class _ViewContentState extends State<_ViewContent> {
                 maxWidth: math.min(widget.viewMaxWidth, _screenSize!.width),
                 minWidth: 0,
                 child: FadeTransition(
-                  opacity: CurvedAnimation(
-                    parent: widget.animation,
-                    curve: _kViewIconsFadeOnInterval,
-                    reverseCurve: _kViewIconsFadeOnInterval.flipped,
-                  ),
+                  opacity: viewIconsFadeCurve,
                   child: Column(
                     crossAxisAlignment: CrossAxisAlignment.stretch,
                     children: <Widget>[
@@ -937,19 +973,11 @@ class _ViewContentState extends State<_ViewContent> {
                         ),
                       ),
                       FadeTransition(
-                        opacity: CurvedAnimation(
-                          parent: widget.animation,
-                          curve: _kViewDividerFadeOnInterval,
-                          reverseCurve: _kViewFadeOnInterval.flipped,
-                        ),
+                        opacity: viewDividerFadeCurve,
                         child: viewDivider),
                       Expanded(
                         child: FadeTransition(
-                          opacity: CurvedAnimation(
-                            parent: widget.animation,
-                            curve: _kViewListFadeOnInterval,
-                            reverseCurve: _kViewListFadeOnInterval.flipped,
-                          ),
+                          opacity: viewListFadeOnIntervalCurve,
                           child: viewBuilder(result),
                         ),
                       ),

packages/flutter/test/material/search_anchor_test.dart

@@ -9,6 +9,7 @@ import 'package:flutter/gestures.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter/rendering.dart';
 import 'package:flutter_test/flutter_test.dart';
+import 'package:leak_tracker_flutter_testing/leak_tracker_flutter_testing.dart';
 
 import '../widgets/semantics_tester.dart';
 
@@ -898,7 +899,10 @@ void main() {
     expect(textField.textCapitalization, TextCapitalization.none);
   });
 
-  testWidgets('SearchAnchor respects viewOnChanged and viewOnSubmitted properties', (WidgetTester tester) async {
+  testWidgets('SearchAnchor respects viewOnChanged and viewOnSubmitted properties',
+  // TODO(polina-c): remove when fixed https://github.com/flutter/flutter/issues/145600 [leak-tracking-opt-in]
+  experimentalLeakTesting: LeakTesting.settings.withTracked(classes: const <String>['CurvedAnimation']),
+  (WidgetTester tester) async {
     final SearchController controller = SearchController();
     addTearDown(controller.dispose);
     int onChangedCalled = 0;