Fix the showBottomSheet controller leaking (#87775)

* Fix the showBottomSheet controller leaking

* codereview feedback

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

@@ -2690,6 +2690,7 @@ class ScaffoldState extends State<Scaffold> with TickerProviderStateMixin, Resto
     ShapeBorder? shape,
     Clip? clipBehavior,
     BoxConstraints? constraints,
+    bool shouldDisposeAnimationController = true,
   }) {
     assert(() {
       if (widget.bottomSheet != null && isPersistent && _currentBottomSheet != null) {
@@ -2757,6 +2758,11 @@ class ScaffoldState extends State<Scaffold> with TickerProviderStateMixin, Resto
           });
         }
       },
+      onDispose: () {
+        if (shouldDisposeAnimationController) {
+          animationController.dispose();
+        }
+      },
       builder: builder,
       isPersistent: isPersistent,
       backgroundColor: backgroundColor,
@@ -2894,6 +2900,7 @@ class ScaffoldState extends State<Scaffold> with TickerProviderStateMixin, Resto
         shape: shape,
         clipBehavior: clipBehavior,
         constraints: constraints,
+        shouldDisposeAnimationController: transitionAnimationController == null,
       );
     });
     return _currentBottomSheet! as PersistentBottomSheetController<T>;
@@ -3069,12 +3076,6 @@ class ScaffoldState extends State<Scaffold> with TickerProviderStateMixin, Resto
     _snackBarTimer = null;
 
     _geometryNotifier.dispose();
-    for (final _StandardBottomSheet bottomSheet in _dismissedBottomSheets) {
-      bottomSheet.animationController.dispose();
-    }
-    if (_currentBottomSheet != null) {
-      _currentBottomSheet!._widget.animationController.dispose();
-    }
     _floatingActionButtonMoveController.dispose();
     _floatingActionButtonVisibilityController.dispose();
     _scaffoldMessenger?._unregister(this);
@@ -3587,12 +3588,14 @@ class _StandardBottomSheet extends StatefulWidget {
     this.shape,
     this.clipBehavior,
     this.constraints,
+    this.onDispose,
   }) : super(key: key);
 
   final AnimationController animationController; // we control it, but it must be disposed by whoever created it.
   final bool enableDrag;
   final VoidCallback? onClosing;
   final VoidCallback? onDismissed;
+  final VoidCallback? onDispose;
   final WidgetBuilder builder;
   final bool isPersistent;
   final Color? backgroundColor;
@@ -3619,6 +3622,12 @@ class _StandardBottomSheetState extends State<_StandardBottomSheet> {
     widget.animationController.addStatusListener(_handleStatusChange);
   }
 
+  @override
+  void dispose() {
+    widget.onDispose?.call();
+    super.dispose();
+  }
+
   @override
   void didUpdateWidget(_StandardBottomSheet oldWidget) {
     super.didUpdateWidget(oldWidget);

packages/flutter/test/material/bottom_sheet_test.dart

@@ -895,6 +895,106 @@ void main() {
     expect(find.text('BottomSheet'), findsNothing);
   });
 
+  // Regression test for https://github.com/flutter/flutter/issues/87708
+  testWidgets('Each of the internal animation controllers should be disposed by the framework.', (WidgetTester tester) async {
+    final GlobalKey<ScaffoldState> scaffoldKey = GlobalKey();
+    await tester.pumpWidget(MaterialApp(
+      home: Scaffold(
+        key: scaffoldKey,
+        body: const Center(child: Text('body')),
+      ),
+    ));
+
+    scaffoldKey.currentState!.showBottomSheet<void>((_) {
+      return Builder(
+        builder: (BuildContext context) {
+          return Container(height: 200.0);
+        },
+      );
+    });
+
+    await tester.pump();
+    expect(find.byType(BottomSheet), findsOneWidget);
+
+    // The first sheet's animation is still running.
+
+    // Trigger the second sheet will remove the first sheet from tree.
+    scaffoldKey.currentState!.showBottomSheet<void>((_) {
+      return Builder(
+        builder: (BuildContext context) {
+          return Container(height: 200.0);
+        },
+      );
+    });
+    await tester.pump();
+    expect(find.byType(BottomSheet), findsOneWidget);
+
+    // Remove the Scaffold from the tree.
+    await tester.pumpWidget(const SizedBox.shrink());
+
+    // If the internal animation controller do not dispose will throw
+    // FlutterError:<ScaffoldState#1981a(tickers: tracking 1 ticker) was disposed with an active
+    // Ticker.
+    expect(tester.takeException(), isNull);
+  });
+
+  // Regression test for https://github.com/flutter/flutter/issues/87708
+  testWidgets('The framework does not dispose of the transitionAnimationController provided by user.', (WidgetTester tester) async {
+    const Key tapTarget = Key('tap-target');
+    const Key tapTargetToClose = Key('tap-target-to-close');
+    final AnimationController controller = AnimationController(
+      vsync: const TestVSync(),
+      duration: const Duration(seconds: 2),
+      reverseDuration: const Duration(seconds: 2),
+    );
+    await tester.pumpWidget(MaterialApp(
+      home: Scaffold(
+        body: Builder(
+          builder: (BuildContext context) {
+            return GestureDetector(
+              key: tapTarget,
+              onTap: () {
+                showBottomSheet<void>(
+                  context: context,
+                  transitionAnimationController: controller,
+                  builder: (BuildContext context) {
+                    return MaterialButton(
+                      onPressed: () => Navigator.pop(context),
+                      key: tapTargetToClose,
+                      child: const Text('BottomSheet'),
+                    );
+                  },
+                );
+              },
+              behavior: HitTestBehavior.opaque,
+              child: const SizedBox(
+                height: 100.0,
+                width: 100.0,
+              ),
+            );
+          },
+        ),
+      ),
+    ));
+
+    expect(find.text('BottomSheet'), findsNothing);
+
+    await tester.tap(find.byKey(tapTarget)); // Open the sheet.
+    await tester.pumpAndSettle(); // Finish the animation.
+    expect(find.text('BottomSheet'), findsOneWidget);
+
+    // Tapping button on the bottom sheet to dismiss it.
+    await tester.tap(find.byKey(tapTargetToClose)); // Closing the sheet.
+    await tester.pumpAndSettle(); // Finish the animation.
+    expect(find.text('BottomSheet'), findsNothing);
+
+    await tester.pumpWidget(const SizedBox.shrink());
+    controller.dispose();
+
+    // Double dispose will throw.
+    expect(tester.takeException(), isNull);
+  });
+
   group('constraints', () {
 
     testWidgets('No constraints by default for bottomSheet property', (WidgetTester tester) async {