Fix: DelegateTransition for cupertino sheet route (#164675)

Fix: DelegateTransition for cupertino sheet route
fixes: #163954 

## Pre-launch Checklist

- [x] I read the [Contributor Guide] and followed the process outlined
there for submitting PRs.
- [x] I read the [Tree Hygiene] wiki page, which explains my
responsibilities.
- [x] I read and followed the [Flutter Style Guide], including [Features
we expect every widget to implement].
- [x] I signed the [CLA].
- [x] I listed at least one issue that this PR fixes in the description
above.
- [x] I updated/added relevant documentation (doc comments with `///`).
- [x] I added new tests to check the change I am making, or this PR is
[test-exempt].
- [x] I followed the [breaking change policy] and added [Data Driven
Fixes] where supported.
- [x] All existing and new tests are passing.

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

@@ -1583,7 +1583,7 @@ abstract class ModalRoute<T> extends TransitionRoute<T> with LocalHistoryRoute<T
     Animation<double> secondaryAnimation,
     Widget child,
   ) {
-    if (receivedTransition == null) {
+    if (receivedTransition == null || secondaryAnimation.isDismissed) {
       return buildTransitions(context, animation, secondaryAnimation, child);
     }
 

packages/flutter/test/cupertino/sheet_test.dart

@@ -4,6 +4,7 @@
 
 import 'package:flutter/cupertino.dart';
 import 'package:flutter/material.dart';
+import 'package:flutter_localizations/flutter_localizations.dart';
 import 'package:flutter_test/flutter_test.dart';
 
 import '../widgets/navigator_utils.dart';
@@ -810,8 +811,73 @@ void main() {
     await tester.pumpAndSettle();
 
     final Finder clipRRectFinder = find.byType(ClipRRect);
-    final Rect clipRect = tester.getRect(clipRRectFinder);
-    expect(clipRect.center, equals(const Offset(400, 300)));
+    expect(clipRRectFinder, findsNothing);
+  });
+
+  testWidgets('Sheet transition does not interfere after popping', (WidgetTester tester) async {
+    final GlobalKey homeKey = GlobalKey();
+    final GlobalKey sheetKey = GlobalKey();
+    final GlobalKey popupMenuButtonKey = GlobalKey();
+
+    await tester.pumpWidget(
+      CupertinoApp(
+        localizationsDelegates: const <LocalizationsDelegate<dynamic>>[
+          GlobalMaterialLocalizations.delegate,
+          GlobalWidgetsLocalizations.delegate,
+          GlobalCupertinoLocalizations.delegate,
+        ],
+        home: CupertinoPageScaffold(
+          key: homeKey,
+          child: CupertinoListTile(
+            onTap: () {
+              showCupertinoSheet<void>(
+                context: homeKey.currentContext!,
+                pageBuilder: (BuildContext context) {
+                  return CupertinoPageScaffold(
+                    key: sheetKey,
+                    child: const Center(child: Text('Page 2')),
+                  );
+                },
+              );
+            },
+            title: const Text('ListItem 0'),
+            trailing: Material(
+              type: MaterialType.transparency,
+              child: PopupMenuButton<int>(
+                key: popupMenuButtonKey,
+                itemBuilder: (BuildContext context) {
+                  return <PopupMenuEntry<int>>[
+                    const PopupMenuItem<int>(child: Text('Item 0')),
+                    const PopupMenuItem<int>(child: Text('Item 1')),
+                  ];
+                },
+              ),
+            ),
+          ),
+        ),
+      ),
+    );
+
+    await tester.tap(find.text('ListItem 0'));
+    await tester.pumpAndSettle();
+
+    expect(find.text('Page 2'), findsOneWidget);
+
+    final TestGesture gesture = await tester.startGesture(const Offset(100, 200));
+    await gesture.moveBy(const Offset(0, 350));
+    await tester.pump();
+
+    await gesture.up();
+    await tester.pumpAndSettle();
+
+    expect(find.text('Page 2'), findsNothing);
+    expect(find.text('ListItem 0'), findsOneWidget);
+
+    await tester.tap(find.byKey(popupMenuButtonKey));
+    await tester.pumpAndSettle();
+
+    expect(find.text('Item 0'), findsOneWidget);
+    expect(tester.takeException(), isNull);
   });
 
   group('drag dismiss gesture', () {

packages/flutter/test/widgets/routes_test.dart

@@ -766,6 +766,52 @@ void main() {
       expect(secondaryAnimationPageOne.parent, kAlwaysDismissedAnimation);
     });
 
+    testWidgets(
+      'delegated transitions are removed when secondary animation is dismissed and next route is removed',
+      (WidgetTester tester) async {
+        final GlobalKey<NavigatorState> navigator = GlobalKey<NavigatorState>();
+        await tester.pumpWidget(
+          MaterialApp(
+            navigatorKey: navigator,
+            theme: ThemeData(
+              pageTransitionsTheme: const PageTransitionsTheme(
+                builders: <TargetPlatform, PageTransitionsBuilder>{
+                  TargetPlatform.android: CupertinoPageTransitionsBuilder(),
+                },
+              ),
+            ),
+            home: const Text('home'),
+          ),
+        );
+
+        // Push first page with custom transition builder.
+        final Route<void> firstRoute = CupertinoSheetRoute<void>(
+          builder: (_) {
+            return const Text('Page One');
+          },
+        );
+
+        navigator.currentState!.push(firstRoute);
+        await tester.pumpAndSettle();
+
+        expect(find.text('Page One'), findsOneWidget);
+        final Finder cupertinoSheetDelegatedTransitionFinder = find.ancestor(
+          of: find.ancestor(of: find.byType(ClipRRect), matching: find.byType(AnimatedBuilder)),
+          matching: find.byType(ScaleTransition),
+        );
+        expect(cupertinoSheetDelegatedTransitionFinder, findsOneWidget);
+
+        navigator.currentState!.pop();
+        await tester.pumpAndSettle();
+
+        // Verify home is still visible without transitions.
+        expect(find.text('home'), findsOneWidget);
+
+        // Verify the delegated transition is removed.
+        expect(cupertinoSheetDelegatedTransitionFinder, findsNothing);
+      },
+    );
+
     testWidgets('secondary animation is kDismissed after train hopping finishes and pop', (
       WidgetTester tester,
     ) async {