[go_router] Fix ShellRoutes break iOS swipe back navigation

packages/go_router/CHANGELOG.md

@@ -1,3 +1,7 @@
+## 16.2.3
+
+- Fixes an issue where iOS back gesture pops entire ShellRoute instead of the active sub-route.
+
 ## 16.2.2
 
 - Fixes broken links in readme.

packages/go_router/lib/src/builder.dart

@@ -293,20 +293,27 @@ class _CustomNavigatorState extends State<_CustomNavigator> {
         List<NavigatorObserver>? observers,
         String? restorationScopeId,
       ) {
-        return _CustomNavigator(
-          // The state needs to persist across rebuild.
-          key: GlobalObjectKey(navigatorKey.hashCode),
-          navigatorRestorationId: restorationScopeId,
-          navigatorKey: navigatorKey,
-          matches: match.matches,
-          matchList: matchList,
-          configuration: widget.configuration,
-          observers: observers ?? const <NavigatorObserver>[],
-          onPopPageWithRouteMatch: widget.onPopPageWithRouteMatch,
-          // This is used to recursively build pages under this shell route.
-          errorBuilder: widget.errorBuilder,
-          errorPageBuilder: widget.errorPageBuilder,
-          requestFocus: widget.requestFocus,
+        return PopScope(
+          // Prevent ShellRoute from being popped, for example
+          // by an iOS back gesture, when the route has active sub-routes.
+          // TODO(LukasMirbt): Remove when minimum flutter version includes
+          // https://github.com/flutter/flutter/pull/152330.
+          canPop: match.matches.length == 1,
+          child: _CustomNavigator(
+            // The state needs to persist across rebuild.
+            key: GlobalObjectKey(navigatorKey.hashCode),
+            navigatorRestorationId: restorationScopeId,
+            navigatorKey: navigatorKey,
+            matches: match.matches,
+            matchList: matchList,
+            configuration: widget.configuration,
+            observers: observers ?? const <NavigatorObserver>[],
+            onPopPageWithRouteMatch: widget.onPopPageWithRouteMatch,
+            // This is used to recursively build pages under this shell route.
+            errorBuilder: widget.errorBuilder,
+            errorPageBuilder: widget.errorPageBuilder,
+            requestFocus: widget.requestFocus,
+          ),
         );
       },
     );

packages/go_router/pubspec.yaml

@@ -1,7 +1,7 @@
 name: go_router
 description: A declarative router for Flutter based on Navigation 2 supporting
   deep linking, data-driven routes and more
-version: 16.2.2
+version: 16.2.3
 repository: https://github.com/flutter/packages/tree/main/packages/go_router
 issue_tracker: https://github.com/flutter/flutter/issues?q=is%3Aissue+is%3Aopen+label%3A%22p%3A+go_router%22
 

packages/go_router/test/shell_route_system_back_test.dart

@@ -0,0 +1,165 @@
+// Copyright 2013 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/material.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:go_router/go_router.dart';
+
+import 'test_helpers.dart';
+
+// Regression test for https://github.com/flutter/flutter/issues/120353
+void main() {
+  group('iOS back gesture inside a ShellRoute', () {
+    testWidgets('pops the top sub-route '
+        'when there is an active sub-route', (WidgetTester tester) async {
+      debugDefaultTargetPlatformOverride = TargetPlatform.iOS;
+
+      await tester.pumpWidget(const _TestApp());
+      expect(find.text('Home'), findsOneWidget);
+
+      await tester.tap(find.byType(FilledButton));
+      await tester.pumpAndSettle();
+      expect(find.text('Post'), findsOneWidget);
+
+      await tester.tap(find.byType(FilledButton));
+      await tester.pumpAndSettle();
+      expect(find.text('Comment'), findsOneWidget);
+
+      await simulateIosBackGesture(tester);
+      await tester.pumpAndSettle();
+      expect(find.text('Post'), findsOneWidget);
+
+      debugDefaultTargetPlatformOverride = null;
+    });
+
+    testWidgets('pops ShellRoute '
+        'when there are no active sub-routes', (WidgetTester tester) async {
+      debugDefaultTargetPlatformOverride = TargetPlatform.iOS;
+
+      await tester.pumpWidget(const _TestApp());
+      expect(find.text('Home'), findsOneWidget);
+
+      await tester.tap(find.byType(FilledButton));
+      await tester.pumpAndSettle();
+      expect(find.text('Post'), findsOneWidget);
+
+      await simulateIosBackGesture(tester);
+      await tester.pumpAndSettle();
+      expect(find.text('Home'), findsOneWidget);
+
+      debugDefaultTargetPlatformOverride = null;
+    });
+  });
+
+  group('Android back button inside a ShellRoute', () {
+    testWidgets('pops the top sub-route '
+        'when there is an active sub-route', (WidgetTester tester) async {
+      await tester.pumpWidget(const _TestApp());
+      expect(find.text('Home'), findsOneWidget);
+
+      await tester.tap(find.byType(FilledButton));
+      await tester.pumpAndSettle();
+      expect(find.text('Post'), findsOneWidget);
+
+      await tester.tap(find.byType(FilledButton));
+      await tester.pumpAndSettle();
+      expect(find.text('Comment'), findsOneWidget);
+
+      await simulateAndroidBackButton(tester);
+      await tester.pumpAndSettle();
+      expect(find.text('Post'), findsOneWidget);
+    });
+
+    testWidgets('pops ShellRoute '
+        'when there are no active sub-routes', (WidgetTester tester) async {
+      await tester.pumpWidget(const _TestApp());
+      expect(find.text('Home'), findsOneWidget);
+
+      await tester.tap(find.byType(FilledButton));
+      await tester.pumpAndSettle();
+      expect(find.text('Post'), findsOneWidget);
+
+      await simulateAndroidBackButton(tester);
+      await tester.pumpAndSettle();
+      expect(find.text('Home'), findsOneWidget);
+    });
+  });
+}
+
+class _TestApp extends StatefulWidget {
+  const _TestApp();
+
+  @override
+  State<_TestApp> createState() => _TestAppState();
+}
+
+class _TestAppState extends State<_TestApp> {
+  final GoRouter _router = GoRouter(
+    routes: <GoRoute>[
+      GoRoute(
+        path: '/',
+        builder: (BuildContext context, GoRouterState state) {
+          return Scaffold(
+            appBar: AppBar(title: const Text('Home')),
+            body: Center(
+              child: FilledButton(
+                onPressed: () {
+                  GoRouter.of(context).go('/post');
+                },
+                child: const Text('Go to Post'),
+              ),
+            ),
+          );
+        },
+        routes: <RouteBase>[
+          ShellRoute(
+            builder: (BuildContext context, GoRouterState state, Widget child) {
+              return child;
+            },
+            routes: <GoRoute>[
+              GoRoute(
+                path: '/post',
+                builder: (BuildContext context, GoRouterState state) {
+                  return Scaffold(
+                    appBar: AppBar(title: const Text('Post')),
+                    body: Center(
+                      child: FilledButton(
+                        onPressed: () {
+                          GoRouter.of(context).go('/post/comment');
+                        },
+                        child: const Text('Comment'),
+                      ),
+                    ),
+                  );
+                },
+                routes: <GoRoute>[
+                  GoRoute(
+                    path: 'comment',
+                    builder: (BuildContext context, GoRouterState state) {
+                      return Scaffold(
+                        appBar: AppBar(title: const Text('Comment')),
+                      );
+                    },
+                  ),
+                ],
+              ),
+            ],
+          ),
+        ],
+      ),
+    ],
+  );
+
+  @override
+  void dispose() {
+    _router.dispose();
+    super.dispose();
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    return MaterialApp.router(routerConfig: _router);
+  }
+}