Fix StatefulShellRoute PopScope behavior to respect back button (#181945)

Author: chunhtai

packages/go_router/lib/src/delegate.dart

@@ -124,7 +124,6 @@ class GoRouterDelegate extends RouterDelegate<RouteMatchList>
     while (walker is ShellRouteMatch) {
       final NavigatorState potentialCandidate =
           walker.navigatorKey.currentState!;
-
       final ModalRoute<dynamic>? modalRoute = ModalRoute.of(
         potentialCandidate.context,
       );

packages/go_router/lib/src/route.dart

@@ -16,6 +16,7 @@ import 'match.dart';
 import 'path_utils.dart';
 import 'router.dart';
 import 'state.dart';
+import 'delegate.dart';
 
 /// The page builder for [GoRoute].
 typedef GoRouterPageBuilder =
@@ -1541,7 +1542,15 @@ class StatefulNavigationShellState extends State<StatefulNavigationShell>
             )
             .toList();
 
-    return widget.containerBuilder(context, widget, children);
+    return PopScope(
+      canPop: widget.currentIndex == 0,
+      onPopInvokedWithResult: (bool didPop, Object? result) {
+        if (!didPop && widget.currentIndex != 0) {
+          goBranch(0);
+        }
+      },
+      child: widget.containerBuilder(context, widget, children),
+    );
   }
 }
 

packages/go_router/pending_changelogs/change_2026_04_03_1775255636284.yaml

@@ -0,0 +1,3 @@
+changelog: |
+  - Fix StatefulShellRoute PopScope behavior to orchestrate back button pops to the root branch when inner navigators cannot pop.
+version: patch

packages/go_router/test/shell_route_pop_scope_test.dart

@@ -0,0 +1,115 @@
+// Copyright 2013 The Flutter Authors
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'package:flutter/material.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:go_router/go_router.dart';
+
+import 'test_helpers.dart';
+
+void main() {
+  testWidgets(
+    'PopScope in StatefulShellRoute branch works on subsequent visits',
+    (WidgetTester tester) async {
+      int tabBPopCount = 0;
+
+      final routes = <RouteBase>[
+        StatefulShellRoute.indexedStack(
+          builder:
+              (
+                BuildContext context,
+                GoRouterState state,
+                StatefulNavigationShell navigationShell,
+              ) {
+                return Scaffold(
+                  body: navigationShell,
+                  bottomNavigationBar: BottomNavigationBar(
+                    currentIndex: navigationShell.currentIndex,
+                    onTap: (int index) => navigationShell.goBranch(index),
+                    items: const <BottomNavigationBarItem>[
+                      BottomNavigationBarItem(
+                        icon: Icon(Icons.home),
+                        label: 'A',
+                      ),
+                      BottomNavigationBarItem(
+                        icon: Icon(Icons.business),
+                        label: 'B',
+                      ),
+                    ],
+                  ),
+                );
+              },
+          branches: <StatefulShellBranch>[
+            StatefulShellBranch(
+              routes: <RouteBase>[
+                GoRoute(
+                  path: '/tabA',
+                  builder: (BuildContext context, GoRouterState state) =>
+                      const DummyScreen(key: ValueKey<String>('tabA')),
+                ),
+              ],
+            ),
+            StatefulShellBranch(
+              routes: <RouteBase>[
+                GoRoute(
+                  path: '/tabB',
+                  builder: (BuildContext context, GoRouterState state) {
+                    return PopScope(
+                      canPop: false,
+                      onPopInvokedWithResult: (bool didPop, Object? result) {
+                        tabBPopCount++;
+                        if (!didPop) {
+                          context.go('/tabA');
+                        }
+                      },
+                      child: const DummyScreen(key: ValueKey<String>('tabB')),
+                    );
+                  },
+                ),
+              ],
+            ),
+          ],
+        ),
+      ];
+
+      final GoRouter router = await createRouter(
+        routes,
+        tester,
+        initialLocation: '/tabA',
+      );
+
+      // 1. Visit Tab A
+      expect(find.byKey(const ValueKey<String>('tabA')), findsOneWidget);
+      expect(find.byKey(const ValueKey<String>('tabB')), findsNothing);
+
+      // 2. Switch to Tab B
+      router.go('/tabB');
+      await tester.pumpAndSettle();
+      expect(find.byKey(const ValueKey<String>('tabB')), findsOneWidget);
+
+      // 3. Press back button on Tab B (First Visit)
+      await simulateAndroidBackButton(tester);
+      await tester.pumpAndSettle();
+
+      // Should have switched back to Tab A
+      expect(find.byKey(const ValueKey<String>('tabA')), findsOneWidget);
+      expect(tabBPopCount, 1);
+
+      // 4. Switch to Tab B again (Second Visit)
+      router.go('/tabB');
+      await tester.pumpAndSettle();
+      expect(find.byKey(const ValueKey<String>('tabB')), findsOneWidget);
+
+      // 5. Press back button on Tab B (Second Visit)
+      await simulateAndroidBackButton(tester);
+      await tester.pumpAndSettle();
+
+      // Verify that the PopScope was triggered again
+      expect(tabBPopCount, 2);
+
+      // Should have switched back to Tab A again
+      expect(find.byKey(const ValueKey<String>('tabA')), findsOneWidget);
+    },
+  );
+}