[go_router] ShellRoute will merge GoRouter's observers

packages/go_router/CHANGELOG.md

@@ -1,3 +1,8 @@
+## 16.2.5
+
+- `ShellRoute` will auto merge the `observers` passed into `GoRouter`.
+- Adds `mergeObservers` to `ShellRouteBase`, `ShellRoute`, `StatefulShellRoute`, `ShellRouteData.$route`.
+
 ## 16.2.4
 
 - Fix Android Cold Start deep link with empty path losing scheme and authority.

packages/go_router/lib/go_router.dart

@@ -15,6 +15,7 @@ export 'src/misc/custom_parameter.dart';
 export 'src/misc/errors.dart';
 export 'src/misc/extensions.dart';
 export 'src/misc/inherited_router.dart';
+export 'src/misc/merged_observer.dart';
 export 'src/pages/custom_transition_page.dart';
 export 'src/parser.dart';
 export 'src/route.dart';

packages/go_router/lib/src/misc/merged_observer.dart

@@ -0,0 +1,61 @@
+import 'package:flutter/widgets.dart';
+
+/// A [NavigatorObserver] that merges the observers of the current
+/// route with the observers of the previous route.
+class MergedNavigatorObserver extends NavigatorObserver {
+  /// Default constructor for the merged navigator observer.
+  MergedNavigatorObserver(this.observers);
+
+  /// The observers to be merged.
+  final List<NavigatorObserver> observers;
+
+  @override
+  void didPush(Route<dynamic> route, Route<dynamic>? previousRoute) {
+    for (final NavigatorObserver observer in observers) {
+      observer.didPush(route, previousRoute);
+    }
+  }
+
+  @override
+  void didPop(Route<dynamic> route, Route<dynamic>? previousRoute) {
+    for (final NavigatorObserver observer in observers) {
+      observer.didPop(route, previousRoute);
+    }
+  }
+
+  @override
+  void didRemove(Route<dynamic> route, Route<dynamic>? previousRoute) {
+    for (final NavigatorObserver observer in observers) {
+      observer.didRemove(route, previousRoute);
+    }
+  }
+
+  @override
+  void didReplace({Route<dynamic>? newRoute, Route<dynamic>? oldRoute}) {
+    for (final NavigatorObserver observer in observers) {
+      observer.didReplace(newRoute: newRoute, oldRoute: oldRoute);
+    }
+  }
+
+  @override
+  void didChangeTop(Route<dynamic> topRoute, Route<dynamic>? previousTopRoute) {
+    for (final NavigatorObserver observer in observers) {
+      observer.didChangeTop(topRoute, previousTopRoute);
+    }
+  }
+
+  @override
+  void didStartUserGesture(
+      Route<dynamic> route, Route<dynamic>? previousRoute) {
+    for (final NavigatorObserver observer in observers) {
+      observer.didStartUserGesture(route, previousRoute);
+    }
+  }
+
+  @override
+  void didStopUserGesture() {
+    for (final NavigatorObserver observer in observers) {
+      observer.didStopUserGesture();
+    }
+  }
+}

packages/go_router/lib/src/route.dart

@@ -13,6 +13,7 @@ import 'package:meta/meta.dart' as meta;
 
 import 'configuration.dart';
 import 'match.dart';
+import 'misc/merged_observer.dart';
 import 'path_utils.dart';
 import 'router.dart';
 import 'state.dart';
@@ -498,8 +499,20 @@ abstract class ShellRouteBase extends RouteBase {
     super.redirect,
     required super.routes,
     required super.parentNavigatorKey,
+    this.mergeObservers = true,
   }) : super._();
 
+  /// Whether to merge the observers of the shell route's parent with the
+  /// observers of the shell route.
+  ///
+  /// When `true`, the observers of the shell route's parent will be merged with
+  /// the observers of the shell route.
+  ///
+  /// Only effective for `observers` passed into `GoRouter`.
+  ///
+  /// Defaults to `false`.
+  final bool mergeObservers;
+
   static void _debugCheckSubRouteParentNavigatorKeys(
     List<RouteBase> subRoutes,
     GlobalKey<NavigatorState> navigatorKey,
@@ -577,14 +590,30 @@ class ShellRouteContext {
   final NavigatorBuilder navigatorBuilder;
 
   Widget _buildNavigatorForCurrentRoute(
+    BuildContext context,
     List<NavigatorObserver>? observers,
+    bool mergeObservers,
     String? restorationScopeId,
   ) {
+    final List<NavigatorObserver> effectiveObservers = <NavigatorObserver>[
+      ...?observers
+    ];
+
+    if (mergeObservers) {
+      final List<NavigatorObserver>? rootObservers =
+          GoRouter.maybeOf(context)?.observers;
+      if (rootObservers != null) {
+        effectiveObservers.add(MergedNavigatorObserver(
+          rootObservers,
+        ));
+      }
+    }
+
     return navigatorBuilder(
       navigatorKey,
       match,
       routeMatchList,
-      observers,
+      effectiveObservers,
       restorationScopeId,
     );
   }
@@ -691,6 +720,7 @@ class ShellRoute extends ShellRouteBase {
     super.redirect,
     this.builder,
     this.pageBuilder,
+    super.mergeObservers,
     this.observers,
     required super.routes,
     super.parentNavigatorKey,
@@ -732,7 +762,9 @@ class ShellRoute extends ShellRouteBase {
   ) {
     if (builder != null) {
       final Widget navigator = shellRouteContext._buildNavigatorForCurrentRoute(
+        context,
         observers,
+        mergeObservers,
         restorationScopeId,
       );
       return builder!(context, state, navigator);
@@ -748,7 +780,9 @@ class ShellRoute extends ShellRouteBase {
   ) {
     if (pageBuilder != null) {
       final Widget navigator = shellRouteContext._buildNavigatorForCurrentRoute(
+        context,
         observers,
+        mergeObservers,
         restorationScopeId,
       );
       return pageBuilder!(context, state, navigator);
@@ -870,6 +904,7 @@ class StatefulShellRoute extends ShellRouteBase {
     super.redirect,
     this.builder,
     this.pageBuilder,
+    super.mergeObservers,
     required this.navigatorContainerBuilder,
     super.parentNavigatorKey,
     this.restorationScopeId,
@@ -900,6 +935,7 @@ class StatefulShellRoute extends ShellRouteBase {
   /// for a complete runnable example using StatefulShellRoute.indexedStack.
   StatefulShellRoute.indexedStack({
     required List<StatefulShellBranch> branches,
+    bool mergeObservers = true,
     GoRouterRedirect? redirect,
     StatefulShellRouteBuilder? builder,
     GlobalKey<NavigatorState>? parentNavigatorKey,
@@ -911,6 +947,7 @@ class StatefulShellRoute extends ShellRouteBase {
          redirect: redirect,
          builder: builder,
          pageBuilder: pageBuilder,
+         mergeObservers: mergeObservers,
          parentNavigatorKey: parentNavigatorKey,
          restorationScopeId: restorationScopeId,
          navigatorContainerBuilder: _indexedStackContainerBuilder,
@@ -1018,6 +1055,7 @@ class StatefulShellRoute extends ShellRouteBase {
   ) => StatefulNavigationShell(
     shellRouteContext: shellRouteContext,
     router: GoRouter.of(context),
+    mergeObservers: mergeObservers,
     containerBuilder: navigatorContainerBuilder,
   );
 
@@ -1207,6 +1245,7 @@ class StatefulNavigationShell extends StatefulWidget {
     required this.shellRouteContext,
     required GoRouter router,
     required this.containerBuilder,
+    this.mergeObservers = true,
   }) : assert(shellRouteContext.route is StatefulShellRoute),
        _router = router,
        currentIndex = _indexOfBranchNavigatorKey(
@@ -1231,6 +1270,9 @@ class StatefulNavigationShell extends StatefulWidget {
   /// Corresponds to the index in the branches field of [StatefulShellRoute].
   final int currentIndex;
 
+  /// Same to [ShellRoute.mergeObservers].
+  final bool mergeObservers;
+
   /// The associated [StatefulShellRoute].
   StatefulShellRoute get route => shellRouteContext.route as StatefulShellRoute;
 
@@ -1422,7 +1464,9 @@ class StatefulNavigationShellState extends State<StatefulNavigationShell>
         previousBranchLocation != currentBranchLocation;
     if (locationChanged || !hasExistingNavigator) {
       branchState.navigator = shellRouteContext._buildNavigatorForCurrentRoute(
+        context,
         branch.observers,
+        false,
         branch.restorationScopeId,
       );
     }

packages/go_router/lib/src/route_data.dart

@@ -314,6 +314,7 @@ abstract class ShellRouteData extends RouteData {
     GlobalKey<NavigatorState>? navigatorKey,
     GlobalKey<NavigatorState>? parentNavigatorKey,
     List<RouteBase> routes = const <RouteBase>[],
+    bool mergeObservers = true,
     List<NavigatorObserver>? observers,
     String? restorationScopeId,
   }) {
@@ -342,6 +343,7 @@ abstract class ShellRouteData extends RouteData {
       parentNavigatorKey: parentNavigatorKey,
       routes: routes,
       navigatorKey: navigatorKey,
+      mergeObservers: mergeObservers,
       observers: observers,
       restorationScopeId: restorationScopeId,
       redirect: redirect,
@@ -559,7 +561,12 @@ class TypedRelativeGoRoute<T extends RelativeGoRouteData>
 @Target(<TargetKind>{TargetKind.library, TargetKind.classType})
 class TypedShellRoute<T extends ShellRouteData> extends TypedRoute<T> {
   /// Default const constructor
-  const TypedShellRoute({this.routes = const <TypedRoute<RouteData>>[]});
+  const TypedShellRoute({ this.mergeObservers = true,this.routes = const <TypedRoute<RouteData>>[]});
+
+  /// Determines whether the observers should be merged.
+  ///
+  /// See [ShellRouteBase.mergeObservers].
+  final bool mergeObservers;
 
   /// Child route definitions.
   ///
@@ -573,9 +580,15 @@ class TypedStatefulShellRoute<T extends StatefulShellRouteData>
     extends TypedRoute<T> {
   /// Default const constructor
   const TypedStatefulShellRoute({
+    this.mergeObservers = true,
     this.branches = const <TypedStatefulShellBranch<StatefulShellBranchData>>[],
   });
 
+  /// Determines whether the observers should be merged.
+  ///
+  /// See [ShellRouteBase.mergeObservers].
+  final bool mergeObservers;
+
   /// Child route definitions.
   ///
   /// See [RouteBase.routes].

packages/go_router/lib/src/router.dart

@@ -177,7 +177,7 @@ class GoRouter implements RouterConfig<RouteMatchList> {
     String? initialLocation,
     this.overridePlatformDefaultLocation = false,
     Object? initialExtra,
-    List<NavigatorObserver>? observers,
+    this.observers,
     bool debugLogDiagnostics = false,
     GlobalKey<NavigatorState>? navigatorKey,
     String? restorationScopeId,
@@ -309,6 +309,9 @@ class GoRouter implements RouterConfig<RouteMatchList> {
   @override
   late final GoRouteInformationParser routeInformationParser;
 
+  /// The navigator observers used by [GoRouter].
+  final List<NavigatorObserver>? observers;
+
   void _handleRoutingConfigChanged() {
     // Reparse is needed to update its builder
     restore(configuration.reparse(routerDelegate.currentConfiguration));

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: 16.2.4
+version: 16.2.5
 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_observers_test.dart

@@ -2,10 +2,13 @@
 // 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';
+
 void main() {
   test('ShellRoute observers test', () {
     final ShellRoute shell = ShellRoute(
@@ -25,4 +28,36 @@ void main() {
 
     expect(shell.observers!.length, 1);
   });
+
+  testWidgets('observers should be merged', (WidgetTester tester) async {
+    final HeroController observer = HeroController();
+    final List<NavigatorObserver> observers = <NavigatorObserver>[observer];
+    addTearDown(observer.dispose);
+
+    final GlobalKey<NavigatorState> navKey = GlobalKey<NavigatorState>();
+    await createRouter(
+      <RouteBase>[
+        ShellRoute(
+          navigatorKey: navKey,
+          builder: (_, __, Widget child) => child,
+          routes: <RouteBase>[
+            GoRoute(
+              path: '/',
+              parentNavigatorKey: navKey,
+              builder: (_, __) => const Text('Home'),
+            ),
+          ],
+        ),
+      ],
+      tester,
+      observers: observers,
+    );
+    await tester.pumpAndSettle();
+
+    final List<NavigatorObserver> shellRouteObservers =
+        navKey.currentState!.widget.observers;
+    final MergedNavigatorObserver mergedObservers =
+        shellRouteObservers.single as MergedNavigatorObserver;
+    expect(listEquals(observers, mergedObservers.observers), isTrue);
+  });
 }

packages/go_router/test/test_helpers.dart

@@ -176,6 +176,7 @@ Future<GoRouter> createRouter(
   GoExceptionHandler? onException,
   bool requestFocus = true,
   bool overridePlatformDefaultLocation = false,
+  List<NavigatorObserver>? observers,
 }) async {
   final GoRouter goRouter = GoRouter(
     routes: routes,
@@ -190,6 +191,7 @@ Future<GoRouter> createRouter(
     restorationScopeId: restorationScopeId,
     requestFocus: requestFocus,
     overridePlatformDefaultLocation: overridePlatformDefaultLocation,
+    observers: observers,
   );
   addTearDown(goRouter.dispose);
   await tester.pumpWidget(