[go_router] feat: access GoRouter.of from redirect methods

packages/go_router/CHANGELOG.md

@@ -1,3 +1,8 @@
+## 16.0.1
+
+- Fixes `GoRouter.of(context)` access inside redirect callbacks by providing router access through Zone-based context tracking.
+- Adds support for using context extension methods (e.g., `context.namedLocation()`, `context.go()`) within redirect callbacks.
+
 ## 16.0.0
 
 - **BREAKING CHANGE**

packages/go_router/lib/src/configuration.dart

@@ -10,6 +10,7 @@ import 'package:flutter/widgets.dart';
 
 import 'logging.dart';
 import 'match.dart';
+import 'misc/constants.dart';
 import 'misc/errors.dart';
 import 'path_utils.dart';
 import 'route.dart';
@@ -29,6 +30,7 @@ class RouteConfiguration {
     this._routingConfig, {
     required this.navigatorKey,
     this.extraCodec,
+    this.router,
   }) {
     _onRoutingTableChanged();
     _routingConfig.addListener(_onRoutingTableChanged);
@@ -248,6 +250,11 @@ class RouteConfiguration {
   ///    example.
   final Codec<Object?, Object?>? extraCodec;
 
+  /// The GoRouter instance that owns this configuration.
+  ///
+  /// This is used to provide access to the router during redirects.
+  final GoRouter? router;
+
   final Map<String, _NamedPath> _nameToPath = <String, _NamedPath>{};
 
   /// Looks up the url location by a [GoRoute]'s name.
@@ -416,10 +423,12 @@ class RouteConfiguration {
 
       redirectHistory.add(prevMatchList);
       // Check for top-level redirect
-      final FutureOr<String?> topRedirectResult = _routingConfig.value.redirect(
-        context,
-        buildTopLevelGoRouterState(prevMatchList),
-      );
+      final FutureOr<String?> topRedirectResult = _runInRouterZone(() {
+        return _routingConfig.value.redirect(
+          context,
+          buildTopLevelGoRouterState(prevMatchList),
+        );
+      });
 
       if (topRedirectResult is String?) {
         return processTopLevelRedirect(topRedirectResult);
@@ -448,10 +457,12 @@ class RouteConfiguration {
         _getRouteLevelRedirect(
             context, matchList, routeMatches, currentCheckIndex + 1);
     final RouteBase route = match.route;
-    final FutureOr<String?> routeRedirectResult = route.redirect!.call(
-      context,
-      match.buildState(this, matchList),
-    );
+    final FutureOr<String?> routeRedirectResult = _runInRouterZone(() {
+      return route.redirect!.call(
+        context,
+        match.buildState(this, matchList),
+      );
+    });
     if (routeRedirectResult is String?) {
       return processRouteRedirect(routeRedirectResult);
     }
@@ -508,6 +519,34 @@ class RouteConfiguration {
         .join(' => ');
   }
 
+  /// Runs the given function in a Zone with the router context for redirects.
+  T _runInRouterZone<T>(T Function() callback) {
+    if (router == null) {
+      return callback();
+    }
+
+    return runZonedGuarded<T>(
+      callback,
+      (Object error, StackTrace stackTrace) {
+        // Handle errors by routing them to GoRouter's error handling mechanisms
+        if (error is GoException) {
+          // For GoException, we can let it propagate as it's already handled
+          // by the existing error handling in redirect methods
+          throw error;
+        } else {
+          // For other errors, we should route them to the router's error handling
+          // This will be handled by GoRouter.onException or error builders
+          log('Error in router zone: $error');
+          // Convert the error to a GoException for proper error handling
+          throw GoException('error in router zone: $error');
+        }
+      },
+      zoneValues: <Object?, Object?>{
+        currentRouterKey: router,
+      },
+    )!;
+  }
+
   /// Get the location for the provided route.
   ///
   /// Builds the absolute path for the route, by concatenating the paths of the

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

@@ -0,0 +1,5 @@
+import 'package:meta/meta.dart';
+
+/// Symbol used as a Zone key to track the current GoRouter during redirects.
+@internal
+const Symbol currentRouterKey = #goRouterRedirectContext;

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

@@ -10,8 +10,6 @@ import '../router.dart';
 /// context.go('/');
 extension GoRouterHelper on BuildContext {
   /// Get a location from route name and parameters.
-  ///
-  /// This method can't be called during redirects.
   String namedLocation(
     String name, {
     Map<String, String> pathParameters = const <String, String>{},

packages/go_router/lib/src/router.dart

@@ -13,6 +13,7 @@ import 'delegate.dart';
 import 'information_provider.dart';
 import 'logging.dart';
 import 'match.dart';
+import 'misc/constants.dart';
 import 'misc/inherited_router.dart';
 import 'parser.dart';
 import 'route.dart';
@@ -206,6 +207,7 @@ class GoRouter implements RouterConfig<RouteMatchList> {
       _routingConfig,
       navigatorKey: navigatorKey,
       extraCodec: extraCodec,
+      router: this,
     );
 
     final ParserExceptionHandler? parserExceptionHandler;
@@ -518,22 +520,26 @@ class GoRouter implements RouterConfig<RouteMatchList> {
   }
 
   /// Find the current GoRouter in the widget tree.
-  ///
-  /// This method throws when it is called during redirects.
   static GoRouter of(BuildContext context) {
-    final GoRouter? inherited = maybeOf(context);
-    assert(inherited != null, 'No GoRouter found in context');
-    return inherited!;
+    final GoRouter? router = maybeOf(context);
+    if (router == null) {
+      throw FlutterError('No GoRouter found in context');
+    }
+    return router;
   }
 
   /// The current GoRouter in the widget tree, if any.
-  ///
-  /// This method returns null when it is called during redirects.
   static GoRouter? maybeOf(BuildContext context) {
     final InheritedGoRouter? inherited = context
         .getElementForInheritedWidgetOfExactType<InheritedGoRouter>()
         ?.widget as InheritedGoRouter?;
-    return inherited?.goRouter;
+
+    if (inherited != null) {
+      return inherited.goRouter;
+    }
+
+    // Check if we're in a redirect context
+    return Zone.current[currentRouterKey] as GoRouter?;
   }
 
   /// Disposes resource created by this object.

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: 16.0.0
+version: 16.0.1
 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/go_router_test.dart

@@ -2238,6 +2238,61 @@ void main() {
       expect(redirected, isTrue);
     });
 
+    testWidgets('GoRouter.of(context) should work in redirects',
+        (WidgetTester tester) async {
+      GoRouter? capturedRouter;
+      final List<GoRoute> routes = <GoRoute>[
+        GoRoute(
+          path: '/',
+          builder: (BuildContext context, GoRouterState state) =>
+              const HomeScreen(),
+        ),
+        GoRoute(
+          path: '/login',
+          builder: (BuildContext context, GoRouterState state) =>
+              const LoginScreen(),
+        ),
+      ];
+
+      final GoRouter router = await createRouter(routes, tester,
+          redirect: (BuildContext context, GoRouterState state) {
+        // This should not throw an exception
+        capturedRouter = GoRouter.of(context);
+        return state.matchedLocation == '/login' ? null : '/login';
+      });
+
+      expect(capturedRouter, isNotNull);
+      expect(capturedRouter, equals(router));
+    });
+
+    testWidgets('Context extension methods should work in redirects',
+        (WidgetTester tester) async {
+      String? capturedNamedLocation;
+      final List<GoRoute> routes = <GoRoute>[
+        GoRoute(
+          path: '/',
+          name: 'home',
+          builder: (BuildContext context, GoRouterState state) =>
+              const HomeScreen(),
+        ),
+        GoRoute(
+          path: '/login',
+          name: 'login',
+          builder: (BuildContext context, GoRouterState state) =>
+              const LoginScreen(),
+        ),
+      ];
+
+      await createRouter(routes, tester,
+          redirect: (BuildContext context, GoRouterState state) {
+        // This should not throw an exception
+        capturedNamedLocation = context.namedLocation('login');
+        return state.matchedLocation == '/login' ? null : '/login';
+      });
+
+      expect(capturedNamedLocation, '/login');
+    });
+
     testWidgets('redirect can redirect to same path',
         (WidgetTester tester) async {
       final List<GoRoute> routes = <GoRoute>[