[go_router] Fix replace routes hanging the originating completer

Author: nouvist

packages/go_router/CHANGELOG.md

@@ -1,5 +1,7 @@
-## NEXT
+## 15.1.3
 
+* Fixes an issue where `replace` and `pushReplacement` caused the originating route's completer to hang.
+  [flutter#141251](https://github.com/flutter/flutter/issues/141251)
 * Updates minimum supported SDK version to Flutter 3.27/Dart 3.6.
 
 ## 15.1.2

packages/go_router/lib/src/parser.dart

@@ -168,6 +168,18 @@ class GoRouteInformationParser extends RouteInformationParser<RouteMatchList> {
     return redirectedFuture;
   }
 
+  /// Ensures the replacement routes can resolve the originating route completer.
+  Completer<T?>? _createInheritedCompleter<T>(
+    Completer<T?> current,
+    RouteMatch lastRouteMatch,
+  ) {
+    if (lastRouteMatch is ImperativeRouteMatch) {
+      return _InheritedCompleter<T?>(current, lastRouteMatch.completer);
+    } else {
+      return current;
+    }
+  }
+
   RouteMatchList _updateRouteMatchList(
     RouteMatchList newMatchList, {
     required RouteMatchList? baseRouteMatchList,
@@ -185,6 +197,7 @@ class GoRouteInformationParser extends RouteInformationParser<RouteMatchList> {
         );
       case NavigatingType.pushReplacement:
         final RouteMatch routeMatch = baseRouteMatchList!.last;
+        completer = _createInheritedCompleter(completer!, routeMatch);
         baseRouteMatchList = baseRouteMatchList.remove(routeMatch);
         if (baseRouteMatchList.isEmpty) {
           return newMatchList;
@@ -198,6 +211,7 @@ class GoRouteInformationParser extends RouteInformationParser<RouteMatchList> {
         );
       case NavigatingType.replace:
         final RouteMatch routeMatch = baseRouteMatchList!.last;
+        completer = _createInheritedCompleter(completer!, routeMatch);
         baseRouteMatchList = baseRouteMatchList.remove(routeMatch);
         if (baseRouteMatchList.isEmpty) {
           return newMatchList;
@@ -224,3 +238,34 @@ class GoRouteInformationParser extends RouteInformationParser<RouteMatchList> {
         List<int>.generate(32, (_) => _random.nextInt(33) + 89)));
   }
 }
+
+/// Ensures the replacement routes can resolve the originating route completer.
+/// Mainly used by [GoRouteInformationParser._createInheritedCompleter].
+class _InheritedCompleter<T extends Object?> implements Completer<T> {
+  _InheritedCompleter(this._current, this._last);
+
+  final Completer<T> _current;
+  final Completer<Object?> _last;
+
+  @override
+  void complete([FutureOr<T>? value]) {
+    _current.complete(value);
+    if (!_last.isCompleted) {
+      _last.complete(value);
+    }
+  }
+
+  @override
+  void completeError(Object error, [StackTrace? stackTrace]) {
+    _current.completeError(error, stackTrace);
+    if (!_last.isCompleted) {
+      _last.completeError(error, stackTrace);
+    }
+  }
+
+  @override
+  Future<T> get future => _current.future;
+
+  @override
+  bool get isCompleted => _current.isCompleted;
+}

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: 15.1.2
+version: 15.1.3
 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/imperative_api_test.dart

@@ -2,6 +2,8 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+import 'dart:math';
+
 import 'package:flutter/material.dart';
 import 'package:flutter_test/flutter_test.dart';
 import 'package:go_router/go_router.dart';
@@ -294,4 +296,49 @@ void main() {
     expect(find.text('shell'), findsNothing);
     expect(find.byKey(e), findsOneWidget);
   });
+
+  testWidgets('completer able to be passed on replace',
+      (WidgetTester tester) async {
+    final List<RouteBase> routes = <RouteBase>[
+      GoRoute(
+        path: '/initial',
+        builder: (BuildContext context, GoRouterState state) =>
+            const DummyScreen(),
+      ),
+      GoRoute(
+        path: '/intermediate',
+        builder: (BuildContext context, GoRouterState state) =>
+            const DummyScreen(),
+      ),
+      GoRoute(
+        path: '/final',
+        builder: (BuildContext context, GoRouterState state) =>
+            const DummyScreen(),
+      ),
+    ];
+
+    final GoRouter router = await createRouter(
+      routes,
+      tester,
+      initialLocation: '/initial',
+    );
+
+    final int random = Random().nextInt(1000);
+
+    final Future<Object?> push = router.push('/intermediate');
+    await tester.pumpAndSettle();
+    expect(router.state.path, '/intermediate');
+
+    final Future<int?> replace = router.replace<int>('/final');
+    await tester.pumpAndSettle();
+    expect(router.state.path, '/final');
+
+    router.pop(random);
+    await tester.pumpAndSettle();
+    expect(router.state.path, '/initial');
+    await tester.pumpAndSettle();
+
+    await expectLater(push, completion(random));
+    await expectLater(replace, completion(random));
+  });
 }