[go_router_builder] add support to go_router_builder for initializing…

… a StatefulShellBranch with observers (#5865)

This pr added the ability to provide a list of NavigatorObservers to a StatefulShellBranch. 
The equivalent was never added to go_router_builder, so this pr provides that functionality.

With this change, you can provide NavigatorObservers directly to the StatefulShellBranch and fix flutter/flutter#143869.

packages/go_router_builder/CHANGELOG.md

@@ -1,3 +1,7 @@
+## 2.6.0
+
+* Adds support for passing observers to the StatefulShellBranch for the nested Navigator.
+
 ## 2.5.1
 
 - Updates examples to use uri.path instead of uri.toString() for accessing the current location.

packages/go_router_builder/lib/src/route_config.dart

@@ -146,6 +146,7 @@ class StatefulShellBranchConfig extends RouteBaseConfig {
     required this.navigatorKey,
     required super.routeDataClass,
     required super.parent,
+    required this.observers,
     this.restorationScopeId,
     this.initialLocation,
   }) : super._();
@@ -159,6 +160,9 @@ class StatefulShellBranchConfig extends RouteBaseConfig {
   /// The initial route.
   final String? initialLocation;
 
+  /// The navigator observers.
+  final String? observers;
+
   @override
   Iterable<String> classDeclarations() => <String>[];
 
@@ -168,7 +172,8 @@ class StatefulShellBranchConfig extends RouteBaseConfig {
   String get routeConstructorParameters =>
       '${navigatorKey == null ? '' : 'navigatorKey: $navigatorKey,'}'
       '${restorationScopeId == null ? '' : 'restorationScopeId: $restorationScopeId,'}'
-      '${initialLocation == null ? '' : 'initialLocation: $initialLocation,'}';
+      '${initialLocation == null ? '' : 'initialLocation: $initialLocation,'}'
+      '${observers == null ? '' : 'observers: $observers,'}';
 
   @override
   String get routeDataClassName => 'StatefulShellBranchData';
@@ -521,6 +526,10 @@ abstract class RouteBaseConfig {
             classElement,
             parameterName: r'$initialLocation',
           ),
+          observers: _generateParameterGetterCode(
+            classElement,
+            parameterName: r'$observers',
+          ),
         );
       case 'TypedGoRoute':
         final ConstantReader pathValue = reader.read('path');

packages/go_router_builder/pubspec.yaml

@@ -2,12 +2,13 @@ name: go_router_builder
 description: >-
   A builder that supports generated strongly-typed route helpers for
   package:go_router
-version: 2.5.1
+version: 2.6.0
 repository: https://github.com/flutter/packages/tree/main/packages/go_router_builder
 issue_tracker: https://github.com/flutter/flutter/issues?q=is%3Aissue+is%3Aopen+label%3A%22p%3A+go_router_builder%22
 
 environment:
   sdk: ^3.1.0
+  flutter: ">=3.13.0"
 
 dependencies:
   analyzer: ">=5.2.0 <7.0.0"
@@ -23,6 +24,8 @@ dependencies:
 dev_dependencies:
   build_test: ^2.1.7
   dart_style: 2.3.2
+  flutter:
+    sdk: flutter
   go_router: ^10.0.0
   test: ^1.20.0
 

packages/go_router_builder/test_inputs/statefull_shell_branch_with_observers_data.dart

@@ -0,0 +1,14 @@
+// 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/widgets.dart';
+import 'package:go_router/go_router.dart';
+
+@TypedStatefulShellBranch<StatefulShellBranchWithObserversData>()
+class StatefulShellBranchWithObserversData extends StatefulShellBranchData {
+  const StatefulShellBranchWithObserversData();
+
+  static const String $initialLocation = '/main/second-tab';
+  static const List<NavigatorObserver> $observers = <NavigatorObserver>[];
+}

packages/go_router_builder/test_inputs/statefull_shell_branch_with_observers_data.dart.expect

@@ -0,0 +1,5 @@
+RouteBase get $statefulShellBranchWithObserversData =>
+    StatefulShellBranchData.$branch(
+      initialLocation: StatefulShellBranchWithObserversData.$initialLocation,
+      observers: StatefulShellBranchWithObserversData.$observers,
+    );