StatefulShellRouteData generated as const on extension

[on3ss]

Steps to reproduce

1. create a StatefulShellRouteData with multiple branches but single route for each branch
2. Add a custom scaffold for nesting routes with a bottom navigation bar

Expected results

on the generated file, the extension on the class that extends StatefulShellRouteData must not be returned as const.

Actual results

on the generated file, the extension on the class that extends StatefulShellRouteData returned as const.

Code sample

Code sample

import 'package:academix/features/chat/chat.dart';
import 'package:academix/features/homework/homework.dart';
import 'package:academix/features/my_class/my_class.dart';
import 'package:academix/widgets/scaffold_with_nested_navigation.dart';
import 'package:flutter/material.dart';
import 'package:go_router/go_router.dart';
import 'package:academix/features/home/home.dart';

import '../features/assignments/assignments.dart';

part 'router.g.dart';

@TypedStatefulShellRoute<AppShellRouteData>(
  branches: [
    TypedStatefulShellBranch(
      routes: [TypedGoRoute<HomePageRoute>(path: '/')],
    ),
    TypedStatefulShellBranch(
      routes: [TypedGoRoute<MyClassPageRoute>(path: '/my-class')],
    ),
    TypedStatefulShellBranch(
      routes: [TypedGoRoute<HomeworkPageRoute>(path: '/homework')],
    ),
    TypedStatefulShellBranch(
      routes: [TypedGoRoute<AssignmentsPageRoute>(path: '/assignments')],
    ),
    TypedStatefulShellBranch(
      routes: [TypedGoRoute<ChatPageRoute>(path: '/chat')],
    ),
  ],
)
class AppShellRouteData extends StatefulShellRouteData {
  @override
  Widget builder(
    BuildContext context,
    GoRouterState state,
    StatefulNavigationShell navigationShell,
  ) =>
      ScaffoldWithNestedNavigation(navigationShell: navigationShell);
}

@immutable
class HomePageRoute extends GoRouteData {
  @override
  Widget build(BuildContext context, GoRouterState state) {
    return const MyHomePage();
  }
}

@immutable
class MyClassPageRoute extends GoRouteData {
  @override
  Widget build(BuildContext context, GoRouterState state) {
    return const MyClassPage();
  }
}

@immutable
class AssignmentsPageRoute extends GoRouteData {
  @override
  Widget build(BuildContext context, GoRouterState state) {
    return const AssignmentsPage();
  }
}

@immutable
class HomeworkPageRoute extends GoRouteData {
  @override
  Widget build(BuildContext context, GoRouterState state) {
    return const HomeworkPage();
  }
}

@immutable
class ChatPageRoute extends GoRouteData {
  @override
  Widget build(BuildContext context, GoRouterState state) {
    return const ChatPage();
  }
}

Screenshots or Video

Screenshots / Video demonstration

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Logs

Logs

lib/router/router.g.dart:61:13: Error: Cannot invoke a non-'const' constructor where a const expression is expected.
Try using a constructor or factory that is 'const'.
      const AppShellRouteData();

Flutter Doctor output

Doctor output

Doctor summary (to see all details, run flutter doctor -v):
[✓] Flutter (Channel stable, 3.27.1, on Microsoft Windows [Version 10.0.26100.2605], locale en-IN)
[✓] Windows Version (Installed version of Windows is version 10 or higher)
[!] Android toolchain - develop for Android devices (Android SDK version 35.0.0)
    ! Some Android licenses not accepted. To resolve this, run: flutter doctor --android-licenses
[✗] Chrome - develop for the web (Cannot find Chrome executable at .\Google\Chrome\Application\chrome.exe)
    ! Cannot find Chrome. Try setting CHROME_EXECUTABLE to a Chrome executable.
[✗] Visual Studio - develop Windows apps
    ✗ Visual Studio not installed; this is necessary to develop Windows apps.
      Download at https://visualstudio.microsoft.com/downloads/.
      Please install the "Desktop development with C++" workload, including all of its default components
[✓] Android Studio (version 2024.2)
[✓] Connected device (3 available)
[✓] Network resources

! Doctor found issues in 3 categories.

[on3ss]

The generated code:

// GENERATED CODE - DO NOT MODIFY BY HAND

part of 'router.dart';

// **************************************************************************
// GoRouterGenerator
// **************************************************************************

List<RouteBase> get $appRoutes => [
      $appShellRouteData,
    ];

RouteBase get $appShellRouteData => StatefulShellRouteData.$route(
      factory: $AppShellRouteDataExtension._fromState,
      branches: [
        StatefulShellBranchData.$branch(
          routes: [
            GoRouteData.$route(
              path: '/',
              factory: $HomePageRouteExtension._fromState,
            ),
          ],
        ),
        StatefulShellBranchData.$branch(
          routes: [
            GoRouteData.$route(
              path: '/my-class',
              factory: $MyClassPageRouteExtension._fromState,
            ),
          ],
        ),
        StatefulShellBranchData.$branch(
          routes: [
            GoRouteData.$route(
              path: '/homework',
              factory: $HomeworkPageRouteExtension._fromState,
            ),
          ],
        ),
        StatefulShellBranchData.$branch(
          routes: [
            GoRouteData.$route(
              path: '/assignments',
              factory: $AssignmentsPageRouteExtension._fromState,
            ),
          ],
        ),
        StatefulShellBranchData.$branch(
          routes: [
            GoRouteData.$route(
              path: '/chat',
              factory: $ChatPageRouteExtension._fromState,
            ),
          ],
        ),
      ],
    );

extension $AppShellRouteDataExtension on AppShellRouteData {
  static AppShellRouteData _fromState(GoRouterState state) =>
      const AppShellRouteData();
}

extension $HomePageRouteExtension on HomePageRoute {
  static HomePageRoute _fromState(GoRouterState state) => HomePageRoute();

  String get location => GoRouteData.$location(
        '/',
      );

  void go(BuildContext context) => context.go(location);

  Future<T?> push<T>(BuildContext context) => context.push<T>(location);

  void pushReplacement(BuildContext context) =>
      context.pushReplacement(location);

  void replace(BuildContext context) => context.replace(location);
}

extension $MyClassPageRouteExtension on MyClassPageRoute {
  static MyClassPageRoute _fromState(GoRouterState state) => MyClassPageRoute();

  String get location => GoRouteData.$location(
        '/my-class',
      );

  void go(BuildContext context) => context.go(location);

  Future<T?> push<T>(BuildContext context) => context.push<T>(location);

  void pushReplacement(BuildContext context) =>
      context.pushReplacement(location);

  void replace(BuildContext context) => context.replace(location);
}

extension $HomeworkPageRouteExtension on HomeworkPageRoute {
  static HomeworkPageRoute _fromState(GoRouterState state) =>
      HomeworkPageRoute();

  String get location => GoRouteData.$location(
        '/homework',
      );

  void go(BuildContext context) => context.go(location);

  Future<T?> push<T>(BuildContext context) => context.push<T>(location);

  void pushReplacement(BuildContext context) =>
      context.pushReplacement(location);

  void replace(BuildContext context) => context.replace(location);
}

extension $AssignmentsPageRouteExtension on AssignmentsPageRoute {
  static AssignmentsPageRoute _fromState(GoRouterState state) =>
      AssignmentsPageRoute();

  String get location => GoRouteData.$location(
        '/assignments',
      );

  void go(BuildContext context) => context.go(location);

  Future<T?> push<T>(BuildContext context) => context.push<T>(location);

  void pushReplacement(BuildContext context) =>
      context.pushReplacement(location);

  void replace(BuildContext context) => context.replace(location);
}

extension $ChatPageRouteExtension on ChatPageRoute {
  static ChatPageRoute _fromState(GoRouterState state) => ChatPageRoute();

  String get location => GoRouteData.$location(
        '/chat',
      );

  void go(BuildContext context) => context.go(location);

  Future<T?> push<T>(BuildContext context) => context.push<T>(location);

  void pushReplacement(BuildContext context) =>
      context.pushReplacement(location);

  void replace(BuildContext context) => context.replace(location);
}

[darshankawar]

Code sample

@on3ss I code sample you shared here can you provide only minimal or complete runnable one ? I see that you have lot of imports there, but try to trim down to absolutely minimum code that still triggers the reported error.

[on3ss]

Sure. Here is the minimal code required to run:

// router.dart
import 'package:flutter/material.dart';
import 'package:go_router/go_router.dart';
import 'package:academix/ui/home/home.dart';

part 'router.g.dart';

@TypedStatefulShellRoute<AppShellRouteData>(
  branches: [
    TypedStatefulShellBranch(
      routes: [TypedGoRoute<HomeScreenRoute>(path: '/')],
    ),
  ],
)
class AppShellRouteData extends StatefulShellRouteData {
  @override
  Widget builder(
    BuildContext context,
    GoRouterState state,
    StatefulNavigationShell navigationShell,
  ) =>
      HomeScreen();
}

@immutable
class HomeScreenRoute extends GoRouteData {
  @override
  Widget build(BuildContext context, GoRouterState state) {
    return const HomeScreen();
  }
}

//home.dart
import 'package:flutter/material.dart';

class HomeScreen extends StatelessWidget {
  const HomeScreen({super.key});

  @override
  Widget build(BuildContext context) {
    return Scaffold(body: Placeholder());
  }
}

[darshankawar]

Thanks for the update. I was able to replicate the reported behavior using details provided above.

stable : 3.27.1
master : 3.28.0-2.0.pre.38691

[on3ss]

Can we expect a fix for this with the next update? For those who often use build_runner with their project this can be annoying.