flutter_bug_in_onPopPage.dart

import 'package:flutter/material.dart';

void main() {
  runApp(MainApp());
}

class MainApp extends StatelessWidget {
  final RouterDelegate<AppState> _routerDelegate = MainRouterDelegate();

  MainApp({super.key});
  @override
  Widget build(BuildContext context) =>
    MaterialApp.router(
      routerDelegate: _routerDelegate,
      backButtonDispatcher: RootBackButtonDispatcher(),
    );
}

class MainRouterDelegate extends RouterDelegate<AppState>
    with ChangeNotifier, PopNavigatorRouterDelegateMixin<AppState> {

  @override
  final GlobalKey<NavigatorState> navigatorKey;
  
  MainRouterDelegate() : navigatorKey = GlobalKey<NavigatorState>();

  @override
  Widget build(BuildContext context) => Navigator(
      key: navigatorKey,
      pages: const [
        MaterialPage(child: InnerScreen(text: "Inner screen 1",)),
        //Uncomment following line:
        // MaterialPage(child: InnerScreen(text: "Inner screen 2",))
      ],
      onPopPage: (route, result) {
        print('onPopPage: ${DateTime.now()}\n');

        if (!route.didPop(result)) {
          return false;
        }
        return false;
      },
    );

  @override
  Future<void> setNewRoutePath(final AppState configuration) async {
  }
}

class AppState extends ChangeNotifier {
}


class InnerScreen extends StatelessWidget {
  const InnerScreen({super.key, required this.text});

  final String text;

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(),
      body: Center(
        child: Column(
          children: [
            Text(text),
          ],
        ),
      ),
    );
  }
}