Flutter Auto route error "...must be that of a widget that is a descendant of an AutoRouter widget."

I understand the problem but I don't know the solution.

In main.dart I have a Scaffold with a Drawer menu. The Drawer menu provides a link to the About page.

builder: (BuildContext context, themeProvider, child) {
          return MaterialApp(
            home: Scaffold(
              endDrawer: MenuDrawer(),
              body: MaterialApp.router(
                routerConfig: _appRouter.config(),
              ),
            ), //end Scaffold
           ); //end MaterialApp

This loads my initial route (the HOME page).

Inside the Menu Drawer the "About" button link is coded like this:

OutlinedButton(
   child: const Text("ABOUT PAGE"),
   onPressed: () {
      context.router.pushNamed('/about');
   },
),

....but when I press this button I get the error:

══╡ EXCEPTION CAUGHT BY GESTURE
The following assertion was thrown while handling a gesture: AutoRouter operation requested with a context that does not include an AutoRouter. The context used to retrieve the Router must be that of a widget that is a descendant of an AutoRouter widget.

As I understand it, this is because the menu drawer resides in the main body, not in the body of "home". But I don't want to have a menu for each specific page (or an appbar and menu for each page)...I just want one above all the pages. So how do I modify my onPressed code to work?

If I understood correctly, you may just simplify your setup a little to avoid additional nesting (MaterialApp.router inside MaterialApp). That's how you'll have a single context for all pages:

@override
  Widget build(BuildContext context) {
    return MaterialApp.router(
      routerConfig: _appRouter.config(),
      builder: (context, router) {
        return Scaffold(
          endDrawer: MenuDrawer(),
          body: router,
        );
      },
    );
  }

Another option is to use nested navigation. After discussion in comments, I actually think it's more robust way.

First, read about nested navigation [here]

Config has to be modified:

@AutoRouterConfig()
class AppRouter extends RootStackRouter {
  @override
  List<AutoRoute> get routes => [
        // nesting starts here.
        AutoRoute(
          path: '/',
          page: RootRoute.page,
          children: [
            // sample routes
            AutoRoute(path: '', page: HomeRoute.page),
            AutoRoute(path: 'about', page: AboutRoute.page),
          ],
        ),
      ];
}

So now you have 3 pages: RootPage, HomePage, AboutPage. HomePage and AboutPage are actual pages with your content (so they have different names I guess). RootPage is technical page and should include all your drawers, appears and other navigation-specific stuff. Example:

@RoutePage()
class RootPage extends StatelessWidget {
  const RootPage({Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return AutoTabsScaffold(
      appBarBuilder: (_, tabsRouter) => AppBar(
        title: const Text('My App'),
      ),
      endDrawer: const MenuDrawer(),
    );
  }
}

You main build method will look like this now:

  @override
  Widget build(BuildContext context) {
    return MaterialApp.router(
      routerConfig: _appRouter.config(),
    );
  }

Meaning you provides only router config to build method and AutoRouter takes care of other things.

I also created a GitHub example to better explain the concept, repository is here. Feel free to look and use in your code, it needed.