Can not insert a widget below MaterialApp and above go_router's Navigator

[whollacsek]

Hi @csells, according to the docs https://gorouter.dev/navigator-builder

Sometimes it is necessary to insert a widget above the Navigator, but below MaterialApp/CupertinoApp

For these purposes, you need to use the navigatorBuilder parameter in the GoRouter constructor. This is similar to the builder parameter in the MaterialApp constructor, but gives access to infrastructure provided by MaterialApp.

However I ran into an issue where I provided a wrapper widget to navigatorBuilder while defining my go_router instance, but this wrapper widget does not have access to the MaterialApp context. In this widget I'm calling showModalBottomSheet which throws:

The following assertion was thrown while handling a gesture:
Navigator operation requested with a context that does not include a Navigator.
The context used to push or pop routes from the Navigator must be that of a widget that is a
descendant of a Navigator widget.
When the exception was thrown, this was the stack:
#0      Navigator.of.<anonymous closure> (package:flutter/src/widgets/navigator.dart:2553:9)
#1      Navigator.of (package:flutter/src/widgets/navigator.dart:2560:6)
#2      showModalBottomSheet (package:flutter/src/material/bottom_sheet.dart:694:46)
...

My go_router instance is defined as:

final _router = GoRouter(
  routes: [...],
  navigatorBuilder: (context, state, child) {
    return MyWrapperWidget(child: child);
  },
);

And the MyWrapperWidget displays on all routes a button that when clicked should show a bottom sheet modal.

How can I have a wrapper around all pages that can access the Navigator from MaterialApp?

[csells]

This is the expected behavior, since you've explicitly chosen to add content about the go_router-provided Navigator instance. If you'd like to provide you own Navigator for this kind of thing, you can do so as shown in the shared scaffold sample.

[esDotDev]

Pretty sure this should work fine, can you post a basic reproduction snippet?

[whollacsek]

Thanks @esDotDev I'll prepare a repo today and hopefully you'll be able to guide me through it

[whollacsek]

@esDotDev @csells I've made the repo https://github.com/whollacsek/go_router_navigator_crash the crash happens when the Navigator is injected dynamically in navigatorBuilder. The important things are in main.dart and wrapper.dart. Let me know if you need me to clarify things

[esDotDev]

Looks like you're trying to wrap GoRouters' navigator (child), in a second Navigator, that sometimes disappears from the tree. Not sure why it is blowing up, but that seems like maybe some bug in Navigator which is probably nothing GoRouter can control.

Instead of conditionally adding the navigator, keep it in the tree, and just modify the child instead?

bool loggedIn = container.read(loginInfoProvider).loggedIn;
if(loggedIn) child = Authenticated(child: child);
return Navigator(
  onPopPage: (route, dynamic result) {
    route.didPop(result);
    return false; // don't pop the single page on the root navigator
  },
  pages: [MaterialPage<void>(child: child)],
)

[whollacsek]

I see, I'll go with your suggestion. I wanted to have a semantically correct tree, but seems like for now I'll have to go with this, thanks for taking the time @esDotDev @csells