Is calling ref.watch(myAuthProvider.future) inside of a GoRouter.redirect a bad practice?

[sashkent3]

I've been in search of a simple solution for integrating riverpod with the go_router package in terms of reacting to authentication state changes. I've since seen a lot of conflicting complicated solutions none of which were satisfactory.
It seems that from the go_router side the recommended solution is to utilize BuildContext.dependOnInheritedWidgetOfExactType inside of the GoRouter.redirect function. My question then is then twofold:

1. Does the ref.watch() call BuildContext.dependOnInheritedWidgetOfExactType internally?
2. What happens if I call ref.watch() inside of a GoRouter.redirect?

[rrousselGit]

Does the ref.watch() call BuildContext.dependOnInheritedWidgetOfExactType internally?

Yes, but actually no 🤷
It does call that method. But that's not going to do what you want.

The part that triggers a rebuild of a Consumer isn't done through BuildContext.dependOnInheritedWidgetOfExactType, but instead calling Element.markNeedsBuild.
As such, go_router natively has no idea that a provider changed for now.

What happens if I call ref.watch() inside of a GoRouter.redirect?

GoRouter doesn't give you a ref. A Consumer did. What will happen is, the Consumer that gave you the Ref will rebuild.

[sashkent3]

If I understood you correctly, the ref.watch() approach will always cause the GoRouter to be rebuilt on provider state changes which is undesirable. It then seems to me that it's best/simplest to use a provider's Provider for the authentication state. I can then use riverpod's ChangeNotifierProvider adapter for all of my riverpod needs. Any downsides?

[rrousselGit]

ref.watch doesn't cause GoRouter to rebuild. It causes your Consumer to rebuild. GoRouter naturally has no clue that something changed

[sashkent3]

I mean the app would look something like:

class MyApp extends ConsumerWidget {
  const MyApp({super.key});

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    return MaterialApp.router(
      routerConfig: GoRouter(
        redirect: (context, state) async {
          final user = ref.watch(myAuthProvider.provider);
        },
      )
    );
  }
}

Here every time the auth state changes we rebuild the whole app including the GoRouter, correct?