How to catch error used after being disposed?

[stephane-archer]

How can I catch these errors in my code to display them on the screen as error messages for my user?

FlutterError (A LutPreviewImagesChangeNotifier was used after being disposed.
Once you have called dispose() on a LutPreviewImagesChangeNotifier, it can no longer be used.)

[rrousselGit]

Hard to say without some context. You didn't share much about what's happening here :)

[stephane-archer]

@rrousselGit Sorry I didn't realize I didn't give you enough context.

I try to catch Notifier was used after being disposed.

here is some context on why it happened here:

onClick: () {
var a = ref.read(aProvider.notifier);
var b = ref.read(bProvider.notifier);
a.state = null;
b.state = null; <- but bProvider has recently been change to watch for `aProvider` so this code was working correctly but now b.state uses a notifier after disposed.
}

from the screenshot I shared, I don't see b.state = null; in the call stack, so it seems like the exception was thrown later for some unknown reason (maybe because of async code?). I expected that Riverpod throw that exception but is it?

[zhxst]

Do you use ref.watch(aProvider) and ref.watch(bProvider) in the widget build method ?
This usually happens with AutoDisposeNotifier, when you forget to watch the provider, they will be disposed immediately after you call ref.read().

[stephane-archer]

This is not an AutoDisposeNotifier but both are ChangeNotifier

[rrousselGit]

Sounds like you're talking about this: #3354

[stephane-archer]

@rrousselGit it looks similar. I tried to understand the status of it. From my understanding, this will be fixed in the next major release. Is it already fixed in the dev branch?

[rrousselGit]

No. Honnestly I'm not sure how to go about it yet.