_args.Sender error

General
1

I’m getting this error:

ERROR: _args.Sender was null
    System.Exception occured.
       at Fuse.Reactive.CrossThreadExceptionHandler.CheckAndThrow() in C:\ProgramData\Uno\Packages\Fuse.Reactive\0.18.8\$.uno:line 1540
       at Fuse.Reactive.JavaScript.HandleWorkerException() in C:\ProgramData\Uno\Packages\Fuse.Reactive\0.18.8\$.uno:line 1580
       at Fuse.UpdateListener.Invoke() in C:\ProgramData\Uno\Packages\FuseCore\0.18.8\$.uno:line 6596
       at Fuse.UpdateManager.Update(Stage stage) in C:\ProgramData\Uno\Packages\FuseCore\0.18.8\$.uno:line 6817
LOG: One or more errors occurred.

It happens generally when I’m clearing an observable list and replacing it’s contents, but, sometimes this happens literally after a few seconds when I don’t do anything. I think its specific to my project, but I can just press Restart and then try again and it’ll work but it can take a few restarts.

This also never happens when I build to device (not preview).

Cheers

2

Without knowing the JS source for me it seems like a possible async workers issue ex. clearing an observable in a timer while still processing it in another async loop. The way I’m using observable list is to put a flag ahead of processing and unflag when done (like a semaphore). I haven’t seen that exception yet though. Hope it helps.

3

Do you have a project that we can use to reproduce this? Are you on Mac or Windows?

4

I can’t isolate it. There’s a lot of observables being manipulated at the same time, and there is a timer running, but it isn’t/shouldn’t be touching any observable list.

I don’t want to release the source publicly.

I’m on Windows.

UPDATE

When I check the observable list just before the app crashes, every single subscriber is null, I’m not sure what that means or how I can prevent it, but I think this is where it’s going wrong

5

This happened when the observable values was replaced using clear and then add, instead of using replaceAll. So the nodes was unrooted and the event could not execute. I have added a better errormessage to handle this case differently in the future.