BeforeSend not respected when exception is unhandled in a task

[georgiosd]

Package

Sentry

.NET Flavor

.NET

.NET Version

6.0.0

OS

Windows

SDK Version

3.34.0

Self-Hosted Sentry Version

No response

Steps to Reproduce

1. Override OnBeforeSend to return null when event has exception of type SomeException.
2. Throw SomeException from a Task.Run func.

Expected Result

Sentry filters out the exception.

Actual Result

Sentry still sends the exception "home".

[georgiosd]

I'm not 100% sure the repro is accurate - AFAIK it's the same conceptually with the real repro (below) but I couldn't get it to reproduce the same behavior.

"Real" repro:

1. Register a background service.
2. In ExecuteAsync add a small delay and then throw SomeException

I think this is accurate - but the issue I am seeing in production is related to UnobservedTaskException which is flooding our sentry even though we're dropping the event in OnBeforeSend. Ultimately related to this hardkoded/puppeteer-sharp#891

[bricefriha]

@georgiosd Thanks for reporting this, we're taking a look

[bricefriha]

Unfortunately, I'm unable to reproduce this yet.

@georgiosd, is it a UWP app, MAUI, or something else?
also, are you capturing the exception manually (with a SentrySdk.CaptureException(ex)), or is the exception unhandled?

[georgiosd]

This is on an ASP.NET Core 6.0 app, hence the background service - should have said `BackgroundService`. But take a look at the issue I linked above from PuppeteerSharp - I believe it’s thrown from a finalizer thread somewhere?

[jamescrosswell]

@georgiosd that Pupeteer repsitory is pretty big and there's a lot going on there. It makes it quite hard to reproduce this issue.

Are you able to provide a minimal reproduction of the issue that we could look at?

[georgiosd]

Yeah, I understand. I'll spend some time and see if I can reproduce this.