Exception handling outside of Task

Question

Just noticed strange thing: to catch exception in caller from new Task, lambda MUST be marked as async!? Is it really necessary even if delegate has no await operators at al

Answer 1

Methods that return Task - such as Task.Run or async methods - will place any exceptions on that returned Task. It's up to you to observe that exception somehow. Normally this is done with await, like this:

await Task.Run(() => { throw ... });

In your case, the problem is in this line:

result = OnSomeEvent((s, ea) => RunSomeTask());

In this code, RunSomeTask is returning a Task, and that Task is never awaited. In order to observe the exception, you should await that task.