Should 'Fire and Forget' Tasks Handle Exceptions Asynchronously?

Capturing Exceptions with "Fire and Forget" Tasks

In the context of "Fire and Forget" methods that return tasks, a common approach is to use an extension method to discard them quietly. However, this approach may conceal unexpected exceptions within the task's execution.

Consider the following question: is it more prudent to define the extension method as an asynchronous one, such as:

public static async void Forget(this Task task)
{
    await task;
}

By doing so, programming errors would trigger exceptions, alerting the user to potential issues. However, this approach departs from the true "fire and forget" paradigm, where completion and success are disregarded.

Understanding the semantics of "fire and forget" is crucial here. A genuine "fire and forget" approach implies that the outcome of the task is inconsequential. Nevertheless, there may be scenarios where you want to handle specific expected exceptions while disregarding others.

Handling Expected Exceptions

To address this, the extension method can be modified as follows:

public static async void Forget(this Task task, params Type[] acceptableExceptions)
{
  try
  {
    await task.ConfigureAwait(false);
  }
  catch (Exception ex)
  {
    // TODO: consider whether derived types are also acceptable.
    if (!acceptableExceptions.Contains(ex.GetType()))
      throw;
  }
}

With this revised method, you can specify a list of acceptable exception types that should be silently handled. Any other exceptions will trigger an exception, alerting you to potential problems.

It's worth noting that using the await keyword is recommended instead of ContinueWith. This choice avoids potential scheduling issues and makes error handling more straightforward.

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