How Can I Handle Exceptions in a 'Fire and Forget' Async Method?

Fire and Forget with Guaranteed Exception Propagation

In a "Fire and Forget" approach, a method is invoked without waiting for its completion or handling its result. However, when a method returns a task, it is not truly "Fire and Forget." Exceptions thrown within the task are not propagated to the calling context.

To ensure that exceptions in "Fire and Forget" methods are handled or escalated, it is recommended to modify the extension method as follows:

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

By awaiting the task, any exceptions thrown within the task will be propagated to the calling context and handled or escalated accordingly.

Handling Expected Exceptions in "Fire and Forget" Methods

The original question raises a concern about methods that may throw expected and ignorable exceptions in a "Fire and Forget" context. To address this, the extension method can be modified to accept a list of acceptable exception types:

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;
    }
}

This allows the caller to specify which exception types should be ignored and which should be escalated, providing greater control over the exception handling behavior in "Fire and Forget" methods.

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