Async.Await 未捕获任务异常 [英] Async.Await not catching Task exception

问题描述

我有一个不返回任何内容的任务.您不能对此类任务执行 Async.AwaitTask，因此您需要执行 Async.AwaitIAsyncTask.不幸的是，这似乎只是吞下了基础任务抛出的任何异常:-

I have a Task that does not return anything. You can't do an Async.AwaitTask on such a Task, so you need to do an Async.AwaitIAsyncTask instead. Unfortunately this seems to just swallow any exceptions that the underlying Task throws out: -

TaskFactory().StartNew(Action(fun _ -> failwith "oops"))
|> Async.AwaitIAsyncResult
|> Async.Ignore
|> Async.RunSynchronously

// val it : unit = ()

另一方面，AwaitTask 正确地级联异常:-

On the other hand, AwaitTask correctly cascades the exception: -

TaskFactory().StartNew(fun _ -> failwith "oops"                               
                                5)
|> Async.AwaitTask
|> Async.Ignore
|> Async.RunSynchronously

// POP!

将常规(非通用)任务视为异步但仍会传播异常的最佳方法是什么?

What's the best way of treating regular (non-generic) Tasks as Async yet still get propagation of exceptions?

推荐答案

来自 Xamarin F# Shirt App(我最初是从 Dave Thomas 那里借来的):

From the Xamarin F# Shirt App (which I originally borrowed from Dave Thomas):

[<AutoOpen>]
module Async =
     let inline awaitPlainTask (task: Task) = 
        // rethrow exception from preceding task if it faulted
        let continuation (t : Task) = if t.IsFaulted then raise t.Exception
        task.ContinueWith continuation |> Async.AwaitTask

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