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C#代码在进入DEBUG构建中的前几行之前执行

debugging multithreading c#

Adrian · 技术社区 · 3 年前

我不知所措。我有一个任务工厂正在启动一个功能:

        Task.Factory.StartNew(() => ServerGetSecureLog(ServerAndProjectorArchive);

        private static void ServerGetSecureLog(string archivePath)
        {
            var localClientManager = InitializeConnection();
            var destinationPath = $"{ServerSecureLogFile}";

            var result = ServerGetBasicSecureLogAsync(localClientManager);
            var sw = StartStopwatch();
            //Wait upto 120s
            if (!result.Wait(TimeSpan.FromSeconds(120))) // <<< Exception thrown here.
            {
                StopStopwatch(sw);
                log.Warn($"{MethodBase.GetCurrentMethod().Name} took too long to execute (timeout exceeded).");
            }
            else
            {
                StopStopwatch(sw);

问题是,我得到了 System.AggregateException 如上所示被投掷。我一定快疯了。,因为要调试它,我在之前的每一行代码上都设置了断点,在同一行抛出异常,甚至是启动线程的行和调用的lambda,但它们都没有被命中。向上走一个堆栈帧,就可以调用我放置断点的lambda。

可变状态: localClientManager 看起来还未初始化,所以IP似乎不知怎么被劫持了。

我不希望优化器对DEBUG构建做任何事情,并且代码中没有不安全的区域。是什么导致了这种集市行为?

编辑

远程调试可能是个问题吗?不幸的是,我无法在该系统上安装调试器,也无法从本地计算机上真正运行应用程序。

0 回复 | 直到 3 年前

Rafael Diego Nicoletti 3 年前

每当任务在失败状态下运行到完成时,也就是说,当运行该任务的方法以某种方式失败时,它就会抛出AggregateException。

这是因为任务可以继续:

var t = SomeAsyncMethod().ContinueWith(a=> { });

如果SomeAsyncMethod抛出异常,ContinueWith也抛出异常,则聚合异常将具有该调用的所有异常。

然而,当您使用async/await调用并尝试/catch时,c#async state会展开聚合异常,并在代码中抛出原始异常。

代码中的问题与GetServerLog方法是同步的并且正在调用Task方法有关。您可以:

var localClientManager = InitializeConnection();
var destinationPath = $"{ServerSecureLogFile}";
//Wait upto 120s
var cts = new CancellationTokenSource(TimeSpan.FromSeconds(120));
// assumes that this method will look at the token to stop processing and bubbling up a OperationCancelledException/TimeoutException if token expires.
// localClientManager can be null if InitializeConnection returns null or depends on other lazy/async initialization steps.

var result = ServerGetBasicSecureLogAsync(localClientManager, cts.Token);

var sw = Stopwatch.StartNew();
try 
{
    // This can cause deadlocks it Thread pool threads are waiting for a free thread and other locations are doing Waits: https://stackoverflow.com/questions/13140523/await-vs-task-wait-deadlock

    //result.WaitOne(TimeSpan.FromSeconds(120));
    result.GetAwaiter().GetResult();

}
catch(MySimpleException)
{
}
catch(OperationCancelledException)
{
}
finally
{
   sw.Stop();
    // could enclose cts in using statement
   cts.Dispose();
}

因为GetAwaiter().GetResult()是异步状态调用的相同方法,所以它还展开聚合异常,通过使用try/catch,您也可以查看取消的操作。

此外,您不需要创建Task来运行异步方法:

async Task SomeAsyncMethod()
{
    var localClientManager = InitializeConnection();
    var destinationPath = $"{ServerSecureLogFile}";
    //Wait upto 120s
    var cts = new CancellationTokenSource(TimeSpan.FromSeconds(120));
    // assumes that this method will look at the token to stop processing and bubbling up a OperationCancelledException/TimeoutException if token expires.
    // localClientManager can be null if InitializeConnection returns null or depends on other lazy/async initialization steps.
    var sw = Stopwatch.StartNew();
    try 
    {
        await ServerGetBasicSecureLogAsync(localClientManager, cts.Token);
    }
    catch(MySimpleException)
    {
    }
    catch(OperationCancelledException)
    {
    }
    finally
    {
        sw.Stop();
        // could enclose cts in using statement
       cts.Dispose();
    }
}

// this call will never throw as long as method is catching and handling exceptions
SomeAsyncMethod().GetAwaiter().GetResult();