Bug 17712 - TaskScheduler.UnobservedTaskException raised for trapped exceptions
Summary: TaskScheduler.UnobservedTaskException raised for trapped exceptions
Status: RESOLVED FIXED
Alias: None
Product: Class Libraries
Classification: Mono
Component: mscorlib ()
Version: 3.2.x
Hardware: PC Mac OS
: --- normal
Target Milestone: Untriaged
Assignee: Bugzilla
URL:
Depends on:
Blocks:
 
Reported: 2014-02-11 17:36 UTC by Jonathan Pryor
Modified: 2014-02-11 17:37 UTC (History)
1 user (show)

Tags:
Is this bug a regression?: ---
Last known good build:

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Status:
RESOLVED FIXED

Description Jonathan Pryor 2014-02-11 17:36:44 UTC
(Looks like Bug #17699 redux!)

Please see test case at: https://bitbucket.org/tpurtell/xa4.12alpha-gc-async-exceptions

The test case loads a URL which doesn't exist within an async method, and handles the method:

    static async Task FailedWebRequest()
    {
      var client = new HttpClient();
      try
      {
        var result = await client.GetStringAsync("http://127.0.0.1/doesNOTexist");
        Console.WriteLine("Got valid result?: {0}", result);
      }
      catch (Exception e)
      {
          Console.WriteLine("Caught Exception: {0}", e.Message);
      }
    }

Note that any exceptions are handled.

Meanwhile, we subscribe to the TaskScheduler.UnobservedTaskException event. The TaskScheduler.UnobservedTaskException event is still raised, despite the Task being handled.
Comment 2 Jonathan Pryor 2014-02-11 17:37:30 UTC
Should be fixed in: https://github.com/mono/mono/commit/c1539ef0