[MonoTouch] Did Threading change a lot in 5.2.latest?

[Rolf Bjarne Kvinge]

Hi,

These issues might be related. Have in mind that TestFlight will handle
NullReferenceExceptions as crashes (and won't let you catch them).

Rolf

On Thu, Mar 15, 2012 at 11:39 AM, Nic Wise <nicw at fastchicken.co.nz> wrote:

> Hi there
>
> I'm having a few issues in the newest versions of MT, mostly around
> Threading (ok, ALL around threading).
>
> this one is a fairly major, but easy to work around, one for me:
>
> https://bugzilla.xamarin.com/show_bug.cgi?id=3676
>
> I'm getting it when I use NewtonSoft Json.net from a thread. I worked
> around it by using it from the UI thread, and caching the resulting
> object (not a big deal at all in this case). The DLL I'm using hasn't
> changed for a long time.....
>
>
>
> However, I'm also having an issue with TestFlight's logging. If I log
> in a thread, sometimes, I get a segfault. Not every time, but always
> in the same place, and ALWAYS in a thread. The thread code is like
> this:
>
> Task.Factory.StartNew(() => {
>                                CalculateSummary ();
>                        }).ContinueWith(t => {
>                                if (oncomplete != null) oncomplete();
>                        }, new UIKitScheduler());
>
> (UIKitScheduler is this: https://gist.github.com/1431457 )
> CalculateSummary loads a bunch of stuff from SQLite, then the last line is:
>
> Util.Log ("recalculating took {0}ms".Fmt (sw.ElapsedMilliseconds));
>
> It is possible that the oncomplete is throwing an error, which I need
> to check out - I've had issues with threading disappearing if the
> continue throws an uncaught exception.
>
> Anywho, Util.Log does a Debug.WriteLine (or Console.WriteLine, same
> result), and a TestFlight.Log. The first works always. The latter
> crashes _sometimes_, usually if he app is busy - ie, I'm moving
> between screens (which triggers calculations) etc. But sometimes just
> if it's sitting idle. I've tried putting the logging into a
> InvokeOnMainThread, but with the same result.
>
> I wasn't using TF before, but I've not had the Json problem in
> previous versions (I have a lot of production code out there which is
> working doing this). That said, I wasn't using Tasks before (I was
> using the threadpool), which may also be it!
>
> Any ideas? did this change after 5.2.4 (I'm on 5.2.8 I think at the moment)
>
> I have a semi-stacktrace thing, but it has almost no actual info in
> it. I'm going to try a debug build tonight, and see if I can get more
> info out. console just shows that the app segfaulted (error 11 I
> think??)
>
>  Outside of that, everything is exceptionally delicious with iOS5, the
> appearance API's, and the Task API's :)
>
> N
>
> --
> Nic Wise
> t.  +44 7788 592 806 | @fastchicken | http://www.linkedin.com/in/nicwise
> b. http://www.fastchicken.co.nz/
>
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