Bug 1407 - Debugging stops randomly
Summary: Debugging stops randomly
Alias: None
Product: Xamarin Studio
Classification: Desktop
Component: Debugger ()
Version: 4.1.8
Hardware: Macintosh Mac OS
: Normal normal
Target Milestone: ---
Assignee: Jeffrey Stedfast
Depends on:
Reported: 2011-10-10 18:09 UTC by Dermot
Modified: 2014-10-07 15:40 UTC (History)
3 users (show)

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

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Description Dermot 2011-10-10 18:09:06 UTC
Often, while debugging when im stepping through code, or jumping from one breakpoint to another, the currently executed line becomes un-highlighted, but the code never moves to the next line. No line is highlighted as the current line.
THe app on the device itself is frozen (as it usually is while debugging). The step into, step over and run buttons/commands are disabled. I have no choice but to stop debugging and try again.

It happens randomly, I could run the exact same build 5 times, and it could happen randomly on a different line of code each time.
Comment 1 Jeffrey Stedfast 2011-12-12 17:52:35 UTC
Dermot: when MonoDevelop 2.8.5 and MonoTouch 5.0.4 are released in the next few days, could you test those out and see if you can still reproduce this?

There's been a number of fixes to the debugger code.

I recognize that it's a "doesn't always happen" bug, so it'll likely take a few days of testing before you can feel sure that it's no longer an issue (assuming you don't reproduce it!), so no rush.

I'm going to mark as NEEDINFO for now since I've not seen this.
Comment 2 Dermot 2012-03-10 00:23:28 UTC
This seems to be narrowed down to when an exception occurs in a thread (such as a threadpool thread). There is no feedback that there was an error, the debugger just doesn't move to the next line
Comment 3 Dermot 2012-09-03 22:04:23 UTC
Ok, I've narrowed this down further. It seems to be occurrig the first time a method is called from a referenced dll.

Its pretty common. For every 10 times I start a debug, it might happen maybe 6 times. It really slows down development.
Comment 4 Dermot 2012-09-15 21:55:17 UTC
This is FAR far better than it used to be. It does still happen, but is much rarer.

	Mono 2.10.9 (tarball)
	GTK 2.24.10
	GTK# (
	Package version: 210090011
Apple Developer Tools:
	 Xcode 4.4.1 (1488)
	 Build 4F1003
Mono for Android: Not Installed

Monotouch: 5.4.0
Comment 5 Jeffrey Stedfast 2012-10-19 16:51:23 UTC
Thanks for keeping us updated.

I might need to get the runtime guys involved in this one.

Zoltan: any ideas?
Comment 6 Zoltan Varga 2012-10-19 19:37:04 UTC
Setting the env variable MONO_SDB_ENV_OPTIONS to 'loglevel=10' produces lots of debugging output on stdout, that might help in diagnosing the problem.
Comment 7 Jeffrey Stedfast 2013-06-06 14:54:33 UTC
Has this been fixed, by any chance?
Comment 8 Jeffrey Stedfast 2013-08-05 13:18:24 UTC
I've started to experience this lately myself...
Comment 9 Jeffrey Stedfast 2013-08-05 13:19:28 UTC
just as a reminder to myself: this doesn't seem to be iPhone related because I've been getting this behavior while debugging Xamarin Studio inside Xamarin Studio.
Comment 10 Jeffrey Stedfast 2014-10-07 15:40:43 UTC
haven't seen this in ages