Bug 10873 - [CorDebugger] Inspecting a DataSet variable shows "Evaluation failed: System.NullReferenceException"
Summary: [CorDebugger] Inspecting a DataSet variable shows "Evaluation failed: System....
Alias: None
Product: Xamarin Studio
Classification: Desktop
Component: Debugger ()
Version: 4.0
Hardware: PC Windows
: --- normal
Target Milestone: 4.2.3 (from master)
Assignee: Bugzilla
Depends on:
Reported: 2013-03-04 07:20 UTC by Miha Markic
Modified: 2014-01-07 05:04 UTC (History)
3 users (show)

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

tooltip error (2.50 KB, image/png)
2013-03-04 07:20 UTC, Miha Markic

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Description Miha Markic 2013-03-04 07:20:14 UTC
Created attachment 3530 [details]
tooltip error

Xamarin Studio 2.0

Hover over ds variable after this line is executed: 
DataSet ds = new DataSet();

The value tooltip will show "Evaluation failed: System.NullReferenceException" instead of normal object tooltip.
Comment 1 Jeffrey Stedfast 2013-03-05 15:00:18 UTC
Do you have a small test case so that I can reproduce this?

I'm not able to reproduce this with a small test program that just has the above line (and a Console.WriteLine() right after it).
Comment 2 Miha Markic 2013-03-05 16:02:50 UTC
That's enough code for me - just create a DataSet instance and inspect the variable.
Note that I am running Xamarin Studio on Windows x64 (7 and 8) without mono framework.

I've also attached a debugger and stopped on that exception.

Mono.Debugging.Evaluation.EvaluatorException occurred
  Message=Evaluation failed: System.NullReferenceException
       at MonoDevelop.Debugger.Win32.CorDebuggerSession.RuntimeInvoke(CorEvaluationContext ctx, CorFunction function, CorType[] typeArgs, CorValue thisObj, CorValue[] arguments)
Comment 3 Jeffrey Stedfast 2013-03-05 16:13:15 UTC
Ah, that explains it: I've been testing with the Mono backend on Mac.

The CorDebugger backend is really really really broken. If you can, I suggest debugging with the Mono backend instead.
Comment 4 Miha Markic 2013-03-06 02:11:21 UTC
So, does it make sense to bother with CorDebugger bugs at all?
Comment 5 Jeffrey Stedfast 2013-03-06 07:17:10 UTC
You mean submitting them? I don't mind if you find/submit more CorDebugger bugs as it would be good to keep track of them so that either we or a contributor can fix them.
Comment 6 Marius Ungureanu 2013-09-08 07:58:15 UTC
This issue has been fixed and will be included in future releases.
Comment 7 Sadik Ali 2014-01-07 04:51:16 UTC
I have verified this issue and not getting "Evaluation failed: System.NullReferenceException". following are the steps:

1. Created a sample iOS project.
2. Added below code:

DataSet ds = new DataSet()
String str = ds.DataSetName

3. apply beak point at "Console.WriteLine(str)" line
4. Debug application.

Refer Screen shot: http://screencast.com/t/vIuM8zDkWXo3

Checked With:

All Mac
XS 4.2.3 (build 24)
Comment 8 Sadik Ali 2014-01-07 05:04:41 UTC
Also I have verified on machine with following steps:

1. Created console application.
2. Added above my comment code.
3. Apply break point 
4. Debug application and not getting issue.

Refer screen shot: http://screencast.com/t/f66jk44FTtaS

Checked With:

Window 8
XS 4.2.3 (build 23)