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Robert
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Breakpoints unpredictable in R2011a

Asked by Robert
on 21 Apr 2011
Since upgrading to R2011a, breakpoints in my code are unpredictable. Sometimes they work, and sometimes they don't. My code worked fine with breakpoints in R2010b. I don't have any "clear all" statements, and the breakpoints are still visible as red dots in my code. The code I'm using is on the MATLAB path, and there is only one copy.
Anyone else having difficulty with breakpoints in this latest release? Even better, anyone know how to fix it?

  11 Comments

Is there a bug report on this? I love the known bugs that are being investigate that are not listed as bugs.
This thing is starting to annoy me as well
What I do is:
click to clear > click to place the breakpoint back > save .m file
This is frankly, outrageous, yet true!!

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6 Answers

Answer by TB
on 21 Sep 2011
 Accepted Answer

The official word I got from The Mathworks is that it is fixed in R2011b, but no workaround for R2011a.

  6 Comments

Jan
on 22 Sep 2011
Fine, now it is a documented bug. Nevertheless it remains a bug and will not be fixed although it concerns the elementary functionality of MATLAB 2011a. This reduces the value of this release dramatically.
Robert
on 22 Sep 2011
Agreed. Suppose I only have 2011a, without money to buy a new release. Then I'm stuck with a buggy, useless program. If Mathworks sells me software with a bug, they should not then tell me, "Oh, by the way, if you want this to work correctly you have to pay even more."
While I am all for venting and in my opinion it is fine to vent here, nobody who can do anything is listening (not quite, but you get the idea). Go through the official channel of customer support to let them know how you feel.

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Answer by Alexander Kosenkov on 31 Aug 2011

Extremely annoying bug, since R2011a. Breakpoints have their own lives, regardless of user actions. Just doesn't work.
As workaround, sometimes, it helps to modify file (add and remove space) and then saving it again. Otherwise I have to restart Matlab (obviously loosing all breakpoints). Clicking 'Clear all breakpoints in all files' and then setting breakpoints again - does not help for me.
Anyone here from Mathworks to comment?

  1 Comment

Robert
on 31 Aug 2011
This bug makes the R2011 versions useless to me. Maybe it's my own fault for writing software that needs debugging in the first place, but until the debugging feature works properly I'm sticking with R2010b.
Would love to know when the issue is fixed, if indeed it is a known issue as Friedrich claims above.

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Answer by Andreas Goser on 22 Sep 2011

One user pointed me to this thread, as we were discussing aspects of the development timelines and fixing bugs. Indeed, MathWorks fixes bugs in the release under development and not by default for all affected older releases. But certainly, it is possible. And it happens. Please see the recent Service Pack releases. Those are responses on a number of (typically significant) bugs. In short, this is dependent on impact, frequeny and whether accpetable workarounds are available or not. I can just encourage you to describe the impact to Technical Support, so that they can provide this information to Development. You may think the impact is obvious? It is not.

  3 Comments

Jan
on 22 Sep 2011
Thanks for this comment.
I see the problem of the efficient communication of bugs. It is a big challenge for the technical support to filter the high impact problems from the noise of "EVAL does not work as expected" messages. Sometimes the support team is a little bit stubborn (if this term has a negative connotation: sorry, meant more neutrally - I'm not a native speaker), but they *never* left me alone with a problem until I confirmed that it is solved.
I think, this forum is helpful to improve the communication with the technical support: a discussion with other users helps to reduce the noise. If the bug-report contains a rough overview about the number of affected users (e.g. "<10" "<100" etc) and a tiny description of the underlying cause of the bug, it would be easier to estimate, if this is a strange exception or a general lack or quality. "This bug was fixed as of R2011b(7.13)" is not a very encouraging feedback of the feedback.
This is the first I have heard of the service pack releases ??
Jan
on 22 Sep 2011
@Walter: Go to http://en.wikipedia.org/wiki/MATLAB and look for the "Release history". There are 2 SPs sincs 2006.

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Answer by Lucas García on 31 Aug 2011

Hi Robert,
I haven't been able to reproduce this issue, but I have heard it from other users, so that makes it empirically a possible bug in R2011a. In any case, I will recommend that you report it to the Technical Support team mentioning your problem with as much detail as you can.
When you are debugging and type dbstatus, are the true breakpoint lines listed?
As a possible workaround, I will try the following:
>> feature accel off
>> feature jit off

  1 Comment

Jan
on 22 Sep 2011
It cannot be called "workaround" to disable the JIT acceleration. Some of the loops will need 100 times more processing time, such that a program can become completely useless even if it only concerns the debugging.

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Answer by Sean de Wolski
on 21 Apr 2011

Are you calling it in cell mode by clicking "Evaluate Cell"?

  6 Comments

Robert
on 6 May 2011
As I said, there is only one copy of this file.
And yes, the file is writable. If it was unwritable and that was causing problems, the breakpoints would never work. As I said, I'll hit run and they don't work, then I hit run again and they do work.
Jan
on 8 Jun 2011
Any CLEAR ALL hidden in a subfunction?!
SK
on 9 Jun 2011
Definitely no CLEAR ALL in my code. And the file is writable, too.

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Answer by Adam
on 2 May 2012

I didn't know this, maybe everyone else did...
The Matlab statement:
clear all
clears breakpoints. So if you have "clear all" in your script, any breakpoints after that line will be cleared before script execution reaches them, so Matlab won't break. Getting rid of this line was the solution in my case, but it may not work in every case.
[opinion] this functionality is DUMB and should be fixed. [/opinion]

  2 Comments

Robert
on 2 May 2012
Quote from original post:
> I don't have any "clear all" statements
The solution was to stick with R2010b, or to wait for R2011b.
But agreed, it would be nice to have a "clear all but breakpoints" command.
Jan
on 2 May 2012
Has this problem been fixed in the service pack2 for 2010b?

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