I am using Drupal 7 on a CentOS 6.5 box. I am trying to debug some code which produces the following error:

User error: ImageMagick error 1: convert: no decode delegate for this image format /tmp/thesis-163.OBJ.xml' @ constitute.c/ReadImage/503. convert: missing an image filename jpg:/tmp/thesis-163.OBJ.PREVIEW.jpg' @ convert.c/ConvertImageCommand/2800. in _imagemagick_convert_exec() (line 519 of /var/www/html/sites/all/modules/imagemagick/imagemagick.module).

I can see that the problem is caused by the fact that ImageMagick is trying to make jpg out of a xml file. What the error is about, isn't really the issue. The issue is that, when I insert a dsm statement to check what is going and run the program again, the error goes away. If I comment out the dsm statement and run the program again the error returns. I have never seen this type of behaviour before and can't explain it.

Unfortunately, I can't reproduce this behavior with a small snippet of code otherwise I would post it here.

Can someone explain why this is happening so that I can fix it?

  • do you test dpm instead of dsm and the error exists?
    – Yuseferi
    Commented May 19, 2014 at 17:49
  • 1
    dsm maps to dsm, so should be: api.drupal.org/api/devel/devel.module/function/dsm/7
    – sanzante
    Commented May 19, 2014 at 19:23
  • @tunic s reply below seems really interesting, using dd is a great tip, and another possible reason might be the session (ie dpm putting stuff into the session) ? but it would probably really help to see at least a part of the code :)
    – mojzis
    Commented May 19, 2014 at 20:52
  • Sorry not an answer but you might have some luck using the object_log module which saves krumo to the database instead of printing to the screen. You can access it in the backend under Reports > Object Log
    – leexonline
    Commented May 20, 2014 at 0:14
  • @leexonline That sounds very interesting. I will give that a try.
    – user5013
    Commented May 20, 2014 at 23:33

2 Answers 2


You may be experiencing a Krumo side effect:


The problem is that PHP handles references to array elements in a risky way, see this article: PHP: References To Array Elements Are Risky

I haven't read the post deeply, and can't assure you have this problem, but you may try the workaround to see if it works: use Krumo NG.

Another way is to use dd to dump your traces to a file, see functions documentation: https://api.drupal.org/api/devel/devel.module/function/dd/7

  • Thanks for the useful links. I will give Krumo NG a try and see if it solves the problem.
    – user5013
    Commented May 22, 2014 at 15:36

May want to try one of these or some combination of them. Sometimes dsm gives me weird behavior and I have to resort to one of these.

print '<pre>' . print_r($your_item) . '</pre>';

print '<pre>' . dsm($your_item) . '</pre>';

drupal_set_message('<pre>' . print_r($your_item,true) . '</pre>');

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