CiviCRM Community Forums (archive)

Hmm, that error probably means that 'require_once' isn't actually requiring the class a single time -- the file is probably loaded multiple times.

A few questions/ideas:

a) Which CMS?

b) When you print debug_backtrace(), could you also print get_include_path()? Examine the list to see if there are two versions of Civi.

c) Are you doing anything funny with symlinks which might make it possible for one file ("CRM/Core/ClassLoader.php") to appear with two different paths? (I had a similar problem once when cobbling together CiviCRM from SVN with WordPress -- because I tried using symlinks to put it together.)

d) Are you using any custom modules or scripts which might bootstrap CiviCRM in their own way? (e.g. scripts which include civicrm.settings.php directly or xavier's class.api.php)

OK, problem found and fixed.  Adding this code to the top of CRM/Core/ClassLoader.php shows some interesting results:
foreach (get_included_files() as $file) {
  echo "$file<BR>";
}

With this I can see that there is indeed an extra copy of civicrm code under sites/all/modules/civicrm.trunk, which sits right next to the actual civicrm module code in sites/all/modules/civicrm.  The file sites/all/modules/civicrm.trunk/ClassLoader.php file was indeed being included, and then again the file sites/all/modules/civicrm/ClassLoader.php was being included too.

Not sure how or why that happens, but I just removed that extra directory and fixed the problem.

Thanks for the help, Tim.

I've also seen similar errors to this when using an opcode cache such as XCache. It occurs when the cache runs out of space; I had to double mine from 64Mb to 128Mb.

so I just started getting this error... in an erm "complex" sandbox environment...

for the me the answer seems to have been a simple drupal variable clear:

    drush @contact-qld vset civicrm_class_loader ''


initially I tried this with no joy:

    echo get_include_path();

then replacing

  require_once 'CRM/Core/ClassLoader.php';

with

    if (!class_exists('CRM_Core_ClassLoader')) {
      require_once 'CRM/Core/ClassLoader.php';
    }

but still only pain...

then in modules/contrib/civicrm/drupal/civicrm.module I found this:

 310 /**
 311  * Find & register classloader and store location in Drupal variable.
 312  * Per CRM-13737 this allows for drupal code to be outside the core directory
 313  * which makes it easier for sites managing their own installation methods that
 314  * may need to cover different drupal versions
 315  */
 316 function _civicrm_registerClassLoader() {
 317   $path = variable_get('civicrm_class_loader');
 318   if (empty($path) || !file_exists($path)) {
 319     $candidates = array(
 320         dirname(__FILE__) . '/../CRM/Core/ClassLoader.php',
 321         dirname(__FILE__) . '/../civicrm-core/CRM/Core/ClassLoader.php',
 322         dirname(__FILE__) . '/../core/CRM/Core/ClassLoader.php',
 323         // ... ad nauseum ...
 324     );
 325     foreach ($candidates as $candidate) {
 326       if (file_exists($candidate)) {
 327         $path = $candidate;
 328         variable_set('civicrm_class_loader', $candidate);
 329         break;
 330       }
 331     }
 332   }
 333
 334   require_once $path;
 335   CRM_Core_ClassLoader::singleton()->register();
 336 }

I've been removing the require_once in civicrm.settings.php for a while now. Erichs command removes the variable 'civicrm_class_loader' - stored in the variable table. His site name is configured to have an alias of @contact-qld