and mess up your Drupal site "permanently". Not Really.
I screwed up my Drupal project one day by copying my modules directory and forgetting to move it out of it's parent directory. Details are unimportant.
The point is, I cleared my cache and did a few other things and Drupal started looking for modules in a location that was unavailable. Needless to say (I hope needless anyway), the system and registry tables were out of sync with some of the modules.
Fixing (or so I thought) the registry table manually was unsuccessful.
Long story short, thank you Apollo Tang provided the following script on this page.
<?php // $Id$ /** * @file * Rescue script that rebuilds the code registry in the event of Drupal not * being able to do a full bootstrap due to a corrupt/lost code registry. * One cause of a bad registry is modules being moved to a new location. * * Run from the root directory of the Drupal installation. */ /** * Root directory of Drupal installation. */ define('DRUPAL_ROOT', getcwd()); $defaults = array( 'HTTP_HOST' => 'localhost', 'PHP_SELF' => '/index.php', 'QUERY_STRING' => '', 'REQUEST_URI' => '/', 'SCRIPT_NAME' => NULL, 'REMOTE_ADDR' => '127.0.0.1', 'REQUEST_METHOD' => 'GET', 'SERVER_NAME' => NULL, 'SERVER_SOFTWARE' => NULL, 'HTTP_USER_AGENT' => 'console', ); // Replace elements of the $_SERVER array, as appropriate. $_SERVER = $_SERVER + $defaults; require_once DRUPAL_ROOT . '/includes/bootstrap.inc'; require_once DRUPAL_ROOT . '/includes/entity.inc'; require_once DRUPAL_ROOT . '/includes/common.inc'; require_once DRUPAL_ROOT . '/modules/system/system.module'; require_once DRUPAL_ROOT . '/includes/database/select.inc'; drupal_bootstrap(DRUPAL_BOOTSTRAP_FULL); registry_rebuild(); ?>
Use in good health. and don't screw up your modules directory.