Clearing the theme registry

Before we begin, we need to familiarize ourselves with a seemingly trivial yet crucial task that needs to be performed on a routine basis during theme development—clearing the theme registry. The theme registry is essentially a table that Drupal uses to list and track the files and features of a theme, as well as the theme functions which are being exposed by modules and the theme itself.

While it is recommended practice to turn on Drupal's cache feature only for production sites, the theme registry is built and cached regardless of other caching options. As a result, any changes that affect the structure of the theme will necessitate the clearing of the theme registry.

Getting ready

Rebuilding the registry is an intensive operation which is required only when changes have been made to the theme's files.

How to do it...

There are a number of ways of clearing the registry. In a stock Drupal installation, visiting admin/settings/performance (Home | Administer | Site...