CiviCRM 5.13 upgrade breaks Drupal websites using HTMLPurifier module.
HTMLPurifier was updated in the CiviCRM 5.13 dependencies, including a change to the loading and bootstrap path.
On Drupal sites using the HTMLPurifier module &/ library, this causes a load error:
PHP message: PHP Fatal error: Cannot declare class HTMLPurifier_Bootstrap, because the name is already in use in /var/www/vhosts/**DOMAIN**/httpdocs/sites/all/libraries/htmlpurifier/library/HTMLPurifier/Bootstrap.php on line 30
Originally this appeared to be only affecting the update script, however Drupal front-end pages (e.g. Views) that bootstrap CiviCRM are also affected.
The impact of this problem can be variable:
- If the CiviCRM Database Upgrade script is being executed in the web browser, then this will abort mid-process and leave the database in an inconsistent state.
- CiviCRM Database Upgrade using drush will continue and succeed, however errors are logged.
- Drupal will white-screen and HTTP Error 500 on any CiviCRM integrated pages and views.
Agileware Ref: CIVICRM-1212