I've been playing around recently with CivicSpace, a Drupal-based software package using PHP and MySQL that includes features such as a blog, a calendar and an email list. After I did a test installation at a domain where I also have a test installation of MediaWiki running, I noticed a problem with MediaWiki. Whenever I tried to access the wiki as a logged-in user, I got the following error message:
Fatal error: session_start(): Failed to initialize storage module. in /usr/www/users/rampton/wiki/User.php on line 146
After some experimenting, I discovered that the problem arises because Drupal requires adding the the following lines to .htaccess to modify the PHP configuration:
php_value session.save_handler 'user' php_value session.cache_limiter none
Once I deleted those lines from .htaccess, the problem went away, and I was able to get both CivicSpace and the wiki running on the same server by simply putting a different .htaccess file in the directories for each package. However, I thought I should call this error message to the attention of developers here. If anyone ever wants to develop MediaWiki into a Drupal module, this conflict might give them some headaches.
--Sheldon Rampton