With $config['db']['schemacheck'] set to 'script' in live deployment, Schema class wasn't being preloaded for us; the uses of TableDef by plugins for DataObject configuration would then fail because the class wasn't loaded. Broken to separate files, the autoloader can find all classes in either case.
PHP Fatal error: Class 'TableDef' not found in /var/www/statusnet/plugins/OpenID/User_openid.php on line 43, referer: http://identi.ca/brionv/all
Brion Vibber