I upgraded two Joomla sites from 5.8.x to 5.9 and one of them now gives an error for anonymous contributions or membership registrations:
Error:
Database Error Code: Cannot add or update a child row: a foreign key constraint fails (`zzz`.`civicrm_acl_contact_cache`, CONSTRAINT `FK_civicrm_acl_contact_cache_user_id` FOREIGN KEY (`user_id`) REFERENCES `civicrm_contact` (`id`) ON DELETE CASCADE), 1452
Additional Details:
Array ( [callback] => Array ( [0] => CRM_Core_Error [1] => handle )
[code] => -3
[message] => DB Error: constraint violation
[mode] => 16
[debug_info] => INSERT INTO civicrm_acl_contact_cache ( user_id, contact_id, operation ) VALUES(0, 0, 'View') [nativecode=1452 ** Cannot add or update a child row: a foreign key constraint fails (`zzz`.`civicrm_acl_contact_cache`, CONSTRAINT `FK_civicrm_acl_contact_cache_user_id` FOREIGN KEY (`user_id`) REFERENCES `civicrm_contact` (`id`) ON DELETE CASCADE)]
[type] => DB_Error
[user_info] => INSERT INTO civicrm_acl_contact_cache ( user_id, contact_id, operation ) VALUES(0, 0, 'View') [nativecode=1452 ** Cannot add or update a child row: a foreign key constraint fails (`zzz`.`civicrm_acl_contact_cache`, CONSTRAINT `FK_civicrm_acl_contact_cache_user_id` FOREIGN KEY (`user_id`) REFERENCES `civicrm_contact` (`id`) ON DELETE CASCADE)]
[to_string] => [db_error: message="DB Error: constraint violation" code=-3 mode=callback callback=CRM_Core_Error::handle prefix="" info="INSERT INTO civicrm_acl_contact_cache ( user_id, contact_id, operation ) VALUES(0, 0, 'View') [nativecode=1452 ** Cannot add or update a child row: a foreign key constraint fails (`zzz`.`civicrm_acl_contact_cache`, CONSTRAINT `FK_civicrm_acl_contact_cache_user_id` FOREIGN KEY (`user_id`) REFERENCES `civicrm_contact` (`id`) ON DELETE CASCADE)]"]
)
This matches a similar issue after 5.9.0 upgrade: DB Error: constraint violation on anonymous user event registration after 5.8.2 -> 5.9.0 update
I have Mail enabled. The error doesn't occur when logged in so I've matched and then enabled more permissions than the other site which works, but it makes no difference.
