Redmine

This happens in the current version of redmine from git (svn r13129), with mysql 14.14.

1. Create an issue
2. Create a copy of that issue
3. Attempt to create a relation between the issues (e.g. set the copy to FOLLOW the original)

An error will occur:

ActiveRecord::RecordNotUnique (Mysql2::Error: Duplicate entry '31-40' for key 'index_issue_relations_on_issue_from_id_and_issue_to_id': INSERT INTO `issue_relations` (`delay`, `issue_from_id`, `issue_to_id`, `relation_type`) VALUES (0, 31, 40, 'precedes')):
app/controllers/issue_relations_controller.rb:48:in `create'

This index effectively prevents you from creating two relations between the same pair of issues. Shouldn't this combination of relationships be ok?