mantisbt/mantisbt — comment on commit 94f414370575d552d05330a1e08284a115c2ecc7
File:  line 0
By atrol:

Really?
I didn't have a deeper look but have a look at the signature of the function tag_bug_detach, user_id is the fourth parameter.
function tag_bug_detach( $p_tag_id, $p_bug_id, $p_add_history = true, $p_user_id = null )