Ok this is because bool(<element_instance) returns the value __len__() which is the _children attribute.


(Pdb) print d_[0].user and d_[0].user.email_link or None
None
(Pdb) print d_[0].user.email_link
<Element a at 4d78250>
(Pdb) print bool(d_[0].user.email_link)
False
(Pdb) len(d_[0].user.email_link)
0
(Pdb) len(d_[0].user.email_link._children)
0

http://gerrit.beaker-project.org/#/c/1670/

Verified with beaker-0.11.3-1.git.187.dac7008.el6.
While a system is using by a user, queue a job on it, user column is not empty now.

Beaker 0.12 has been released.