[web2py] empty list:reference seems like a bug

[LightOfMooN]

It's a problem, that if i have empty list:reference, the standard
database administration don't work because of wrong query:

Traceback (most recent call last):
  File "/home/www-data/web2py/gluon/restricted.py", line 188, in
restricted
    exec ccode in environment
  File "/home/www-data/web2py/applications/funportal/views/
appadmin.html", line 191, in <module>
    <p>
  File "/home/www-data/web2py/gluon/sqlhtml.py", line 1349, in
__init__
    r = field.represent(r)
  File "/home/www-data/web2py/gluon/dal.py", line 3113, in
list_ref_repr
    refs = r._db(r.id.belongs(ids)).select(r.id)
  File "/home/www-data/web2py/gluon/dal.py", line 4507, in select
    return self.db._adapter.select(self.query,fields,attributes)
  File "/home/www-data/web2py/gluon/dal.py", line 1003, in select
    rows = response(sql)
  File "/home/www-data/web2py/gluon/dal.py", line 994, in response
    self.execute(sql)
  File "/home/www-data/web2py/gluon/dal.py", line 1067, in execute
    return self.log_execute(*a, **b)
  File "/home/www-data/web2py/gluon/dal.py", line 1064, in log_execute
    return self.cursor.execute(*a,**b)
ProgrammingError: syntax error at or near ")"
LINE 1: SELECT  tag.id FROM tag WHERE (tag.id IN ());