[Sqlalchemy-tickets] [sqlalchemy] #1018: Polymorphic relationships fail in a concrete table inheritance scenario

[sqlalchemy <mi...@zz...>]

#1018: Polymorphic relationships fail in a concrete table inheritance scenario
--------------------+-------------------------------------------------------
 Reporter:  ged     |          Owner:  zzzeek                
     Type:  defect  |         Status:  new                   
 Priority:  medium  |      Milestone:                        
Component:  orm     |       Severity:  no triage selected yet
 Keywords:          |   Status_field:  awaiting triage       
--------------------+-------------------------------------------------------
 See attached test case (which is a modified version of
 test/orm/inheritance/concrete.py).

 Here is the traceback.
 {{{
   File "/home/ged/concrete_with_relations.py", line 188, in
 test_relation_2
     res = session.query(Company).one().engineers
   File "/home/ged/devel/sqlalchemy/trunk/lib/sqlalchemy/orm/query.py",
 line 921, in one
     ret = list(self[0:2])
   File "/home/ged/devel/sqlalchemy/trunk/lib/sqlalchemy/orm/query.py",
 line 985, in iterate_instances
     rows = [process[0](context, row) for row in fetch]
   File "/home/ged/devel/sqlalchemy/trunk/lib/sqlalchemy/orm/query.py",
 line 1543, in main
     extension=context.extension, only_load_props=context.only_load_props,
 refresh_instance=context.refresh_instance
   File "/home/ged/devel/sqlalchemy/trunk/lib/sqlalchemy/orm/mapper.py",
 line 1435, in _instance
     self.populate_instance(context, instance, row,
 only_load_props=only_load_props, instancekey=identitykey, isnew=isnew)
   File "/home/ged/devel/sqlalchemy/trunk/lib/sqlalchemy/orm/mapper.py",
 line 1500, in populate_instance
     selectcontext.exec_with_path(self, key, populator, instance, row,
 ispostselect=ispostselect, isnew=isnew, **flags)
   File "/home/ged/devel/sqlalchemy/trunk/lib/sqlalchemy/orm/query.py",
 line 1664, in exec_with_path
     return fn(*args, **kwargs)
   File
 "/home/ged/devel/sqlalchemy/trunk/lib/sqlalchemy/orm/strategies.py", line
 622, in execute
     self.mapper._instance(selectcontext, decorated_row, result_list)
   File "/home/ged/devel/sqlalchemy/trunk/lib/sqlalchemy/orm/mapper.py",
 line 1359, in _instance
     return mapper._instance(context, row, result=result,
 polymorphic_from=self)
   File "/home/ged/devel/sqlalchemy/trunk/lib/sqlalchemy/orm/mapper.py",
 line 1435, in _instance
     self.populate_instance(context, instance, row,
 only_load_props=only_load_props, instancekey=identitykey, isnew=isnew)
   File "/home/ged/devel/sqlalchemy/trunk/lib/sqlalchemy/orm/mapper.py",
 line 1484, in populate_instance
     poly_select_loader = self._get_poly_select_loader(selectcontext, row)
   File "/home/ged/devel/sqlalchemy/trunk/lib/sqlalchemy/orm/mapper.py",
 line 1522, in _get_poly_select_loader
     cond, param_names =
 self._deferred_inheritance_condition(hosted_mapper, needs_tables)
   File "/home/ged/devel/sqlalchemy/trunk/lib/sqlalchemy/orm/mapper.py",
 line 1587, in _deferred_inheritance_condition
     allconds.append(visitors.traverse(mapper.inherit_condition,
 clone=True, visit_binary=visit_binary))
   File "/home/ged/devel/sqlalchemy/trunk/lib/sqlalchemy/sql/visitors.py",
 line 181, in traverse
     return vis.traverse(clause, clone=clone)
   File "/home/ged/devel/sqlalchemy/trunk/lib/sqlalchemy/sql/visitors.py",
 line 73, in traverse
     return self._cloned_traversal(obj)
   File "/home/ged/devel/sqlalchemy/trunk/lib/sqlalchemy/sql/visitors.py",
 line 108, in _cloned_traversal
     return self._cloned_traversal_impl(obj, util.Set(stop_on), {},
 _clone_toplevel=True)
   File "/home/ged/devel/sqlalchemy/trunk/lib/sqlalchemy/sql/visitors.py",
 line 115, in _cloned_traversal_impl
     elem = self._clone_element(elem, stop_on, cloned)
   File "/home/ged/devel/sqlalchemy/trunk/lib/sqlalchemy/sql/visitors.py",
 line 101, in _clone_element
     cloned[elem] = elem._clone()
 AttributeError: 'NoneType' object has no attribute '_clone'
 }}}

-- 
Ticket URL: <http://www.sqlalchemy.org/trac/ticket/1018>
sqlalchemy <http://www.sqlalchemy.org/>
The Database Toolkit for Python