[Sqlalchemy-tickets] [sqlalchemy] #2733: using backref raises AttributeError when querying column-based entities [declarative extension]

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

#2733: using backref raises AttributeError when querying column-based entities
[declarative extension]
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 Reporter:  andrija      |           Owner:  zzzeek
     Type:  defect       |          Status:  new
 Priority:  lowest       |       Milestone:
Component:  declarative  |        Severity:  no triage selected yet
 Keywords:               |  Progress State:  awaiting triage
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 [both sqlalchemy 0.8.1 and default branch / Python 2.7.3 / Ubuntu 12.04]

 Addressing "backref" attribute will raise an !AttributeError in case of
 querying column-based entities (`Child.parents` is specified with backref
 in `Parent` class):

 {{{session.query(Child.id).join(Child.parents)}}}

 This will not raise exception if `Child` or `Parent` entities are used in
 a query before.

 See the attached code for the full example.

 I'm not sure if this is a bug or should be expected behaviour. I haven't
 tried to reproduce it without declarative extension.

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Ticket URL: <http://www.sqlalchemy.org/trac/ticket/2733>
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