Re: [Sqlalchemy-tickets] [sqlalchemy] #2887: subqueryload query invokes ahead of parent loader init, can cause conflicts

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

#2887: subqueryload query invokes ahead of parent loader init, can cause conflicts
------------------------------+-------------------------------
      Reporter:  zzzeek       |      Owner:  zzzeek
          Type:  defect       |     Status:  new
      Priority:  high         |  Milestone:  0.8.xx
     Component:  orm          |   Severity:  major - 1-3 hours
    Resolution:               |   Keywords:
Progress State:  in progress  |
------------------------------+-------------------------------

Comment (by zzzeek):

 at least some of the tests that fail are because they rely upon
 subqueryload to emit its query and load further related objects, even when
 the lead object otherwise is not subject to any row processing at all:

 {{{
         u1 =
 sess.query(User).filter_by(id=7).options(subqueryload("orders")).one()

         # id=7 is already loaded, no row processing for this User will
 take effect.
         # but we still want orders.items to get populated on the existing
 orders.
 sess.query(User).filter_by(id=7).options(subqueryload_all("orders.items")).first()
         assert 'items' in u1.orders[0].__dict__
 }}}

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Ticket URL: <http://www.sqlalchemy.org/trac/ticket/2887#comment:1>
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