[Sqlalchemy-tickets] [sqlalchemy] #2741: uselist=False collection not backref deferred, leads to unwanted load/autoflush

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

#2741: uselist=False collection not backref deferred, leads to unwanted
load/autoflush
---------------------+------------------------------------
 Reporter:  zzzeek   |           Owner:  zzzeek
     Type:  defect   |          Status:  new
 Priority:  highest  |       Milestone:  0.8.xx
Component:  orm      |        Severity:  major - 1-3 hours
 Keywords:           |  Progress State:  in queue
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 {{{
 #!python
 from sqlalchemy import *
 from sqlalchemy.orm import *
 from sqlalchemy.ext.declarative import declarative_base

 Base = declarative_base()

 class A(Base):
     __tablename__ = 'a'

     id = Column(Integer, primary_key=True)
     b = relationship("B", uselist=False, backref="a")

 class B(Base):
     __tablename__ = 'b'

     id = Column(Integer, primary_key=True)
     a_id = Column(Integer, ForeignKey('a.id'), nullable=False)

 e = create_engine("sqlite://", echo=True)
 Base.metadata.create_all(e)

 sess = Session(e)

 a1 = A()
 b1 = B(a=a1)
 sess.add(a1)

 a2 = A()
 sess.add(a2)

 sess.commit()

 b1 = sess.query(B).first()

 # this is needed to trigger it
 b1.a


 b1.a = a2
 }}}

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Ticket URL: <http://www.sqlalchemy.org/trac/ticket/2741>
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