[Sqlalchemy-tickets] [sqlalchemy] #2885: reduce for proxied columns when syncing between mappers

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

#2885: reduce for proxied columns when syncing between mappers
--------------------+---------------------------------------
 Reporter:  zzzeek  |           Owner:  zzzeek
     Type:  defect  |          Status:  new
 Priority:  high    |       Milestone:  0.9.0
Component:  orm     |        Severity:  minor - half an hour
 Keywords:          |  Progress State:  needs tests
--------------------+---------------------------------------
 this is probably for backport to 0.8 as well

 {{{
 #!python
 from sqlalchemy import select, Table, Column, Integer, ForeignKey,
 create_engine, Text, Float
 from sqlalchemy.orm import Session
 from sqlalchemy.ext.declarative import declarative_base

 Base = declarative_base()

 class Person(Base):
     __table_actual__ = Table('person', Base.metadata,
                              Column('id', Integer, primary_key=True),
                              Column('name', Text),
                              Column('type', Text)
                              )
     __table__ = select([__table_actual__]).alias("person_alias")

     __mapper_args__ = {"polymorphic_on": __table__.c.type,
 "polymorphic_identity": "Person"}

 class Golfer(Person):
     __tablename__ = "golfer"
     id_person = Column(Integer, ForeignKey(Person.__table_actual__.c.id),
 primary_key=True)
     handicap = Column(Float)
     __mapper_args__ = {"polymorphic_identity": "Golfer"}

 engine = create_engine('sqlite://', echo=True)
 Base.metadata.create_all(engine)
 session = Session(engine)

 p1 = Person(name="Joe Bloggs")
 session.add(p1)

 g1 = Golfer(name="Tiger Woods", handicap=2.5)
 session.add(g1)
 session.commit()

 print(g1.name)
 }}}

 patch:

 {{{
 #!diff
 diff --git a/lib/sqlalchemy/orm/mapper.py b/lib/sqlalchemy/orm/mapper.py
 index b3b872f..bdaeca0 100644
 --- a/lib/sqlalchemy/orm/mapper.py
 +++ b/lib/sqlalchemy/orm/mapper.py
 @@ -2488,7 +2488,8 @@ class Mapper(_InspectionAttr):
              for m in self.iterate_to_root():
                  if m._inherits_equated_pairs and \
                      cols.intersection(
 -                        [l for l, r in m._inherits_equated_pairs]):
 +                        util.reduce(set.union,
 +                          [l.proxy_set for l, r in
 m._inherits_equated_pairs])):
                      result[table].append((m, m._inherits_equated_pairs))

          return result
 }}}

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Ticket URL: <http://www.sqlalchemy.org/trac/ticket/2885>
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