[Sqlalchemy-tickets] [sqlalchemy] #2828: column_property hides original column

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

#2828: column_property hides original column
-----------------------------+-----------------------------------------
 Reporter:  jerryji          |           Owner:  zzzeek
     Type:  defect           |          Status:  new
 Priority:  medium           |       Milestone:
Component:  orm              |        Severity:  no triage selected yet
 Keywords:  column_property  |  Progress State:  awaiting triage
-----------------------------+-----------------------------------------
 column_property hides original column from __mapper__ when used with no
 change.

 Results from running the attached column_property.py, tested against
 sqlalchemy git clone just now --

 {{{
 (sqlalchemy) C:\sqlalchemy>ipython
 Python 2.7.5 (default, May 15 2013, 22:44:16) [MSC v.1500 64 bit (AMD64)]

 In [1]: import sqlalchemy
 In [2]: sqlalchemy.__version__
 Out[2]: '0.9.0'

 In [3]: %run column_property.py
 ['name_alias', 'id']
 ['name_alias', 'id', 'name']
 }}}

 column_property.py (in case attachment fails), maybe not the right way to
 create an aliasing column, but still looks like a bug to me --

 {{{
 from sqlalchemy import (
     create_engine,
     Column,
     Text,
     Integer,
 )
 from sqlalchemy.orm import (
     scoped_session,
     sessionmaker,
     column_property,
 )
 from sqlalchemy.ext.declarative import declarative_base

 Base = declarative_base()

 class NameMissing(Base):
     __tablename__ = 'name_missing'
     id = Column(Integer, primary_key=True)
     name = Column(Text)
     name_alias = column_property(name)

     def __init__(self, id, name):
         self.id = id
         self.name = name

 class NameOK(Base):
     __tablename__ = 'name_ok'
     id = Column(Integer, primary_key=True)
     name = Column(Text)
     name_alias = column_property(name+'')

     def __init__(self, id, name):
         self.id = id
         self.name = name

 engine = create_engine('sqlite://')
 Base.metadata.create_all(engine)
 dbsession = scoped_session(sessionmaker(bind=engine))
 new_name_missing = NameMissing(1, 'foobar')
 dbsession.add(new_name_missing)
 new_name_ok = NameOK(1, 'foobar')
 dbsession.add(new_name_ok)
 dbsession.commit()

 name_missing = dbsession.query(NameMissing).first()
 print name_missing.__mapper__.columns.keys()

 name_ok = dbsession.query(NameOK).first()
 print name_ok.__mapper__.columns.keys()
 }}}

 Jerry

--
Ticket URL: <http://www.sqlalchemy.org/trac/ticket/2828>
sqlalchemy <http://www.sqlalchemy.org/>
The Database Toolkit for Python