[Sqlalchemy-tickets] [sqlalchemy] #2761: allow non-property objects to work with declarative string resolution

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

#2761: allow non-property objects to work with declarative string resolution
-------------------------+---------------------------------------
 Reporter:  zzzeek       |           Owner:  zzzeek
     Type:  enhancement  |          Status:  new
 Priority:  high         |       Milestone:  0.8.xx
Component:  orm          |        Severity:  minor - half an hour
 Keywords:               |  Progress State:  needs tests
-------------------------+---------------------------------------
 {{{
 #!python
 from sqlalchemy import Column, Integer, String, ForeignKey, case
 from sqlalchemy.ext.declarative import declarative_base
 from sqlalchemy.ext.hybrid import hybrid_property
 from sqlalchemy.orm import relationship

 Base = declarative_base()


 class User(Base):
     __tablename__ = 'user'
     id = Column(Integer, primary_key=True)
     firstname = Column(String(50))
     lastname = Column(String(50))
     game_id = Column(Integer, ForeignKey('game.id'))

     @hybrid_property
     def fullname(self):
         if self.firstname is not None:
             return self.firstname + " " + self.lastname
         else:
             return self.lastname

     @fullname.expression
     def fullname(cls):
         return case([
             (cls.firstname != None, cls.firstname + " " + cls.lastname),
         ], else_=cls.lastname)


 class Game(Base):
     __tablename__ = 'game'
     id = Column(Integer, primary_key=True)
     name = Column(String(50))
     users = relationship("User", order_by="User.fullname")

 if __name__ == '__main__':
     game = Game(name="tetris")
 }}}

 patch:

 {{{
 #!diff
 diff --git a/lib/sqlalchemy/ext/declarative/clsregistry.py
 b/lib/sqlalchemy/ext/declarative/clsregistry.py
 index 95aba93..a669e37 100644
 --- a/lib/sqlalchemy/ext/declarative/clsregistry.py
 +++ b/lib/sqlalchemy/ext/declarative/clsregistry.py
 @@ -12,7 +12,7 @@ This system allows specification of classes and
 expressions used in
  from ...orm.properties import ColumnProperty, RelationshipProperty, \
                              SynonymProperty
  from ...schema import _get_table_key
 -from ...orm import class_mapper
 +from ...orm import class_mapper, interfaces
  from ... import util
  from ... import exc
  import weakref
 @@ -190,19 +190,21 @@ class _GetColumns(object):
      def __getattr__(self, key):
          mp = class_mapper(self.cls, configure=False)
          if mp:
 -            if not mp.has_property(key):
 +            if key not in mp.all_orm_descriptors:
                  raise exc.InvalidRequestError(
                              "Class %r does not have a mapped column named
 %r"
                              % (self.cls, key))

 -            prop = mp.get_property(key)
 -            if isinstance(prop, SynonymProperty):
 -                key = prop.name
 -            elif not isinstance(prop, ColumnProperty):
 -                raise exc.InvalidRequestError(
 -                            "Property %r is not an instance of"
 -                            " ColumnProperty (i.e. does not correspond"
 -                            " directly to a Column)." % key)
 +            desc = mp.all_orm_descriptors[key]
 +            if desc.extension_type is interfaces.NOT_EXTENSION:
 +                prop = desc.property
 +                if isinstance(prop, SynonymProperty):
 +                    key = prop.name
 +                elif not isinstance(prop, ColumnProperty):
 +                    raise exc.InvalidRequestError(
 +                                "Property %r is not an instance of"
 +                                " ColumnProperty (i.e. does not
 correspond"
 +                                " directly to a Column)." % key)
          return getattr(self.cls, key)


 }}}

--
Ticket URL: <http://www.sqlalchemy.org/trac/ticket/2761>
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