support @declared_attr as standalone getter? or just set up __tablename__, others explicitly

[Pieter Mulder]

The following code works without any problems in sqlalchemy 0.9.9 but fails in 1.0.0b1:

import sqlalchemy as sa
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy.ext.declarative import declared_attr


Base = declarative_base()


class Abstract1(object):

    @declared_attr
    def __tablename__(cls):
        return cls.__name__.lower()


class Concrete1(Abstract1, Base):
    id = sa.Column(sa.Integer, primary_key=True)


Abstract1.__tablename__
Concrete1.__tablename__

The exception:

#!
<ipython-input-8-1445e04c4c3b> in <module>()
----> 1 Concrete1.__tablename__

/home/pieter/.virtualenvs/proigia_encryption/lib/python2.7/site-packages/sqlalchemy/ext/declarative/api.pyc in __get__(desc, self, cls)
    180         except KeyError:
    181             raise exc.InvalidRequestError(
--> 182                 "@declared_attr called outside of the "
    183                 "declarative mapping process; is declarative_base() being "
    184                 "used correctly?")

InvalidRequestError: @declared_attr called outside of the declarative mapping process; is declarative_base() being used correctly?

[Mike Bayer]

OK, __tablename__ wasn't intended as a getter, typically you'd use __table__.name, because __tablename__ is not even guaranteed to be present. will see if there's some way to allow both cases here.

[Mike Bayer]

• Loosened some restrictions that were added to @declared_attr objects, such that they were prevented from being called outside of the declarative process; this is related to the enhancements of #3150 which allow @declared_attr to return a value that is cached based on the current class as it's being configured. The exception raise has been removed, and the behavior changed so that outside of the declarative process, the function decorated by @declared_attr is called every time just like a regular @property, without using any caching, as none is available at this stage. fixes #3331

→ <<cset cd076470baf2>>

[Mike Bayer]

ill put out beta2 soon and this will work again.