polymorphic aliasing failure when using trivial column subclass

[Mike Bayer]

this seems like an 0.9 regression

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)

class MySpecialColumn(Column):
    pass


class B(A):
    __tablename__ = 'b'

    id = Column(ForeignKey('a.id'), primary_key=True)
    x = MySpecialColumn(String)

s = Session()

print s.query(A).join(B).filter(B.x == 'asdf')

[Mike Bayer]

it's annotations, here's a test case:

from sqlalchemy import Column

class MySpecialColumn(Column):
    pass


col = MySpecialColumn('x', String)
binary_1 = col == 5   # caches col.comparator, col.comparator.expr == col
c2 = col._annotate({"x": "foo"})   # uses Annotated, not AnnotatedColumn, as base class
binary_2 = c2 == 5   # fails to use a new col.comparator, uses the old one with col and missing annotations
assert binary_2.left._annotations == {"x": "foo"}

[Mike Bayer]

15b23c7f71c0ca8c526db2794b2c459c848, also the tests have been backported to 0.8 in 2866577231511a9d38ab9c7c42ce68b.