auto-correlation regression regarding eager load, column prop, eg. the usual suspects

appeared some time in 0.7:
from sqlalchemy import *
from sqlalchemy.orm import *
from sqlalchemy.ext.declarative import declarative_base

Base = declarative_base()

class SnortEvent(Base):
    __tablename__ = "event"

    id = Column(Integer, primary_key=True)
    signature = Column(Integer, ForeignKey("signature.id"))

    signatures = relationship("Signature", lazy=False)

class Signature(Base):
    __tablename__ = "signature"

    id = Column(Integer, primary_key=True)

    sig_count = column_property(
                    select([func.count('*')](func.count('*'))).\
                        where(SnortEvent.signature == id)
                )

# workaround
#Signature.sig_count = column_property(
#                    select([func.count('*')](func.count('*'))).\
#                        where(SnortEvent.signature == Signature.id).\
#                        correlate(Signature.__table__)
#                )

session = Session()

print session.query(SnortEvent)



sqlalchemy.exc.InvalidRequestError: Select statement 'SELECT count(:param_1) AS count_1 
FROM event, signature AS signature_1 
WHERE event.signature = signature_1.id' returned no FROM clauses due to auto-correlation; specify correlate(<tables>) to control correlation manually.
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