[Sqlalchemy-tickets] Issue #3626: @validates is not called on inherited subclasses (zzzeek/sqlalchemy)

[diego p. <iss...@bi...>]

New issue 3626: @validates is not called on inherited subclasses
https://bitbucket.org/zzzeek/sqlalchemy/issues/3626/validates-is-not-called-on-inherited

diego pego:

I think this is related to but do not duplicates #2943


```
#!python

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)
    data = Column(String)
    reg_type = Column(String)

    @validates('data')
    def validate(self, key, value):
        return "yup A " + value

    __mapper_args__ = {
        'polymorphic_identity':'a',
        'polymorphic_on':reg_type
    }


class B(A):
    __tablename__ = 'b'
    other_data = Column(String)

    @validates('other_data ')
    def validate_other_data(self, key, value):
        # >>>>> this is never called
        assert value.strip() != ''
        return value

    __mapper_args__ = {
        'polymorphic_identity':'TYPE_B',
    }
```