[Sqlalchemy-tickets] Issue #3388: instrument_class event is being called at the wrong time in 1.0 (zzzeek/sqlalchemy)

[Mike B. <iss...@bi...>]

New issue 3388: instrument_class event is being called at the wrong time in 1.0
https://bitbucket.org/zzzeek/sqlalchemy/issue/3388/instrument_class-event-is-being-called-at

Mike Bayer:

this works in 0.9, fails in 1.0.  Not really sure how this can be happening since nothing should have changed in this regard:


```
#!python

from sqlalchemy import event
from sqlalchemy import MetaData, Table, Column, Integer
from sqlalchemy.orm import mapper


def my_init(self):
    print("hi")


@event.listens_for(mapper, "instrument_class")
def instrument_class(mp, class_):
    print("INSTRUMENT CLASS!")
    class_.__init__ = my_init

m = MetaData()
foo = Table('foo', m, Column('id', Integer, primary_key=True))


class Foo(object):
    pass

```

mapper(Foo, foo)

f1 = Foo()
assert f1._sa_instance_state