Exception RuntimeError: 'maximum recursion depth exceeded in __subclasscheck__' in <type 'exceptions.AttributeError'> ignored

[Former user]

This is the sqlalchemy object:

from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy import Column, String, PickleType

Base = declarative_base()

class Entity(Base):
    __tablename__ = 'entitys'
    name        = Column(String, primary_key=True, nullable = False)
    objType     = Column(String, nullable = False)
    objPickle   = Column(PickleType)

    def __init__(self, name, objType, objPickle):
        self.name = name
        self.objType=objType
        self.objPickle=objPickle

    def __repr__(self):
        return "<Entity('%s','%s')>" % (self.name,self.objType)

ObjPickle is something like

Class A(object):
    def __init__():
        self.objs={}

inside objs there is some objects that inerith from

class AdvancedIneritance(object):
    def __init__(self,objInerith):
        object.__setattr__(self,'objInerith',objInerith)

    def __getattr__(self,name):
        """
            overload of the getattr method
        """
        try:
            return getattr(self.objInerith,name)
        except:
            try:
                return getattr(self,name)
            except:
                raise AttributeError, name

if i use this tipe of inerithance i get the: Exception RuntimeError: 'maximum recursion depth exceeded in subclasscheck' in <type 'exceptions.AttributeError'> ignored

I made some debug, and I see the the recursion start in this function

def _execute_context(self, dialect, constructor, statement, parameters, *args): """Create an :class:.ExecutionContext and execute, returning a :class:.ResultProxy."""

    try:
        try:
            conn = self.__connection
        except AttributeError:
            conn = self._revalidate_connection()

        context = constructor(dialect, self, conn, *args) #<--- recursion 
    except Exception, e:
        self._handle_dbapi_exception(e, 
                    str(statement), parameters, 
                    None, None)
        raise

[Mike Bayer]

Sorry, from what I can see here this is just a problem local to the implementation of non-SQLalchemy classes:

class A(object):
    def __init__(self):
        self.objs={}

class AdvancedIneritance(object):
    def __init__(self,objInerith):
        object.__setattr__(self,'objInerith',objInerith)

    def __getattr__(self,name):
        """
            overload of the getattr method
        """
        try:
            return getattr(self.objInerith,name)
        except:
            try:
                print "GET!", name
                return getattr(self,name)
            except:
                raise AttributeError, name

a = A()
a.objs["foo"]("foo") = AdvancedIneritance("x")
import pickle

print pickle.loads(pickle.dumps(a))

The above simply hangs. This because of the of the recursion caused by __getattr__() leading to getattr() directly. I've added a "print" statement so that you can see it happening.

I had to assume this since the code examples posted here are only partial and I had to correct errors such as the missing "self" within __init__(). If you need to reopen this ticket, please attach a fully working test case and complete stack trace as per the guidelines at http://www.sqlalchemy.org/participate.html#bugs - thanks !