How can I replace the class by monkey patching?

Question

How can I replace the ORM class - so it should not cause recursion !!!

Problem:
original class has the super call, when its got replaced - it causes self inheritance and causes maximum recursion depth exceed exception.
i.e. class orm is calling super(orm, self).... and orm has been replaced by another class which inherits original orm....

Package !

addons  __init__.py  osv  run_app.py

./addons:
__init__.py  test_app1.py  test.py

./osv:
__init__.py  orm.py

contents of orm.py

class orm_template(object):
    def __init__(self, *args, **kw):
        super(orm_template, self).__init__()    
    def fields_get(self, fields):
        return fields    
    def browse(self, id):
        return id

class orm(orm_template):
    def __init__(self, *args, **kw):
        super(orm, self).__init__(*args, **kw)    
    def fields_get(self, fields, context = None):
        return super(orm, self).fields_get(fields)    
    def read(self, fields):
        return fields

contents of addons/init.py

import test    
def main(app):
    print "Running..."
    __import__(app, globals(), locals())

contents of addons/test.py

from osv import orm
import osv
class orm(orm.orm):
    def __init__(self, *args, **kw):
        super(orm, self).__init__(*args, **kw)    
    def fields_get(self, *args, **kw):
        print "my fields get................."
        return super(orm, self).fields_get(*args, **kw)    
osv.orm.orm = orm
print "replaced.........................."

contents of test_app1.py

from osv.orm import orm    
class hello(orm):
    _name = 'hellos'    
    def __init__(self, *args, **kw):
        super(hello, self).__init__(*args, **kw)    
print hello('test').fields_get(['name'])

contents of run_app.py

import addons
addons.main('test_app1')

OUTPUT

>>>python run_app.py

replaced..........................
Running...
...
...
super(orm, self).__init__(*args, **kw)
RuntimeError: maximum recursion depth exceeded

I've seen the similar question

Answer 1

Your addons/test.py needs to get and keep a reference to the original orm.orm and use that instead of the replaced version. I.e.:

from osv import orm
import osv
original_orm = osv.orm
class orm(original_orm):
    def __init__(self, *args, **kw):
        super(orm, self).__init__(*args, **kw)    
    def fields_get(self, *args, **kw):
        print "my fields get................."
        return super(orm, self).fields_get(*args, **kw)    
osv.orm.orm = orm
print "replaced.........................."

so the monkeypatched-in class inherit from the original rather than from itself, as you had it in your setup. BTW, if you can avoid monkey-patching by better design of the osv module (e.g. w/a setter function to set what's the orm) you'll be happier;-).