[Zope-Coders] new.instancemethod behavior under py22 vs. py21

[Chris McDonough]

Here's a bit of code that acts differently under Python 2.2 vs. Python
2.1:

from ExtensionClass import Base
from Acquisition import ImplicitAcquisitionWrapper
import new

class anextensionclass(Base):
    pass

def afunction(self):
    return 1

a = anextensionclass()
b = anextensionclass()
c = ImplicitAcquisitionWrapper(a, b)

print new.instancemethod(afunction, c, c.__class__)

Under Python 2.1.3, this code barfs with:

Traceback (most recent call last):
  File "rebindtest.py", line 15, in ?
    print new.instancemethod(afunction, c, c.__class__)
TypeError: instancemethod() argument 3 must be class, not ExtensionClass

While under Python 2.2.2, it prints:

<bound method anextensionclass.afunction of <anextensionclass instance
at 8161678>>

I suspect the difference has something to do with type/class unification
or perhaps some special casing put into Python 2.2 wrt ExtensionClass
objects.

In any case, given that this doesn't work under Python 2.1, can anyone
shed some light on dynamically rebinding functions to extensionclass
instances as methods under Python 2.1?

- C