Hi Seo,

Seems the problem is that Method does not have a __get__ (since C.m returns a Method not a Function via __get__ while assigning to D). In other words

mm = C.m
D.m = mm
assert D.m == mm     # True since no __get__()
assert C.m != mm     # True since __get__() creates a new method

Some simple fixes are

1. add a __get__() method to interpreter.function.Method which forwards request onto w_function attribute.

2. put a hack in objspace/descrooperation.DescrOperation in get() to handle special case for Method (yuk!)


The CPython implementation seems to be doing some hairy caching instead of creating new method each __get__(), so it hard to tell if this is correct behaviour. And the above fixes are only based on my understanding of desciptors, which has a high probability to be wrong. If someone backs me up I can commit fix 1. :-)


Cheers,
Richard


On Sat, 3 Jul 2004, Seo Sanghyeon wrote:

Consider following testcase:

class C: pass
class D(C): pass
def m(self): return self
C.m = m
D.m = C.m
print C().m()
print D().m()

CPython runs it okay, but PyPy baffles and raises TypeError, with
message ${SUBJ}.

Changing 5th line to "D.m = m" and it runs fine. The point is,
"D.m = C.m" should transform C.m from unbound method of class C to
unbound method of class D...

This breaks mailbox.py, among other things. Read how
PortableUnixMailbox is implemented there.

Regards,
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