Issue1991

This might be limited to the itertools library, as I was not able to reproduce this using freeform iterator objects...nonetheless this is pretty core.

Propagation of iterator objects, at least in the case of itertools.chain(), appears to be broken:

from itertools import chain

class MyClass(object):
    def __iter__(self):
        return chain([1, 2, 3])


my_obj = MyClass()

print list(my_obj)  # python prints [1,2,3], jython prints []

chain_obj = my_obj.__iter__()

assert list(chain_obj) == list(my_obj)


Above, the "chain()" object returned by my_obj.__iter__() works fine and yields [1,2,3], however when my_obj itself is called in an iterator context, the iterator yields nothing.  The assertion at the end fails on Jython and passes on cPython.

zzzeek: thanks for the ongoing beat down on 2.7 - I'll keep an eye on these!