Wrapper_iter does not clear error on success

[Federico G. Schwindt]

_Acquisition.c's Wrapper_iter() doesn't call PyErr_Clear() if PyObject_GetAttr() failed but PySequence_Check() succeeded.
This causes mysterious "AttributeError: __iter__" on otherwise valid code.

The following example shows the issue:

from Acquisition import Implicit
class C(Implicit):
    l = [0, 1, 2, 3, 4]
    def __getitem__(self, i):
        return self.l[i]
a = C()
b = C().__of__(a)
import time
try:
    for n in b:
        time.gmtime()
except AttributeError:
    raise

To fix it simply add the missing PyErr_Clear() after if (PySequence_Check(obj)).

[Tres Seaver (tseaver)]

Thanks for the report. Test and fix pushed for the 4.0.1 release of Acquisition:

  https://github.com/zopefoundation/Acquisition/commit/7b5c5fd19d6672df4573137487da818c45827b0f

[Tres Seaver (tseaver)]

https://pypi.python.org/pypi/Acquisition/4.0.1#changelog