Comment 4 for bug 360761

The iterator support leads to problems for us - acquisition wrappers are lost during iteration. Here is an example that uses __iter__:

from Acquisition import Implicit

class B(Implicit):
    def __iter__(self):
        for i in range(5):
            yield i, self.aq_parent

class A(Implicit):
    pass

a = A()
a.b = B()

for (i, parent) in a.b:
    print i, parent

'self.aq_parent' fails here, as 'self' inside __iter__ isn't acquisition wrapped.

Worse is that *existing* code that has worked for years (namely ParsedXML) suddenly breaks, as it uses __getitem__ based iteration. The problem now is that this *always* uses iterators now, instead of using the old fallback. This means acquisition wrappers are lost within __getitem__ too now:

from Acquisition import Implicit

class B(Implicit):
    def __getitem__(self, i):
        if i == 5:
            raise IndexError()
        return i, self.aq_parent

class A(Implicit):
    pass

a = A()
a.b = B()

for (i, parent) in a.b:
    print i, parent

We do not know whether the implementation before this bugfix worked better with __iter__ but in any case we'd then again have the original reported issue that __getitem__ breaks.

We are seeing this issue appear in Zope 2.11.3, to which we're trying to port Silva, which relies on ParsedXML.