PyPy 1.5 bug where call to __getitem__ differs from CPython 2.7.1

test_pypy_cache.py

# This is a test case to describe a bug I'm seeing in PyPy 1.5. I have
# a Cache object that is a dictionary that supports lookup via regular
# attribute access. For instance:
#
#   >>> c = Cache()
#   >>> c["asdf"] = "asdf"
#   >>> c.asdf == c["asdf"]
#   True
#
# When looking up keys via attribute, PyPy 1.5 calls __getitem__
# whereas CPython 2.7.1 does not.

class Cache(dict):
    "A dictionary that supports attribute style key lookup"
    def __init__(self, **kw):
        dict.__init__(self, kw)
        self.__dict__ = self

class Test(Cache):
    def __getitem__(self, item):
        # I want to process items differently than attributes:
        raise Exception("Trying to getitem: %s" % item)

if __name__ == "__main__":
    t = Test()
    t["asdf"] = "asdf"
    #CPython does not call __getitem__ .. PyPy does:
    print t.asdf
    #Doesn't matter if it's a member of __dict__ or not:
    print t.__getattribute__