On Monday, July 8, 2013 12:45:55 AM UTC-7, Peter Otten wrote: > skunkwerk wrote: > > > > > Hi, > > > I'm using a custom pickler that replaces any un-pickleable objects (such > > > as sockets or files) with a string representation of them, based on the > > > code from Shane Hathaway here: > > > http://stackoverflow.com/questions/4080688/python-pickling-a-dict-with- > > some-unpicklable-items > > > > > > It works most of the time, but when I try to unpickle a Django > > > HttpResponse, I get the following error: UnpicklingError: NEWOBJ class > > > argument isn't a type object > > > > > > I have no clue what the error actually means. If it pickles okay, why > > > should it not be able to unpickle? Any ideas? > > > > A simple way to provoke the error is to rebind the name referring to the > > class of the pickled object: > > > > >>> import cPickle > > >>> class A(object): pass > > ... > > >>> p = cPickle.dumps(A(), -1) > > >>> cPickle.loads(p) > > <__main__.A object at 0x7fce7bb58c50> > > >>> A = 42 > > >>> cPickle.loads(p) > > Traceback (most recent call last): > > File "<stdin>", line 1, in <module> > > cPickle.UnpicklingError: NEWOBJ class argument isn't a type object > > > > You may be doing something to that effect.
Hey Peter, I tried unpickling even from another file with no other code in it, but came up with the same error - so I don't think it's a rebinding issue. But I got the error to disappear when I removed the "hasattr(obj, '__getstate__')" from this line of code in the persistent_id function: if not hasattr(obj, '__getstate__') and isinstance(obj,(basestring, bool, int, long, float, complex, tuple, list, set, dict)): return ["filtered:%s" % type(obj)] When I do that, I get a few more FilteredObjects in the result, for things like: <class 'django.core.handlers.wsgi.WSGIRequest'> <class 'MySQLdb.connections.Connection'> I figured these classes must have __getstate__ methods which leads to them being pickled without a persistent_id (it turns out they actually have __repr__ methods). So these classes get pickled fine, but run into problems when trying to unpickle them. I understand why ImportErrors would happen if the necessary modules haven't been loaded, but this NEWOBJ error is still kind of mystifying. I guess I just won't pickle any classes for now, if unpickling them is going to be dicey. thanks for the help guys, imran -- http://mail.python.org/mailman/listinfo/python-list