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Consider: >>> import pickle >>> thing = open('foobar.txt','w') >>> pickle.dumps(thing) Traceback (most recent call last): File "<stdin>", line 1, in <module> File "/usr/lib/python2.6/pickle.py", line 1366, in dumps Pickler(file, protocol).dump(obj) File "/usr/lib/python2.6/pickle.py", line 224, in dump self.save(obj) File "/usr/lib/python2.6/pickle.py", line 306, in save rv = reduce(self.proto) File "/usr/lib/python2.6/copy_reg.py", line 70, in _reduce_ex raise TypeError, "can't pickle %s objects" % base.__name__ TypeError: can't pickle file objects Seems entirely reasonable - of course I can't pickle an open file handle. But: >>> pickle.dumps(thing, 2) '\x80\x02c__builtin__\nfile\nq\x00)\x81q\x01.' >>> pickle.loads(pickle.dumps(thing, 2)) <closed file '<uninitialized file>', mode '<uninitialized file>' at 0x7ff3c078> Apparently I can pickle an open file, just not usefully. Is this deliberate? It was obscuring a bug in my code, where I was wrongly pickling an object that owned a file. Under some conditions, that object also holds a pyodbc cursor, with the same result. I don't see anything in PEP 307 about it. Was it just an oversight, or is there something important going on that I'm missing, that could let me get the exception I want even when pickling using protocol 2? I'm using Python 2.6.5. I know, I know, but it's what comes with my distribution.

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