[Python-bugs-list] [ python-Feature Requests-558238 ] Pickling bound methods
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Tue, 24 Sep 2002 11:12:09 -0700
Feature Requests item #558238, was opened at 2002-05-20 13:17
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Category: Python Library
Group: None
Status: Open
Resolution: None
Priority: 5
Submitted By: Konrad Hinsen (hinsen)
>Assigned to: Martin v. Löwis (loewis)
Summary: Pickling bound methods
Initial Comment:
Last week I noticed that the pickle and cPickle modules
cannot handle bound methods. I found a solution that is
simple and (I think) general, so perhaps it should
become part of the standard library.
Here is my code:
import copy_reg
def pickle_bound_method(method):
return getattr, (method.im_self, method.__name__)
class _Foo:
def bar(self):
pass
_foo = _Foo()
copy_reg.constructor(getattr)
copy_reg.pickle(type(_foo.bar), pickle_bound_method)
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>Comment By: Martin v. Löwis (loewis)
Date: 2002-09-24 20:12
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That sounds good to me; I'm going to install it.
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Comment By: Konrad Hinsen (hinsen)
Date: 2002-09-24 19:54
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Of course:
import copy_reg
def get_method(object, name):
klass = object.__class__
fn = klass.__dict__[name]
return new.instancemethod(fn, object, klass)
def pickle_bound_method(method):
return get_method, (method.im_self, method.__name__)
class _Foo:
def bar(self):
pass
_foo = _Foo()
copy_reg.constructor(get_method)
copy_reg.pickle(type(_foo.bar), pickle_bound_method)
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Comment By: Martin v. Löwis (loewis)
Date: 2002-09-22 15:08
Message:
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Can you perhaps rewrite this to use new.instancemethod?
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Comment By: Martin v. Löwis (loewis)
Date: 2002-06-09 19:14
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Making getattr a safe_constructor has security implictions
which make this approach dangerous. It seems that unpickling
might invoke arbitrary __getattr__ implementations. Adding a
protocol to declare classes as "safe for getattr" might help.
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