[Python-Dev] Could these restrictions be removed?

Antoine Pitrou solipsis at pitrou.net
Thu May 12 19:05:46 CEST 2011

On Thu, 12 May 2011 11:33:37 -0500 (CDT)
Skip Montanaro <skip at montanaro.dyndns.org> wrote:
> A friend at work who is new to Python wondered why this didn't work with
> pickle:
>     class Outer:
>         Class Inner:
>             ...
>         def __init__(self):
>             self.i = Outer.Inner()
> I've never questions this, but I wonder, is this a fundamental restriction
> or could it be overcome with a modest amount of work?

pickle uses heuristics to try to find out the "official name" of a
class or function. It would be a matter of improving these heuristics.

There are other cases in which pickle similarly fails:

>>> pickle.dumps(random.random)
>>> pickle.dumps(random.randint)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
_pickle.PicklingError: Can't pickle <class 'method'>: attribute lookup builtins.method failed



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