[Python-Dev] python2.7 infinite recursion when loading pickled object (original) (raw)

Akira Li 4kir4.1i at gmail.com
Mon Aug 11 15:01:31 CEST 2014

"Schmitt Uwe (ID SIS)" <uwe.schmitt at id.ethz.ch> writes:

I discovered a problem using cPickle.loads from CPython 2.7.6.

The last line in the following code raises an infinite recursion class T(object): def init(self): self.item = list() def getattr(self, name): return getattr(self.item, name) import cPickle t = T() l = cPickle.dumps(t) cPickle.loads(l) ... Is this a bug or did I miss something ?

The issue is that your getattr raises RuntimeError (due to infinite recursion) for non-existing attributes instead of AttributeError. To fix it, you could use object.getattribute:

class C: def init(self): self.item = [] def getattr(self, name): return getattr(object.getattribute(self, 'item'), name)

There were issues in the past due to {get,has}attr silencing non-AttributeError exceptions; therefore it is good that pickle breaks when it gets RuntimeError instead of AttributeError.

-- Akira

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