[issue16231] pickle persistent_id return value

[PSchaafsma]

New submission from PSchaafsma:

The documentation of persistent_id prescribes that returning None will cause default pickling behavior. This makes sense.

However, in the Pickler.save function in pickle.py, the return value of persistent_id checked as boolean, causing also return values like 0 and [] to indicate default pickling.

This becomes a problem when unpickleable objects are identified by a simple index in some other list.

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components: Library (Lib)
messages: 172887
nosy: pschaafsma
priority: normal
severity: normal
status: open
title: pickle persistent_id return value
type: behavior
versions: Python 2.7

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Python tracker <report at bugs.python.org>
<http://bugs.python.org/issue16231>
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