[New-bugs-announce] [issue16373] Recursion error comparing set() and MutableMapping.keys()

[Nick Coghlan]

New submission from Nick Coghlan:

Try these in 3.3 (or Python 3.2 for the latter):

    set() < collections.ChainMap().keys()
    set() < collections.UserDict().keys()

Both fail with max recursion depth exceeded.

Given that both exhibit this behaviour, the core of the problem is quite possibly in MutableMapping.

(Uncovered while attempting to find a tidier ChainMap-based way to implement __subclasshook__ checks for ducktyping based on multiple methods)

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messages: 174286
nosy: ncoghlan
priority: normal
severity: normal
status: open
title: Recursion error comparing set() and MutableMapping.keys()
versions: Python 3.2, Python 3.3, Python 3.4

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Python tracker <report at bugs.python.org>
<http://bugs.python.org/issue16373>
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