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Re: Hash stability

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To python-list@python.org
From Terry Reedy <tjreedy@udel.edu>
Subject Re: Hash stability
Date Sat, 14 Jan 2012 23:07:13 -0500
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On 1/14/2012 9:26 PM, Roy Smith wrote:
>   Steven D'Aprano<steve+comp.lang.python@pearwood.info>  wrote:
>> How many people rely on hash(some_string) being stable across Python
>> versions? Does anyone have code that will be broken if the string hashing
>> algorithm changes?
>
> I would never rely on something like that unless the docs unambiguously
> stated it were so.  Which they don't.  All I can find about hash() is:
>
> "Return the hash value of the object (if it has one).

Based on the pydev discussion since, it appears that enough people have 
inferred stability either from that or empirical stability that it will 
not be broken, by default, in pre-3.3 releases. What ever option is 
chosen to guard against attacks will probably be the default in 3.3.

-- 
Terry Jan Reedy

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Thread

Hash stability Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-01-14 04:42 +0000
  Re: Hash stability Peter Otten <__peter__@web.de> - 2012-01-14 10:46 +0100
  Re: Hash stability Heiko Wundram <modelnine@modelnine.org> - 2012-01-14 23:45 +0100
  Re: Hash stability Chris Angelico <rosuav@gmail.com> - 2012-01-15 11:36 +1100
    Re: Hash stability Bryan <bryanjugglercryptographer@yahoo.com> - 2012-01-15 04:03 -0800
      Re: Hash stability Chris Angelico <rosuav@gmail.com> - 2012-01-15 23:21 +1100
  Re: Hash stability Roy Smith <roy@panix.com> - 2012-01-14 21:26 -0500
    Re: Hash stability Terry Reedy <tjreedy@udel.edu> - 2012-01-14 23:07 -0500
  Re: Hash stability Stefan Behnel <stefan_ml@behnel.de> - 2012-01-15 11:13 +0100
  Re: Hash stability Heiko Wundram <modelnine@modelnine.org> - 2012-01-15 12:46 +0100
  Re: Hash stability Peter Otten <__peter__@web.de> - 2012-01-15 13:22 +0100
  Re: Hash stability Heiko Wundram <modelnine@modelnine.org> - 2012-01-15 17:07 +0100
  Re: Hash stability Chris Angelico <rosuav@gmail.com> - 2012-01-16 03:13 +1100
  Re: Hash stability Heiko Wundram <modelnine@modelnine.org> - 2012-01-15 17:51 +0100
  Re: Hash stability Stefan Behnel <stefan_ml@behnel.de> - 2012-01-15 18:20 +0100
  Re: Hash stability Peter Otten <__peter__@web.de> - 2012-01-16 09:18 +0100
  Re: Hash stability Christian Heimes <lists@cheimes.de> - 2012-01-16 09:44 +0100
  Re: Hash stability Heiko Wundram <modelnine@modelnine.org> - 2012-01-16 10:15 +0100

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