Author pitrou
Recipients Arach, Arfrever, Huzaifa.Sidhpurwala, Jim.Jewett, Mark.Shannon, PaulMcMillan, Zhiping.Deng, alex, barry, benjamin.peterson, christian.heimes, dmalcolm, eric.snow, fx5, georg.brandl, grahamd, gregory.p.smith, gvanrossum, gz, haypo, jcea, lemburg, mark.dickinson, merwok, neologix, pitrou, skrah, terry.reedy, tim.peters, v+python, zbysz
Date 2012-01-25.19:28:08
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Le mercredi 25 janvier 2012 à 19:19 +0000, Dave Malcolm a écrit :
> Dave Malcolm <dmalcolm@redhat.com> added the comment:
> 
> On Wed, 2012-01-25 at 18:05 +0000, Antoine Pitrou wrote:
> > Antoine Pitrou <pitrou@free.fr> added the comment:
> > 
> > > I'm attaching a revised version of the patch that should fix the above
> > > issue:
> > >   hybrid-approach-dmalcolm-2012-01-25-002.patch
> > 
> > It looks like that approach will break any non-builtin type (in either C
> > or Python) which can compare equal to bytes or str objects. If that's
> > the case, then I think the likelihood of acceptance is close to zero.
> 
> How?

This kind of type, for example:

class C:
    def __hash__(self):
        return hash(self._real_str)

    def __eq__(self, other):
        if isinstance(other, C):
           other = other._real_str
        return self._real_str == other

If I'm not mistaken, looking up C("abc") will stop matching "abc" when
there are too many collisions in one of your dicts.

> > Also, the level of complication is far higher than in any other of the
> > proposed approaches so far (I mean those with patches), which isn't
> > really a good thing.
> 
> So would I.  I want something I can backport, though.

Well, your approach sounds like it subtly and unpredictably changes the
behaviour of dicts when there are too many collisions, so I'm not sure
it's a good idea to backport it, either.

If we don't want to backport full hash randomization, I think I much
prefer raising a BaseException when there are too many collisions,
rather than this kind of (excessively) sophisticated workaround. You
*are* changing a fundamental datatype in a rather complicated way.
History
Date User Action Args
2012-01-25 19:28:10pitrousetrecipients: + pitrou, lemburg, gvanrossum, tim.peters, barry, georg.brandl, terry.reedy, gregory.p.smith, jcea, mark.dickinson, haypo, christian.heimes, benjamin.peterson, merwok, grahamd, Arfrever, v+python, alex, zbysz, skrah, dmalcolm, gz, neologix, Arach, Mark.Shannon, eric.snow, Zhiping.Deng, Huzaifa.Sidhpurwala, Jim.Jewett, PaulMcMillan, fx5
2012-01-25 19:28:09pitroulinkissue13703 messages
2012-01-25 19:28:08pitroucreate