[Python-Dev] __eq__ vs hash

[Ralf Schmitt]

On Fri, Apr 4, 2008 at 4:38 PM, Guido van Rossum <guido at python.org> wrote:

> On Fri, Apr 4, 2008 at 2:46 AM, Ralf Schmitt <schmir at gmail.com> wrote:
> > the news file for python 2.6 does not mention that you need to define
> > __hash__ in case you define __eq__ for a class.
> > This breaks some code (for me: mercurial and pyparsing).
> > Shouldn't this be documented somewhere (I also cannot find it in the
> > whatsnew file).
>
> Well, technically this has always been the requirement.
>

> What specific code breaks? Maybe we need to turn this into a warning
> in order to be more backwards compatible?
>

I don't feel like digging into mercurial or pyparsing code currently. sorry.
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