[Python-Dev] python 3.0, tp_compare not used for == test?

["Martin v. Löwis"]

> I'm wondering if Mark should add the exception he recently removed back
> in as a Deprecation Warning when tp_compare is defined, but
> tp_richcompare is not. Such a warning should also be present when
> running with -3 in 2.7 (assuming it isn't already there).
> 
> Otherwise we're going to get more questions like Campbell's wondering if
> it is intentional that tp_compare is no longer getting called in the 3.x
> series (the warnings would both make it explicit and give guidance on
> what to do about it).

Mark removed the cmpfunc typedef; that should cause compilation in many
extension modules (except those which don't actually cast to cmpfunc,
but get the type right in the first place).

Also, if you then investigate why it doesn't get called, you'll notice
quickly that the slot doesn't even have the right name anymore. So
Campbell's surprise would be gone - he wouldn't have been able to still
invoke tp_compare through the cmp() builtin.

Regards,
Martin