Bug: http://bugs.python.org/issue28437
On Thu, Oct 13, 2016 at 7:15 PM Neil Girdhar <mistersh...@gmail.com> wrote: > That's fair. However, the documentation should at least be repaired by > replacing section 3.3.3.2 with: > > "The metaclass of a class definition is selected from the explicitly > specified metaclass (if any) and the metaclasses (i.e. type(cls)) of all > specified base classes. The most derived metaclass is one which is a > subtype of all of these candidate metaclasses. If none of the candidate > metaclasses meets that criterion, then the class definition will fail with > TypeError. If provided, the explicit metaclass must be a callable accepting > the positional arguments (name, bases, _dict)." > > This is because something happened along the way and Objects/typeobject.c: > type_new no longer coincides with Lib/types.py:new_class. The Python > version conditionally calls _calculate_meta whereas the C version calls it > unconditionally. I consider the C implementation to be the "correct" > version. > > Best, > > Neil > > On Thu, Oct 13, 2016 at 5:41 PM Steven D'Aprano <st...@pearwood.info> > wrote: > > On Thu, Oct 13, 2016 at 01:46:34PM -0700, Neil Girdhar wrote: > > > If provided, the explicit metaclass must be an instance of > > type()." > > -1 for pointless breakage. > > The metaclass has always been permitted to be any callable. You haven't > given any good reason for gratuitously changing this. > > > > -- > Steve > _______________________________________________ > Python-ideas mailing list > Python-ideas@python.org > https://mail.python.org/mailman/listinfo/python-ideas > Code of Conduct: http://python.org/psf/codeofconduct/ > > -- > > --- > You received this message because you are subscribed to a topic in the > Google Groups "python-ideas" group. > To unsubscribe from this topic, visit > https://groups.google.com/d/topic/python-ideas/wrHDM0SOIqE/unsubscribe. > To unsubscribe from this group and all its topics, send an email to > python-ideas+unsubscr...@googlegroups.com. > For more options, visit https://groups.google.com/d/optout. > >
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