[Python-Dev] PEP 520: Preserving Class Attribute Definition Order (round 5)

Random832 random832 at fastmail.com
Fri Jun 24 19:56:04 EDT 2016

On Fri, Jun 24, 2016, at 17:52, Eric Snow wrote:
> - 2 open questions (__slots__?  drop read-only requirement?)

It's worth noting that __slots__ itself doesn't have a read-only
requirement. It can be a tuple, any iterable of strings, or a single
string (which means the object has a single slot).

Should dir() iterate in the order of __definition_order__? What, if so,
should be done about instance attributes, or attributes of multiple
classes, or class attributes not present in __definition_order__?

What happens to classes whose __prepare__ doesn't return an OrderedDict?

Can __definition_order__ be reassigned at runtime? Will it have the same

What if a metaclass defines __getattribute__ in a way that specially
handles __definition_order__? If someone really wants to put a non-tuple
there they will find a way. How hard do we want to think about ways to
stop consenting adults from doing weird things with the
__definition_order__ attribute?

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