[issue33862] doc Fix Enum __members__ type
New submission from Andrés Delfino <adelfino@gmail.com>: Documentation says __members__ attribute returns an "ordered dictionary" but it returns a mappingproxy instead. PR fixes this. ---------- assignee: docs@python components: Documentation messages: 319532 nosy: adelfino, docs@python priority: normal severity: normal status: open title: doc Fix Enum __members__ type type: enhancement versions: Python 3.6, Python 3.7, Python 3.8 _______________________________________ Python tracker <report@bugs.python.org> <https://bugs.python.org/issue33862> _______________________________________
Change by Andrés Delfino <adelfino@gmail.com>: ---------- keywords: +patch pull_requests: +7309 stage: -> patch review _______________________________________ Python tracker <report@bugs.python.org> <https://bugs.python.org/issue33862> _______________________________________
Serhiy Storchaka <storchaka+cpython@gmail.com> added the comment: Is not returning a mappingproxy an implementation detail? The important thing is that the result is a mapping of names to members, and that it is ordered. ---------- nosy: +barry, eli.bendersky, ethan.furman, serhiy.storchaka _______________________________________ Python tracker <report@bugs.python.org> <https://bugs.python.org/issue33862> _______________________________________
Andrés Delfino <adelfino@gmail.com> added the comment: I can't really say if it the return of __members__ is an implementation detail as there's no mention of that in the doc, but from reading the doc I think it's reasonable to think this is allowed: import enum class Colors(enum.Enum): RED = enum.auto() BLUE = enum.auto() Colors.__members__['GREEN'] = enum.auto() And the traceback: Traceback (most recent call last): File "<pyshell#8>", line 1, in <module> Colors.__members__['GREEN'] = enum.auto() TypeError: 'mappingproxy' object does not support item assignment is somewhat confusing, as the documentation says an "ordered dictionary" is to be returned, and the traceback talks about a mapping proxy. ---------- _______________________________________ Python tracker <report@bugs.python.org> <https://bugs.python.org/issue33862> _______________________________________
Ethan Furman <ethan@stoneleaf.us> added the comment: Serhiy is correct. The exact return type only needs to be ordered, and have appropriate dictionary methods such as `keys()`, `values()`, and `items()`. The reason a mappingproxy was chosen is exactly because what you just tried is illegal and/or confusing: - illegal because an Enum cannot be modified that way - confusing because the dictionary returned is only a copy of the Enum class' __dict__, and successful attempts to modify it would not change the Enum class. It is an implementation detail because the exact type of dictionary returned could change in the future. ---------- assignee: docs@python -> ethan.furman resolution: -> not a bug stage: patch review -> resolved status: open -> closed _______________________________________ Python tracker <report@bugs.python.org> <https://bugs.python.org/issue33862> _______________________________________
participants (3)
-
Andrés Delfino -
Ethan Furman
-
Serhiy Storchaka