This issue tracker has been migrated to GitHub, and is currently read-only.
For more information, see the GitHub FAQs in the Python's Developer Guide.

Author ncoghlan
Recipients ncoghlan
Date 2013-05-23.08:56:17
SpamBayes Score -1.0
Marked as misclassified Yes
Message-id <>
Another attempt at tackling the "but I want to ensure my enum values are unique" problem that PEP 435 deliberately chose not to handle. My previous suggestion (in issue 17959) was rightly rejected due to the other problems it caused, but this idea is much cleaner and simpler.

All we would need to do is provide the following class decorator in the enum module:

    def unique(new_enum):
        for name, member in new_enum.__members__.items():
            if name !=
                msg = "Alias {!r} for {!r} not permitted in unique Enum"
                raise TypeError(msg.format(name, member))
        return new_enum

Used as so:

>>> @enum.unique
... class MyEnum(enum.Enum):
...     a = 1
...     b = 2
...     c = 1
Traceback (most recent call last):
  File "<stdin>", line 2, in <module>
  File "<stdin>", line 6, in unique
TypeError: Alias 'c' for <MyEnum.a: 1> not permitted in unique Enum
Date User Action Args
2013-05-23 08:56:18ncoghlansetrecipients: + ncoghlan
2013-05-23 08:56:18ncoghlansetmessageid: <>
2013-05-23 08:56:18ncoghlanlinkissue18042 messages
2013-05-23 08:56:17ncoghlancreate