closes issue18042 -- a `unique` decorator is added to enum.py
The docs also clarify the 'Interesting Example' duplicate-free enum is for
demonstration purposes.
diff --git a/Lib/enum.py b/Lib/enum.py
index 775489b..38d95c5 100644
--- a/Lib/enum.py
+++ b/Lib/enum.py
@@ -4,7 +4,7 @@
from collections import OrderedDict
from types import MappingProxyType
-__all__ = ['Enum', 'IntEnum']
+__all__ = ['Enum', 'IntEnum', 'unique']
class _RouteClassAttributeToGetattr:
@@ -463,3 +463,17 @@
class IntEnum(int, Enum):
"""Enum where members are also (and must be) ints"""
+
+
+def unique(enumeration):
+ """Class decorator for enumerations ensuring unique member values."""
+ duplicates = []
+ for name, member in enumeration.__members__.items():
+ if name != member.name:
+ duplicates.append((name, member.name))
+ if duplicates:
+ alias_details = ', '.join(
+ ["%s -> %s" % (alias, name) for (alias, name) in duplicates])
+ raise ValueError('duplicate values found in %r: %s' %
+ (enumeration, alias_details))
+ return enumeration
diff --git a/Lib/test/test_enum.py b/Lib/test/test_enum.py
index 75b2656..2b87c56 100644
--- a/Lib/test/test_enum.py
+++ b/Lib/test/test_enum.py
@@ -2,7 +2,7 @@
import unittest
from collections import OrderedDict
from pickle import dumps, loads, PicklingError
-from enum import Enum, IntEnum
+from enum import Enum, IntEnum, unique
# for pickle tests
try:
@@ -917,5 +917,38 @@
self.assertEqual(Planet.EARTH.value, (5.976e+24, 6.37814e6))
+class TestUnique(unittest.TestCase):
+
+ def test_unique_clean(self):
+ @unique
+ class Clean(Enum):
+ one = 1
+ two = 'dos'
+ tres = 4.0
+ @unique
+ class Cleaner(IntEnum):
+ single = 1
+ double = 2
+ triple = 3
+
+ def test_unique_dirty(self):
+ with self.assertRaisesRegex(ValueError, 'tres.*one'):
+ @unique
+ class Dirty(Enum):
+ one = 1
+ two = 'dos'
+ tres = 1
+ with self.assertRaisesRegex(
+ ValueError,
+ 'double.*single.*turkey.*triple',
+ ):
+ @unique
+ class Dirtier(IntEnum):
+ single = 1
+ double = 1
+ triple = 3
+ turkey = 3
+
+
if __name__ == '__main__':
unittest.main()