issue26981: add _order_ compatibility shim to enum.Enum

This commit is contained in:
Ethan Furman 2016-08-20 07:19:31 -07:00
parent 3e45875578
commit e8e61277ff
4 changed files with 100 additions and 3 deletions

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@ -257,7 +257,7 @@ members are not integers (but see `IntEnum`_ below)::
>>> Color.red < Color.blue
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
TypeError: unorderable types: Color() < Color()
TypeError: '<' not supported between instances of 'Color' and 'Color'
Equality comparisons are defined though::
@ -776,3 +776,22 @@ appropriately.
If you wish to change how :class:`Enum` members are looked up you should either
write a helper function or a :func:`classmethod` for the :class:`Enum`
subclass.
To help keep Python 2 / Python 3 code in sync a user-specified :attr:`_order_`,
if provided, will be checked to ensure the actual order of the enumeration
matches::
>>> class Color(Enum):
... _order_ = 'red green blue'
... red = 1
... blue = 3
... green = 2
...
Traceback (most recent call last):
...
TypeError: member order does not match _order_
.. note::
In Python 2 code the :attr:`_order_` attribute is necessary as definition
order is lost during class creation.

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@ -64,9 +64,11 @@ class _EnumDict(dict):
"""
if _is_sunder(key):
raise ValueError('_names_ are reserved for future Enum use')
if key not in ('_order_', ):
raise ValueError('_names_ are reserved for future Enum use')
elif _is_dunder(key):
pass
if key == '__order__':
key = '_order_'
elif key in self._member_names:
# descriptor overwriting an enum?
raise TypeError('Attempted to reuse key: %r' % key)
@ -106,6 +108,9 @@ class EnumMeta(type):
for name in classdict._member_names:
del classdict[name]
# adjust the sunders
_order_ = classdict.pop('_order_', None)
# check for illegal enum names (any others?)
invalid_names = set(members) & {'mro', }
if invalid_names:
@ -210,6 +215,14 @@ class EnumMeta(type):
if save_new:
enum_class.__new_member__ = __new__
enum_class.__new__ = Enum.__new__
# py3 support for definition order (helps keep py2/py3 code in sync)
if _order_ is not None:
if isinstance(_order_, str):
_order_ = _order_.replace(',', ' ').split()
if _order_ != enum_class._member_names_:
raise TypeError('member order does not match _order_')
return enum_class
def __bool__(self):

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@ -1571,6 +1571,68 @@ class TestEnum(unittest.TestCase):
self.assertEqual(LabelledList(1), LabelledList.unprocessed)
class TestOrder(unittest.TestCase):
def test_same_members(self):
class Color(Enum):
_order_ = 'red green blue'
red = 1
green = 2
blue = 3
def test_same_members_with_aliases(self):
class Color(Enum):
_order_ = 'red green blue'
red = 1
green = 2
blue = 3
verde = green
def test_same_members_wrong_order(self):
with self.assertRaisesRegex(TypeError, 'member order does not match _order_'):
class Color(Enum):
_order_ = 'red green blue'
red = 1
blue = 3
green = 2
def test_order_has_extra_members(self):
with self.assertRaisesRegex(TypeError, 'member order does not match _order_'):
class Color(Enum):
_order_ = 'red green blue purple'
red = 1
green = 2
blue = 3
def test_order_has_extra_members_with_aliases(self):
with self.assertRaisesRegex(TypeError, 'member order does not match _order_'):
class Color(Enum):
_order_ = 'red green blue purple'
red = 1
green = 2
blue = 3
verde = green
def test_enum_has_extra_members(self):
with self.assertRaisesRegex(TypeError, 'member order does not match _order_'):
class Color(Enum):
_order_ = 'red green blue'
red = 1
green = 2
blue = 3
purple = 4
def test_enum_has_extra_members_with_aliases(self):
with self.assertRaisesRegex(TypeError, 'member order does not match _order_'):
class Color(Enum):
_order_ = 'red green blue'
red = 1
green = 2
blue = 3
purple = 4
verde = green
class TestUnique(unittest.TestCase):
def test_unique_clean(self):

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@ -137,6 +137,9 @@ Library
- Issue #26800: Undocumented support of general bytes-like objects
as paths in os functions is now deprecated.
- Issue #26981: Add _order_ compatibility ship to enum.Enum for
Python 2/3 code bases.
- Issue #27661: Added tzinfo keyword argument to datetime.combine.
- In the curses module, raise an error if window.getstr() or window.instr() is