diff options
Diffstat (limited to 'Lib/enum.py')
| -rw-r--r-- | Lib/enum.py | 32 |
1 files changed, 30 insertions, 2 deletions
diff --git a/Lib/enum.py b/Lib/enum.py index f6c7e8b..83e050e 100644 --- a/Lib/enum.py +++ b/Lib/enum.py @@ -9,6 +9,14 @@ __all__ = [ ] +class _NoInitSubclass: + """ + temporary base class to suppress calling __init_subclass__ + """ + @classmethod + def __init_subclass__(cls, **kwds): + pass + def _is_descriptor(obj): """ Returns True if obj is a descriptor, False otherwise. @@ -157,7 +165,7 @@ class EnumMeta(type): ) return enum_dict - def __new__(metacls, cls, bases, classdict): + def __new__(metacls, cls, bases, classdict, **kwds): # an Enum class is final once enumeration items have been defined; it # cannot be mixed with other types (int, float, etc.) if it has an # inherited __new__ unless a new __new__ is defined (or the resulting @@ -192,8 +200,22 @@ class EnumMeta(type): if '__doc__' not in classdict: classdict['__doc__'] = 'An enumeration.' + # postpone calling __init_subclass__ + if '__init_subclass__' in classdict and classdict['__init_subclass__'] is None: + raise TypeError('%s.__init_subclass__ cannot be None') + # remove current __init_subclass__ so previous one can be found with getattr + new_init_subclass = classdict.pop('__init_subclass__', None) # create our new Enum type - enum_class = super().__new__(metacls, cls, bases, classdict) + if bases: + bases = (_NoInitSubclass, ) + bases + enum_class = type.__new__(metacls, cls, bases, classdict) + enum_class.__bases__ = enum_class.__bases__[1:] #or (object, ) + else: + enum_class = type.__new__(metacls, cls, bases, classdict) + old_init_subclass = getattr(enum_class, '__init_subclass__', None) + # and restore the new one (if there was one) + if new_init_subclass is not None: + enum_class.__init_subclass__ = classmethod(new_init_subclass) enum_class._member_names_ = [] # names in definition order enum_class._member_map_ = {} # name->value map enum_class._member_type_ = member_type @@ -305,6 +327,9 @@ class EnumMeta(type): if _order_ != enum_class._member_names_: raise TypeError('member order does not match _order_') + # finally, call parents' __init_subclass__ + if Enum is not None and old_init_subclass is not None: + old_init_subclass(**kwds) return enum_class def __bool__(self): @@ -682,6 +707,9 @@ class Enum(metaclass=EnumMeta): else: return start + def __init_subclass__(cls, **kwds): + super().__init_subclass__(**kwds) + @classmethod def _missing_(cls, value): return None |