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bpo-44524: Do not set _name of _SpecialForm without need #27861

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Merged
merged 1 commit into from
Aug 21, 2021
Merged

bpo-44524: Do not set _name of _SpecialForm without need #27861

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1 change: 0 additions & 1 deletion Lib/test/test_typing.py
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Original file line number Diff line number Diff line change
Expand Up @@ -4929,7 +4929,6 @@ def test_special_attrs(self):
self.assertEqual(cls.__name__, name, str(cls))
self.assertEqual(cls.__qualname__, name, str(cls))
self.assertEqual(cls.__module__, 'typing', str(cls))
self.assertEqual(getattr(cls, '_name', name), name, str(cls))
for proto in range(pickle.HIGHEST_PROTOCOL + 1):
s = pickle.dumps(cls, proto)
loaded = pickle.loads(s)
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19 changes: 8 additions & 11 deletions Lib/typing.py
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Original file line number Diff line number Diff line change
Expand Up @@ -461,7 +461,7 @@ class Starship:
be used with isinstance() or issubclass().
"""
item = _type_check(parameters, f'{self} accepts only single type.')
return _GenericAlias(self, (item,), name="ClassVar")
return _GenericAlias(self, (item,))

@_SpecialForm
def Final(self, parameters):
Expand All @@ -482,7 +482,7 @@ class FastConnector(Connection):
There is no runtime checking of these properties.
"""
item = _type_check(parameters, f'{self} accepts only single type.')
return _GenericAlias(self, (item,), name="Final")
return _GenericAlias(self, (item,))

@_SpecialForm
def Union(self, parameters):
Expand Down Expand Up @@ -520,12 +520,9 @@ def Union(self, parameters):
parameters = _remove_dups_flatten(parameters)
if len(parameters) == 1:
return parameters[0]

if len(parameters) == 2 and type(None) in parameters:
name = "Optional"
else:
name = "Union"
return _UnionGenericAlias(self, parameters, name=name)
return _UnionGenericAlias(self, parameters, name="Optional")
return _UnionGenericAlias(self, parameters)
Comment on lines +524 to +525
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@Fidget-Spinner Fidget-Spinner Aug 21, 2021 •
edited
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Will there be a subtle difference between how the two behaves since one sets name and the other doesn't?

I would think not but I'm not sure.

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Setting _name affects subclassing and pickling/copying. Union[] and Optional[] are not subclassable, and special implementation of __reduce__ was added in previous commits. If there are other difference, I do not know.


@_SpecialForm
def Optional(self, parameters):
Expand Down Expand Up @@ -570,7 +567,7 @@ def open_helper(file: str, mode: MODE) -> str:
except TypeError: # unhashable parameters
pass

return _LiteralGenericAlias(self, parameters, name="Literal")
return _LiteralGenericAlias(self, parameters)


@_SpecialForm
Expand Down Expand Up @@ -609,7 +606,7 @@ def Concatenate(self, parameters):
"ParamSpec variable.")
msg = "Concatenate[arg, ...]: each arg must be a type."
parameters = tuple(_type_check(p, msg) for p in parameters)
return _ConcatenateGenericAlias(self, parameters, name="Concatenate")
return _ConcatenateGenericAlias(self, parameters)


@_SpecialForm
Expand Down Expand Up @@ -657,7 +654,7 @@ def is_str(val: Union[str, float]):
PEP 647 (User-Defined Type Guards).
"""
item = _type_check(parameters, f'{self} accepts only single type.')
return _GenericAlias(self, (item,), name="TypeGuard")
return _GenericAlias(self, (item,))


class ForwardRef(_Final, _root=True):
Expand Down Expand Up @@ -962,7 +959,7 @@ def __mro_entries__(self, bases):

def __getattr__(self, attr):
if attr in {'__name__', '__qualname__'}:
return self._name
return self._name or self.__origin__.__name__
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This solution is so nice. I wish I'd thought about this a little deeper when I proposed the original one:(.

Anyways if I'm not wrong, __origin__ will always be set on all GenericAlias to some type, so this should always succeed.


# We are careful for copy and pickle.
# Also for simplicity we just don't relay all dunder names
Expand Down