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gh-74690: Don't set special protocol attributes on non-protocol subclasses of protocols #104622

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Merged
merged 1 commit into from
May 18, 2023
Merged

gh-74690: Don't set special protocol attributes on non-protocol subclasses of protocols #104622

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15 changes: 15 additions & 0 deletions Lib/test/test_typing.py
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Original file line number Diff line number Diff line change
Expand Up @@ -3167,6 +3167,21 @@ def meth(self): pass
self.assertIsInstance(NonPR(), PR)
self.assertIsSubclass(NonPR, PR)

self.assertNotIn("__protocol_attrs__", vars(NonP))
self.assertNotIn("__protocol_attrs__", vars(NonPR))
self.assertNotIn("__callable_proto_members_only__", vars(NonP))
self.assertNotIn("__callable_proto_members_only__", vars(NonPR))

acceptable_extra_attrs = {
'_is_protocol', '_is_runtime_protocol', '__parameters__',
'__subclasshook__', '__abstractmethods__', '_abc_impl',
'__init__', '__annotations__',
}
self.assertLessEqual(vars(NonP).keys(), vars(C).keys() | acceptable_extra_attrs)
self.assertLessEqual(
vars(NonPR).keys(), vars(D).keys() | acceptable_extra_attrs
)

def test_custom_subclasshook(self):
class P(Protocol):
x = 1
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13 changes: 7 additions & 6 deletions Lib/typing.py
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Original file line number Diff line number Diff line change
Expand Up @@ -1779,12 +1779,13 @@ class _ProtocolMeta(ABCMeta):
# but is necessary for several reasons...
def __init__(cls, *args, **kwargs):
super().__init__(*args, **kwargs)
cls.__protocol_attrs__ = _get_protocol_attrs(cls)
# PEP 544 prohibits using issubclass()
# with protocols that have non-method members.
cls.__callable_proto_members_only__ = all(
callable(getattr(cls, attr, None)) for attr in cls.__protocol_attrs__
)
if getattr(cls, "_is_protocol", False):
cls.__protocol_attrs__ = _get_protocol_attrs(cls)
# PEP 544 prohibits using issubclass()
# with protocols that have non-method members.
cls.__callable_proto_members_only__ = all(
callable(getattr(cls, attr, None)) for attr in cls.__protocol_attrs__
)

def __subclasscheck__(cls, other):
if (
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