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bpo-38908: Fix issue when non runtime_protocol failed to raise TypeError (#26067)

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Yurii Karabas 2021-05-12 18:47:49 +03:00 • committed by GitHub
parent 9b06e4b535
commit c40486a32d
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3 changed files with 23 additions and 2 deletions
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12
Lib/typing.py
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@ -1343,14 +1343,14 @@ def _no_init(self, *args, **kwargs):
raise TypeError('Protocols cannot be instantiated')
def _allow_reckless_class_checks():
def _allow_reckless_class_checks(depth=3):
"""Allow instance and class checks for special stdlib modules.
The abc and functools modules indiscriminately call isinstance() and
issubclass() on the whole MRO of a user class, which may contain protocols.
"""
try:
return sys._getframe(3).f_globals['__name__'] in ['abc', 'functools']
return sys._getframe(depth).f_globals['__name__'] in ['abc', 'functools']
except (AttributeError, ValueError): # For platforms without _getframe().
return True
@ -1370,6 +1370,14 @@ class _ProtocolMeta(ABCMeta):
def __instancecheck__(cls, instance):
# We need this method for situations where attributes are
# assigned in __init__.
if (
getattr(cls, '_is_protocol', False) and
not getattr(cls, '_is_runtime_protocol', False) and
not _allow_reckless_class_checks(depth=2)
):
raise TypeError("Instance and class checks can only be used with"
" @runtime_checkable protocols")
if ((not getattr(cls, '_is_protocol', False) or
_is_callable_members_only(cls)) and
issubclass(instance.__class__, cls)):