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gh-105280: Ensure isinstance([], collections.abc.Mapping) always evaluates to False (#105281)

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Alex Waygood 2023-06-05 15:10:49 +01:00 • committed by GitHub
parent 058b960535
commit 08756dbba6
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3 changed files with 38 additions and 8 deletions
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28
Lib/typing.py
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@ -1771,6 +1771,25 @@ def _pickle_pskwargs(pskwargs):
class _ProtocolMeta(ABCMeta):
# This metaclass is somewhat unfortunate,
# but is necessary for several reasons...
def __new__(mcls, name, bases, namespace, /, **kwargs):
if name == "Protocol" and bases == (Generic,):
pass
elif Protocol in bases:
for base in bases:
if not (
base in {object, Generic}
or base.__name__ in _PROTO_ALLOWLIST.get(base.__module__, [])
or (
issubclass(base, Generic)
and getattr(base, "_is_protocol", False)
)
):
raise TypeError(
f"Protocols can only inherit from other protocols, "
f"got {base!r}"
)
return super().__new__(mcls, name, bases, namespace, **kwargs)
def __init__(cls, *args, **kwargs):
super().__init__(*args, **kwargs)
if getattr(cls, "_is_protocol", False):
@ -1906,14 +1925,7 @@ def _proto_hook(other):
if not cls._is_protocol:
return
# ... otherwise check consistency of bases, and prohibit instantiation.
for base in cls.__bases__:
if not (base in (object, Generic) or
base.__module__ in _PROTO_ALLOWLIST and
base.__name__ in _PROTO_ALLOWLIST[base.__module__] or
issubclass(base, Generic) and getattr(base, '_is_protocol', False)):
raise TypeError('Protocols can only inherit from other'
' protocols, got %r' % base)
# ... otherwise prohibit instantiation.
if cls.__init__ is Protocol.__init__:
cls.__init__ = _no_init_or_replace_init