From 07a30791562f626c63d3f85a5c87dd411e3108cc Mon Sep 17 00:00:00 2001
From: AlexWaygood <alex.waygood@gmail.com>
Date: Sat, 20 Jan 2024 13:19:37 +0000
Subject: [PATCH 1/6] Backport recent improvements to the implementation of
`Protocol`
---
CHANGELOG.md | 11 +++++
src/test_typing_extensions.py | 73 +++++++++++++++++++++-------
src/typing_extensions.py | 91 +++++++++++++++++++++++++++--------
3 files changed, 136 insertions(+), 39 deletions(-)
diff --git a/CHANGELOG.md b/CHANGELOG.md
index fedc2a3f..c3957a29 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,14 @@
+# Unreleased
+
+- Speedup `issubclass()` checks against simple runtime-checkable protocols by
+ around 6% (backporting https://github.com/python/cpython/pull/112717, by Alex
+ Waygood).
+- Fix a regression in the implementation of protocols where `typing.Protocol`
+ classes that were not marked as `@runtime-checkable` would be unnecessarily
+ introspected, potentially causing exceptions to be raised if the protocol had
+ problematic members. Patch by Alex Waygood, backporting
+ https://github.com/python/cpython/pull/113401.
+
# Release 4.9.0 (December 9, 2023)
This feature release adds `typing_extensions.ReadOnly`, as specified
diff --git a/src/test_typing_extensions.py b/src/test_typing_extensions.py
index 77876b7f..11208d95 100644
--- a/src/test_typing_extensions.py
+++ b/src/test_typing_extensions.py
@@ -1872,18 +1872,6 @@ class E(C, BP): pass
self.assertNotIsInstance(D(), E)
self.assertNotIsInstance(E(), D)
- def test_runtimecheckable_on_typing_dot_Protocol(self):
- @runtime_checkable
- class Foo(typing.Protocol):
- x: int
-
- class Bar:
- def __init__(self):
- self.x = 42
-
- self.assertIsInstance(Bar(), Foo)
- self.assertNotIsInstance(object(), Foo)
-
def test_typing_dot_runtimecheckable_on_Protocol(self):
@typing.runtime_checkable
class Foo(Protocol):
@@ -2817,8 +2805,8 @@ def meth(self): pass # noqa: B027
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))
+ self.assertNotIn("__non_callable_proto_members__", vars(NonP))
+ self.assertNotIn("__non_callable_proto_members__", vars(NonPR))
acceptable_extra_attrs = {
'_is_protocol', '_is_runtime_protocol', '__parameters__',
@@ -2891,11 +2879,26 @@ def __subclasshook__(cls, other):
@skip_if_py312b1
def test_issubclass_fails_correctly(self):
@runtime_checkable
- class P(Protocol):
+ class NonCallableMembers(Protocol):
x = 1
+
+ class NotRuntimeCheckable(Protocol):
+ def callable_member(self) -> int: ...
+
+ @runtime_checkable
+ class RuntimeCheckable(Protocol):
+ def callable_member(self) -> int: ...
+
class C: pass
- with self.assertRaisesRegex(TypeError, r"issubclass\(\) arg 1 must be a class"):
- issubclass(C(), P)
+
+ # These three all exercise different code paths,
+ # but should result in the same error message:
+ for protocol in NonCallableMembers, NotRuntimeCheckable, RuntimeCheckable:
+ with self.subTest(proto_name=protocol.__name__):
+ with self.assertRaisesRegex(
+ TypeError, r"issubclass\(\) arg 1 must be a class"
+ ):
+ issubclass(C(), protocol)
def test_defining_generic_protocols(self):
T = TypeVar('T')
@@ -3456,6 +3459,7 @@ def method(self) -> None: ...
@skip_if_early_py313_alpha
def test_protocol_issubclass_error_message(self):
+ @runtime_checkable
class Vec2D(Protocol):
x: float
y: float
@@ -3471,6 +3475,39 @@ def square_norm(self) -> float:
with self.assertRaisesRegex(TypeError, re.escape(expected_error_message)):
issubclass(int, Vec2D)
+ def test_nonruntime_protocol_interaction_with_evil_classproperty(self):
+ class classproperty:
+ def __get__(self, instance, type):
+ raise RuntimeError("NO")
+
+ class Commentable(Protocol):
+ evil = classproperty()
+
+ # recognised as a protocol attr,
+ # but not actually accessed by the protocol metaclass
+ # (which would raise RuntimeError) for non-runtime protocols.
+ # See gh-113320
+ self.assertEqual(get_protocol_members(Commentable), {"evil"})
+
+ def test_runtime_protocol_interaction_with_evil_classproperty(self):
+ class CustomError(Exception): pass
+
+ class classproperty:
+ def __get__(self, instance, type):
+ raise CustomError
+
+ with self.assertRaises(TypeError) as cm:
+ @runtime_checkable
+ class Commentable(Protocol):
+ evil = classproperty()
+
+ exc = cm.exception
+ self.assertEqual(
+ exc.args[0],
+ "Failed to determine whether protocol member 'evil' is a method member"
+ )
+ self.assertIs(type(exc.__cause__), CustomError)
+
class Point2DGeneric(Generic[T], TypedDict):
a: T
@@ -5263,7 +5300,7 @@ def test_typing_extensions_defers_when_possible(self):
'SupportsRound', 'Unpack',
}
if sys.version_info < (3, 13):
- exclude |= {'NamedTuple', 'Protocol'}
+ exclude |= {'NamedTuple', 'Protocol', 'runtime_checkable'}
if not hasattr(typing, 'ReadOnly'):
exclude |= {'TypedDict', 'is_typeddict'}
for item in typing_extensions.__all__:
diff --git a/src/typing_extensions.py b/src/typing_extensions.py
index 1666e96b..7de29cd5 100644
--- a/src/typing_extensions.py
+++ b/src/typing_extensions.py
@@ -473,7 +473,7 @@ def clear_overloads():
"_is_runtime_protocol", "__dict__", "__slots__", "__parameters__",
"__orig_bases__", "__module__", "_MutableMapping__marker", "__doc__",
"__subclasshook__", "__orig_class__", "__init__", "__new__",
- "__protocol_attrs__", "__callable_proto_members_only__",
+ "__protocol_attrs__", "__non_callable_proto_members__",
"__match_args__",
}
@@ -521,6 +521,22 @@ def _no_init(self, *args, **kwargs):
if type(self)._is_protocol:
raise TypeError('Protocols cannot be instantiated')
+ def _type_check_issubclass_arg_1(arg):
+ """Raise TypeError if `arg` is not an instance of `type`
+ in `issubclass(arg, <protocol>)`.
+
+ In most cases, this is verified by type.__subclasscheck__.
+ Checking it again unnecessarily would slow down issubclass() checks,
+ so, we don't perform this check unless we absolutely have to.
+
+ For various error paths, however,
+ we want to ensure that *this* error message is shown to the user
+ where relevant, rather than a typing.py-specific error message.
+ """
+ if not isinstance(arg, type):
+ # Same error message as for issubclass(1, int).
+ raise TypeError('issubclass() arg 1 must be a class')
+
# Inheriting from typing._ProtocolMeta isn't actually desirable,
# but is necessary to allow typing.Protocol and typing_extensions.Protocol
# to mix without getting TypeErrors about "metaclass conflict"
@@ -551,11 +567,6 @@ def __init__(cls, *args, **kwargs):
abc.ABCMeta.__init__(cls, *args, **kwargs)
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 cls is Protocol:
@@ -564,26 +575,23 @@ def __subclasscheck__(cls, other):
getattr(cls, '_is_protocol', False)
and not _allow_reckless_class_checks()
):
- if not isinstance(other, type):
- # Same error message as for issubclass(1, int).
- raise TypeError('issubclass() arg 1 must be a class')
+ if not getattr(cls, '_is_runtime_protocol', False):
+ _type_check_issubclass_arg_1(other)
+ raise TypeError(
+ "Instance and class checks can only be used with "
+ "@runtime_checkable protocols"
+ )
if (
- not cls.__callable_proto_members_only__
+ # this attribute is set by @runtime_checkable:
+ cls.__non_callable_proto_members__
and cls.__dict__.get("__subclasshook__") is _proto_hook
):
- non_method_attrs = sorted(
- attr for attr in cls.__protocol_attrs__
- if not callable(getattr(cls, attr, None))
- )
+ _type_check_issubclass_arg_1(other)
+ non_method_attrs = sorted(cls.__non_callable_proto_members__)
raise TypeError(
"Protocols with non-method members don't support issubclass()."
f" Non-method members: {str(non_method_attrs)[1:-1]}."
)
- if not getattr(cls, '_is_runtime_protocol', False):
- raise TypeError(
- "Instance and class checks can only be used with "
- "@runtime_checkable protocols"
- )
return abc.ABCMeta.__subclasscheck__(cls, other)
def __instancecheck__(cls, instance):
@@ -610,7 +618,8 @@ def __instancecheck__(cls, instance):
val = inspect.getattr_static(instance, attr)
except AttributeError:
break
- if val is None and callable(getattr(cls, attr, None)):
+ # this attribute is set by @runtime_checkable:
+ if val is None and attr not in cls.__non_callable_proto_members__:
break
else:
return True
@@ -678,8 +687,48 @@ def __init_subclass__(cls, *args, **kwargs):
cls.__init__ = _no_init
+if sys.version_info >= (3, 13):
+ runtime_checkable = typing.runtime_checkable
+else:
+ def runtime_checkable(cls):
+ """Mark a protocol class as a runtime protocol.
+ Such protocol can be used with isinstance() and issubclass().
+ Raise TypeError if applied to a non-protocol class.
+ This allows a simple-minded structural check very similar to
+ one trick ponies in collections.abc such as Iterable.
+ For example::
+ @runtime_checkable
+ class Closable(Protocol):
+ def close(self): ...
+ assert isinstance(open('/some/file'), Closable)
+ Warning: this will check only the presence of the required methods,
+ not their type signatures!
+ """
+ if not issubclass(cls, typing.Generic) or not getattr(cls, '_is_protocol', False):
+ raise TypeError('@runtime_checkable can be only applied to protocol classes,'
+ ' got %r' % cls)
+ cls._is_runtime_protocol = True
+ # PEP 544 prohibits using issubclass()
+ # with protocols that have non-method members.
+ # See gh-113320 for why we compute this attribute here,
+ # rather than in `_ProtocolMeta.__init__`
+ cls.__non_callable_proto_members__ = set()
+ for attr in cls.__protocol_attrs__:
+ try:
+ is_callable = callable(getattr(cls, attr, None))
+ except Exception as e:
+ raise TypeError(
+ f"Failed to determine whether protocol member {attr!r} "
+ "is a method member"
+ ) from e
+ else:
+ if not is_callable:
+ cls.__non_callable_proto_members__.add(attr)
+ return cls
+
+
# The "runtime" alias exists for backwards compatibility.
-runtime = runtime_checkable = typing.runtime_checkable
+runtime = runtime_checkable
# Our version of runtime-checkable protocols is faster on Python 3.8-3.11
From c9fdbc103c1a707669932ee42ce52e375582c6db Mon Sep 17 00:00:00 2001
From: AlexWaygood <alex.waygood@gmail.com>
Date: Sat, 20 Jan 2024 15:06:34 +0000
Subject: [PATCH 2/6] Restore being able to use
`typing_extensions.runtime_checkable` on `typing.Protocol`
---
src/test_typing_extensions.py | 12 ++++
src/typing_extensions.py | 125 +++++++++++++++++-----------------
2 files changed, 75 insertions(+), 62 deletions(-)
diff --git a/src/test_typing_extensions.py b/src/test_typing_extensions.py
index 11208d95..58dc1851 100644
--- a/src/test_typing_extensions.py
+++ b/src/test_typing_extensions.py
@@ -1872,6 +1872,18 @@ class E(C, BP): pass
self.assertNotIsInstance(D(), E)
self.assertNotIsInstance(E(), D)
+ def test_runtimecheckable_on_typing_dot_Protocol(self):
+ @runtime_checkable
+ class Foo(typing.Protocol):
+ x: int
+
+ class Bar:
+ def __init__(self):
+ self.x = 42
+
+ self.assertIsInstance(Bar(), Foo)
+ self.assertNotIsInstance(object(), Foo)
+
def test_typing_dot_runtimecheckable_on_Protocol(self):
@typing.runtime_checkable
class Foo(Protocol):
diff --git a/src/typing_extensions.py b/src/typing_extensions.py
index 7de29cd5..10c5795d 100644
--- a/src/typing_extensions.py
+++ b/src/typing_extensions.py
@@ -687,6 +687,52 @@ def __init_subclass__(cls, *args, **kwargs):
cls.__init__ = _no_init
+if hasattr(typing, "is_protocol"):
+ is_protocol = typing.is_protocol
+ get_protocol_members = typing.get_protocol_members
+else:
+ def is_protocol(tp: type, /) -> bool:
+ """Return True if the given type is a Protocol.
+
+ Example::
+
+ >>> from typing_extensions import Protocol, is_protocol
+ >>> class P(Protocol):
+ ... def a(self) -> str: ...
+ ... b: int
+ >>> is_protocol(P)
+ True
+ >>> is_protocol(int)
+ False
+ """
+ return (
+ isinstance(tp, type)
+ and getattr(tp, '_is_protocol', False)
+ and tp is not Protocol
+ and tp is not typing.Protocol
+ )
+
+ def get_protocol_members(tp: type, /) -> typing.FrozenSet[str]:
+ """Return the set of members defined in a Protocol.
+
+ Example::
+
+ >>> from typing_extensions import Protocol, get_protocol_members
+ >>> class P(Protocol):
+ ... def a(self) -> str: ...
+ ... b: int
+ >>> get_protocol_members(P)
+ frozenset({'a', 'b'})
+
+ Raise a TypeError for arguments that are not Protocols.
+ """
+ if not is_protocol(tp):
+ raise TypeError(f'{tp!r} is not a Protocol')
+ if hasattr(tp, '__protocol_attrs__'):
+ return frozenset(tp.__protocol_attrs__)
+ return frozenset(_get_protocol_attrs(tp))
+
+
if sys.version_info >= (3, 13):
runtime_checkable = typing.runtime_checkable
else:
@@ -708,22 +754,23 @@ def close(self): ...
raise TypeError('@runtime_checkable can be only applied to protocol classes,'
' got %r' % cls)
cls._is_runtime_protocol = True
- # PEP 544 prohibits using issubclass()
- # with protocols that have non-method members.
- # See gh-113320 for why we compute this attribute here,
- # rather than in `_ProtocolMeta.__init__`
- cls.__non_callable_proto_members__ = set()
- for attr in cls.__protocol_attrs__:
- try:
- is_callable = callable(getattr(cls, attr, None))
- except Exception as e:
- raise TypeError(
- f"Failed to determine whether protocol member {attr!r} "
- "is a method member"
- ) from e
- else:
- if not is_callable:
- cls.__non_callable_proto_members__.add(attr)
+ if isinstance(cls, _ProtocolMeta):
+ # PEP 544 prohibits using issubclass()
+ # with protocols that have non-method members.
+ # See gh-113320 for why we compute this attribute here,
+ # rather than in `_ProtocolMeta.__init__`
+ cls.__non_callable_proto_members__ = set()
+ for attr in get_protocol_members(cls):
+ try:
+ is_callable = callable(getattr(cls, attr, None))
+ except Exception as e:
+ raise TypeError(
+ f"Failed to determine whether protocol member {attr!r} "
+ "is a method member"
+ ) from e
+ else:
+ if not is_callable:
+ cls.__non_callable_proto_members__.add(attr)
return cls
@@ -2978,52 +3025,6 @@ def __ror__(self, left):
return typing.Union[left, self]
-if hasattr(typing, "is_protocol"):
- is_protocol = typing.is_protocol
- get_protocol_members = typing.get_protocol_members
-else:
- def is_protocol(tp: type, /) -> bool:
- """Return True if the given type is a Protocol.
-
- Example::
-
- >>> from typing_extensions import Protocol, is_protocol
- >>> class P(Protocol):
- ... def a(self) -> str: ...
- ... b: int
- >>> is_protocol(P)
- True
- >>> is_protocol(int)
- False
- """
- return (
- isinstance(tp, type)
- and getattr(tp, '_is_protocol', False)
- and tp is not Protocol
- and tp is not typing.Protocol
- )
-
- def get_protocol_members(tp: type, /) -> typing.FrozenSet[str]:
- """Return the set of members defined in a Protocol.
-
- Example::
-
- >>> from typing_extensions import Protocol, get_protocol_members
- >>> class P(Protocol):
- ... def a(self) -> str: ...
- ... b: int
- >>> get_protocol_members(P)
- frozenset({'a', 'b'})
-
- Raise a TypeError for arguments that are not Protocols.
- """
- if not is_protocol(tp):
- raise TypeError(f'{tp!r} is not a Protocol')
- if hasattr(tp, '__protocol_attrs__'):
- return frozenset(tp.__protocol_attrs__)
- return frozenset(_get_protocol_attrs(tp))
-
-
if hasattr(typing, "Doc"):
Doc = typing.Doc
else:
From 8dd0b5b51ebfa428d21f2a1d4639ecec9b3a15e0 Mon Sep 17 00:00:00 2001
From: AlexWaygood <alex.waygood@gmail.com>
Date: Sat, 20 Jan 2024 15:08:31 +0000
Subject: [PATCH 3/6] reduce diff
---
src/typing_extensions.py | 94 ++++++++++++++++++++--------------------
1 file changed, 47 insertions(+), 47 deletions(-)
diff --git a/src/typing_extensions.py b/src/typing_extensions.py
index 10c5795d..1f03f15e 100644
--- a/src/typing_extensions.py
+++ b/src/typing_extensions.py
@@ -687,52 +687,6 @@ def __init_subclass__(cls, *args, **kwargs):
cls.__init__ = _no_init
-if hasattr(typing, "is_protocol"):
- is_protocol = typing.is_protocol
- get_protocol_members = typing.get_protocol_members
-else:
- def is_protocol(tp: type, /) -> bool:
- """Return True if the given type is a Protocol.
-
- Example::
-
- >>> from typing_extensions import Protocol, is_protocol
- >>> class P(Protocol):
- ... def a(self) -> str: ...
- ... b: int
- >>> is_protocol(P)
- True
- >>> is_protocol(int)
- False
- """
- return (
- isinstance(tp, type)
- and getattr(tp, '_is_protocol', False)
- and tp is not Protocol
- and tp is not typing.Protocol
- )
-
- def get_protocol_members(tp: type, /) -> typing.FrozenSet[str]:
- """Return the set of members defined in a Protocol.
-
- Example::
-
- >>> from typing_extensions import Protocol, get_protocol_members
- >>> class P(Protocol):
- ... def a(self) -> str: ...
- ... b: int
- >>> get_protocol_members(P)
- frozenset({'a', 'b'})
-
- Raise a TypeError for arguments that are not Protocols.
- """
- if not is_protocol(tp):
- raise TypeError(f'{tp!r} is not a Protocol')
- if hasattr(tp, '__protocol_attrs__'):
- return frozenset(tp.__protocol_attrs__)
- return frozenset(_get_protocol_attrs(tp))
-
-
if sys.version_info >= (3, 13):
runtime_checkable = typing.runtime_checkable
else:
@@ -760,7 +714,7 @@ def close(self): ...
# See gh-113320 for why we compute this attribute here,
# rather than in `_ProtocolMeta.__init__`
cls.__non_callable_proto_members__ = set()
- for attr in get_protocol_members(cls):
+ for attr in cls.__protocol_attrs__:
try:
is_callable = callable(getattr(cls, attr, None))
except Exception as e:
@@ -3025,6 +2979,52 @@ def __ror__(self, left):
return typing.Union[left, self]
+if hasattr(typing, "is_protocol"):
+ is_protocol = typing.is_protocol
+ get_protocol_members = typing.get_protocol_members
+else:
+ def is_protocol(tp: type, /) -> bool:
+ """Return True if the given type is a Protocol.
+
+ Example::
+
+ >>> from typing_extensions import Protocol, is_protocol
+ >>> class P(Protocol):
+ ... def a(self) -> str: ...
+ ... b: int
+ >>> is_protocol(P)
+ True
+ >>> is_protocol(int)
+ False
+ """
+ return (
+ isinstance(tp, type)
+ and getattr(tp, '_is_protocol', False)
+ and tp is not Protocol
+ and tp is not typing.Protocol
+ )
+
+ def get_protocol_members(tp: type, /) -> typing.FrozenSet[str]:
+ """Return the set of members defined in a Protocol.
+
+ Example::
+
+ >>> from typing_extensions import Protocol, get_protocol_members
+ >>> class P(Protocol):
+ ... def a(self) -> str: ...
+ ... b: int
+ >>> get_protocol_members(P)
+ frozenset({'a', 'b'})
+
+ Raise a TypeError for arguments that are not Protocols.
+ """
+ if not is_protocol(tp):
+ raise TypeError(f'{tp!r} is not a Protocol')
+ if hasattr(tp, '__protocol_attrs__'):
+ return frozenset(tp.__protocol_attrs__)
+ return frozenset(_get_protocol_attrs(tp))
+
+
if hasattr(typing, "Doc"):
Doc = typing.Doc
else:
From 0d92d3bda68a1e016b1f30641e6250260d253138 Mon Sep 17 00:00:00 2001
From: AlexWaygood <alex.waygood@gmail.com>
Date: Sat, 20 Jan 2024 15:10:01 +0000
Subject: [PATCH 4/6] add comment
---
src/typing_extensions.py | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/src/typing_extensions.py b/src/typing_extensions.py
index 1f03f15e..1e7e9e33 100644
--- a/src/typing_extensions.py
+++ b/src/typing_extensions.py
@@ -708,6 +708,9 @@ def close(self): ...
raise TypeError('@runtime_checkable can be only applied to protocol classes,'
' got %r' % cls)
cls._is_runtime_protocol = True
+
+ # Only execute the following block if it's a typing_extensions.Protocol class.
+ # typing.Protocol classes don't need it.
if isinstance(cls, _ProtocolMeta):
# PEP 544 prohibits using issubclass()
# with protocols that have non-method members.
@@ -725,6 +728,7 @@ def close(self): ...
else:
if not is_callable:
cls.__non_callable_proto_members__.add(attr)
+
return cls
From ecd711bfe88f4839797311cdee1956daaa58d6c1 Mon Sep 17 00:00:00 2001
From: AlexWaygood <alex.waygood@gmail.com>
Date: Sat, 20 Jan 2024 15:11:57 +0000
Subject: [PATCH 5/6] fix docstring
---
src/typing_extensions.py | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/src/typing_extensions.py b/src/typing_extensions.py
index 1e7e9e33..4007594c 100644
--- a/src/typing_extensions.py
+++ b/src/typing_extensions.py
@@ -692,15 +692,20 @@ def __init_subclass__(cls, *args, **kwargs):
else:
def runtime_checkable(cls):
"""Mark a protocol class as a runtime protocol.
+
Such protocol can be used with isinstance() and issubclass().
Raise TypeError if applied to a non-protocol class.
This allows a simple-minded structural check very similar to
one trick ponies in collections.abc such as Iterable.
+
For example::
+
@runtime_checkable
class Closable(Protocol):
def close(self): ...
+
assert isinstance(open('/some/file'), Closable)
+
Warning: this will check only the presence of the required methods,
not their type signatures!
"""
From c858502ddf1bf3474511c29b871400539f1c0acc Mon Sep 17 00:00:00 2001
From: Jelle Zijlstra <jelle.zijlstra@gmail.com>
Date: Sat, 20 Jan 2024 09:55:03 -0800
Subject: [PATCH 6/6] Update CHANGELOG.md
---
CHANGELOG.md | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/CHANGELOG.md b/CHANGELOG.md
index c3957a29..be1c16d6 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,7 +4,7 @@
around 6% (backporting https://github.com/python/cpython/pull/112717, by Alex
Waygood).
- Fix a regression in the implementation of protocols where `typing.Protocol`
- classes that were not marked as `@runtime-checkable` would be unnecessarily
+ classes that were not marked as `@runtime_checkable` would be unnecessarily
introspected, potentially causing exceptions to be raised if the protocol had
problematic members. Patch by Alex Waygood, backporting
https://github.com/python/cpython/pull/113401.