Nov 24, 2023 · Nov 23, 2023 · Nov 23, 2023 · Nov 23, 2023 · Nov 23, 2023 · Nov 23, 2023
diff --git a/Lib/test/test_typing.py b/Lib/test/test_typing.py
        self.assertIsInstance(Foo(), ProtocolWithMixedMembers)
        self.assertNotIsInstance(42, ProtocolWithMixedMembers)

    def test_protocol_issubclass_error_message(self):
        class Vec2D(Protocol):
            x: float
            y: float

            def square_norm(self) -> float:
                return self.x ** 2 + self.y ** 2

        expected_error_message = (
            "Protocols with non-method members don't support issubclass()."
            " Non-method members: {'x', 'y'}."
        )
        self.assertRaisesRegex(TypeError, f'^{re.escape(expected_error_message)}$')
        self.assertEqual(Vec2D.__protocol_attrs__, {'x', 'y', 'square_norm'})

 class GenericTests(BaseTestCase):

diff --git a/Lib/typing.py b/Lib/typing.py
                not cls.__callable_proto_members_only__
                and cls.__dict__.get("__subclasshook__") is _proto_hook
            ):
                non_method_attrs = {
                    attr for attr in cls.__protocol_attrs__
                    if not callable(getattr(cls, attr, None))
                }
                raise TypeError(
                    "Protocols with non-method members don't support issubclass()"
                    "Protocols with non-method members don't support issubclass()."
                    f" Non-method members: {non_method_attrs}."
                )
            if not getattr(cls, '_is_runtime_protocol', False):
                raise TypeError(
diff --git a/Misc/NEWS.d/next/Library/2023-11-23-17-25-27.gh-issue-112345.FFApHx.rst b/Misc/NEWS.d/next/Library/2023-11-23-17-25-27.gh-issue-112345.FFApHx.rst
 Improve error message when trying to call :func:`issubclass` against a :class:`typing.Protocol` that has non-method members.
 Patch by Randolf Scholz.
Original file line number	Diff line number	Diff line change
Expand Up		@@ -4091,6 +4091,20 @@ def method(self) -> None: ...
		self.assertIsInstance(Foo(), ProtocolWithMixedMembers)
		self.assertNotIsInstance(42, ProtocolWithMixedMembers)

		def test_protocol_issubclass_error_message(self):
		class Vec2D(Protocol):
		x: float
		y: float

		def square_norm(self) -> float:
		return self.x 2 + self.y 2

		expected_error_message = (
		"Protocols with non-method members don't support issubclass()."
		" Non-method members: {'x', 'y'}."
		)
		self.assertRaisesRegex(TypeError, f'^{re.escape(expected_error_message)}$')
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		self.assertEqual(Vec2D.__protocol_attrs__, {'x', 'y', 'square_norm'})

		class GenericTests(BaseTestCase):

Expand Down
Original file line number	Diff line number	Diff line change
Expand Up		@@ -1828,8 +1828,13 @@ def __subclasscheck__(cls, other):
		not cls.__callable_proto_members_only__
		and cls.__dict__.get("__subclasshook__") is _proto_hook
		):
		non_method_attrs = {
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		attr for attr in cls.__protocol_attrs__
		if not callable(getattr(cls, attr, None))
		}
		raise TypeError(
		"Protocols with non-method members don't support issubclass()"
		"Protocols with non-method members don't support issubclass()."
		f" Non-method members: {non_method_attrs}."
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		)
		if not getattr(cls, '_is_runtime_protocol', False):
		raise TypeError(
Expand Down
Original file line number	Diff line number	Diff line change
		@@ -0,0 +1,2 @@
		Improve error message when trying to call :func:`issubclass` against a :class:`typing.Protocol` that has non-method members.
		Patch by Randolf Scholz.