python · randolf-scholz · Nov 23, 2023 · Nov 23, 2023 · Nov 23, 2023 · Nov 23, 2023
@@ -4091,6 +4091,46 @@ def method(self) -> None: ...
         self.assertIsInstance(Foo(), ProtocolWithMixedMembers)
         self.assertNotIsInstance(42, ProtocolWithMixedMembers)
 
+    def test_protocol_special_members(self):
+        # See https://github.com/python/cpython/issues/112319
+
+        T_co = TypeVar("T_co", covariant=True)
+
+        @runtime_checkable
+        class GenericIterable(Protocol[T_co]):
+            def __class_getitem__(cls, item): ...
+            def __iter__(self): ...
+
+        self.assertIsInstance([1,2,3], GenericIterable)
+        self.assertNotIsInstance("123", GenericIterable)  # str is not a generic type!
+
+        class TakesKWARGS(Protocol):
+            def __init__(self, **kwargs): ...  # NOTE: For static checking.
+
+        self.assertEqual(TakesKWARGS.__protocol_attrs__, {"__init__"})
+
+    def test_protocol_special_attributes(self):
+        class Documented(Protocol):
+            """Matches classes that have a docstring."""
+            __doc__: str  # NOTE: For static checking, undocumented classes have __doc__ = None.
+
+        self.assertEqual(Documented.__protocol_attrs__, {"__doc__"})
+
+        @runtime_checkable
+        class Slotted(Protocol):
+            """Matches classes that have a __slots__ attribute."""
+            __slots__: tuple
+
+        class Unslotted:
+            pass
+
+        class WithSlots:
+            __slots__ = ("foo", "bar")
+
+        self.assertEqual(Slotted.__protocol_attrs__, {"__slots__"})
+        self.assertNotIsInstance(Unslotted(), Slotted)
+        self.assertIsInstance(WithSlots(), Slotted)
+
 
 class GenericTests(BaseTestCase):
 

@@ -1675,13 +1675,65 @@ class _TypingEllipsis:
 
 _SPECIAL_NAMES = frozenset({
     '__abstractmethods__', '__annotations__', '__dict__', '__doc__',
-    '__init__', '__module__', '__new__', '__slots__',
-    '__subclasshook__', '__weakref__', '__class_getitem__',
-    '__match_args__',
+    '__module__', '__slots__', '__match_args__', '__qualname__',
+})
+_SPECIAL_CALLABLE_NAMES = frozenset({
+    '__init__', '__new__', '__subclasshook__','__class_getitem__', '__weakref__',
 })
 
 # These special attributes will be not collected as protocol members.
 EXCLUDED_ATTRIBUTES = _TYPING_INTERNALS | _SPECIAL_NAMES | {'_MutableMapping__marker'}
+EXCLUDED_MEMBERS = EXCLUDED_ATTRIBUTES | _SPECIAL_CALLABLE_NAMES
+
+
+def _get_local_members(namespace):
+    """Collect the specified attributes from a classes' namespace."""
+    annotations = namespace.get("__annotations__", {})
+    attrs = (namespace.keys() | annotations.keys()) - EXCLUDED_MEMBERS
+    # exclude special "_abc_" attributes
+    return {attr for attr in attrs if not attr.startswith('_abc_')}
+
+
+def _get_local_protocol_members(namespace):
+    """Collect the specified attributes from the protocols' namespace."""
+    # annotated attributes are always considered protocol members
+    annotations = namespace.get("__annotations__", {})
+    # only namespace members outside the excluded set are considered protocol members
+    return (namespace.keys() - EXCLUDED_ATTRIBUTES) | annotations.keys()
+
+
+def _get_parent_members(cls):
+    """Collect protocol members from parents of arbitrary class object.
+
+    This includes names actually defined in the class dictionary, as well
+    as names that appear in annotations. Special names (above) are skipped.
+    """
+    attrs = set()
+    for base in cls.__mro__[1:-1]:  # without self and object
+        if base.__name__ in {'Protocol', 'Generic'}:
+            continue
+        elif getattr(base, "_is_protocol", False):
+            attrs |= getattr(base, "__protocol_attrs__", set())
+        else:  # get from annotations
+            attrs |= _get_local_members(base.__dict__)
+    return attrs
+
+
+def _get_cls_members(cls):
+    """Collect protocol members from an arbitrary class object.
+
+    This includes names actually defined in the class dictionary, as well
+    as names that appear in annotations. Special names (above) are skipped.
+    """
+    attrs = set()
+    for base in cls.__mro__[:-1]:  # without object
+        if base.__name__ in {'Protocol', 'Generic'}:
+            continue
+        elif getattr(base, "_is_protocol", False):
+            attrs |= getattr(base, "__protocol_attrs__", set())
+        else:
+            attrs |= _get_local_members(base.__dict__)
+    return attrs
 
 
 def _get_protocol_attrs(cls):
@@ -1696,7 +1748,7 @@ def _get_protocol_attrs(cls):
             continue
         annotations = getattr(base, '__annotations__', {})
         for attr in (*base.__dict__, *annotations):
-            if not attr.startswith('_abc_') and attr not in EXCLUDED_ATTRIBUTES:
+            if not attr.startswith('_abc_') and attr not in EXCLUDED_MEMBERS:
                 attrs.add(attr)
     return attrs
 
@@ -1804,10 +1856,14 @@ def __new__(mcls, name, bases, namespace, /, **kwargs):
                     )
         return super().__new__(mcls, name, bases, namespace, **kwargs)
 
-    def __init__(cls, *args, **kwargs):
-        super().__init__(*args, **kwargs)
-        if getattr(cls, "_is_protocol", False):
-            cls.__protocol_attrs__ = _get_protocol_attrs(cls)
+    def __init__(cls, name, bases, namespace, **kwds):
+        super().__init__(name, bases, namespace, **kwds)
+        if getattr(cls, "_is_protocol", False) and cls.__name__ != "Protocol":
+            cls.__protocol_attrs__ = (
+                _get_local_protocol_members(namespace) | _get_parent_members(cls)
+            )
+            # local_attrs =  _get_local_protocol_members(namespace)
+            # cls.__protocol_attrs__ = local_attrs.union(*map(_get_cls_members, bases))
             # PEP 544 prohibits using issubclass()
             # with protocols that have non-method members.
             cls.__callable_proto_members_only__ = all(

diff --git a/Misc/NEWS.d/next/Library/2023-11-23-17-43-28.gh-issue-112319.MdsRx7.rst b/Misc/NEWS.d/next/Library/2023-11-23-17-43-28.gh-issue-112319.MdsRx7.rst
@@ -0,0 +1,22 @@
+:class:`Protocol` classes now allow specification of previously excluded attributes and methods.
+
+Example::
+
+    class Documented(Protocol):
+        """A Protocol for documented classes."""
+        __doc__: str
+
+    class Slotted(Protocol):
+        """A Protocol for classes with __slots__."""
+        __slots__: tuple[str, ...]
+
+    @runtime_checkable
+    class GenericIterable(Protocol):
+        """An iterable that must also be a generic type."""
+        def __class_getitem__(cls, item): ...
+        def __iter__(self): ...
+
+    assert isinstance(["a", "b", "c"], GenericIterable)  # ✅
+    assert not isinstance("abc", GenericIterable)  # ✅
+
+Patch by Randolf Scholz.