gh-132493: Avoid eager import of annotationlib in typing (again)

Lib/test/test_typing.py

@@ -3149,6 +3149,21 @@ def x(self): ...
         with self.assertRaisesRegex(TypeError, only_classes_allowed):
             issubclass(1, BadPG)
 
+    def test_lazy_evaluation_with_subprotocols(self):
+        @runtime_checkable
+        class Base(Protocol):
+            x: int
+
+        @runtime_checkable
+        class Child(Base, Protocol):
+            y: str
+
+        class Capybara:
+            x = 43
+
+        self.assertIsInstance(Capybara(), Base)
+        self.assertNotIsInstance(Capybara(), Child)
+
     def test_implicit_issubclass_between_two_protocols(self):
         @runtime_checkable
         class CallableMembersProto(Protocol):
@@ -3843,6 +3858,7 @@ def meth(self): pass
             '_is_protocol', '_is_runtime_protocol', '__parameters__',
             '__init__', '__annotations__', '__subclasshook__', '__annotate__',
             '__annotations_cache__', '__annotate_func__',
+            '__protocol_attrs_cache__',
         }
         self.assertLessEqual(vars(NonP).keys(), vars(C).keys() | acceptable_extra_attrs)
         self.assertLessEqual(

Lib/typing.py

@@ -1801,9 +1801,13 @@ def _get_protocol_attrs(cls):
     for base in cls.__mro__[:-1]:  # without object
         if base.__name__ in {'Protocol', 'Generic'}:
             continue
-        annotations = _lazy_annotationlib.get_annotations(
-            base, format=_lazy_annotationlib.Format.FORWARDREF
-        )
+        try:
+            annotations = base.__annotations__
+        except Exception:
+            # Only go through annotationlib to handle deferred annotations if we need to
+            annotations = _lazy_annotationlib.get_annotations(
+                base, format=_lazy_annotationlib.Format.FORWARDREF
+            )
         for attr in (*base.__dict__, *annotations):
             if not attr.startswith('_abc_') and attr not in EXCLUDED_ATTRIBUTES:
                 attrs.add(attr)
@@ -2020,14 +2024,15 @@ def _proto_hook(cls, other):
                 break
 
             # ...or in annotations, if it is a sub-protocol.
-            if (
-                issubclass(other, Generic)
-                and getattr(other, "_is_protocol", False)
-                and attr in _lazy_annotationlib.get_annotations(
-                    base, format=_lazy_annotationlib.Format.FORWARDREF
-                )
-            ):
-                break
+            if issubclass(other, Generic) and getattr(other, "_is_protocol", False):
+                try:
+                    annos = base.__annotations__
+                except Exception:
+                    annos = _lazy_annotationlib.get_annotations(
+                        base, format=_lazy_annotationlib.Format.FORWARDREF
+                    )
+                if attr in annos:
+                    break
         else:
             return NotImplemented
     return True