stubtest: ignore setattr and delattr inherited from object

__setattr__ and __delattr__ from object are special cased by
type checkers, so defining them on an inheriting class,
even with the same signature, has a different meaning.

Author: tungol

mypy/stubtest.py

@@ -571,9 +571,23 @@ def verify_typeinfo(
 
         # If it came from the metaclass, consider the runtime_attr to be MISSING
         # for a more accurate message
-        if runtime_attr is not MISSING and type(runtime) is not runtime:
-            if getattr(runtime_attr, "__objclass__", None) is type(runtime):
-                runtime_attr = MISSING
+        if (
+            runtime_attr is not MISSING
+            and type(runtime) is not runtime
+            and getattr(runtime_attr, "__objclass__", None) is type(runtime)
+        ):
+            runtime_attr = MISSING
+
+        # __setattr__ and __delattr__ on object are a special case,
+        # so if we only have these methods inherited from there, pretend that
+        # we don't have them. See python/typeshed#7385.
+        if (
+            entry in ("__setattr__", "__delattr__")
+            and runtime_attr is not MISSING
+            and runtime is not object
+            and getattr(runtime_attr, "__objclass__", None) is object
+        ):
+            runtime_attr = MISSING
 
         # Do not error for an object missing from the stub
         # If the runtime object is a types.WrapperDescriptorType object

mypy/test/teststubtest.py

@@ -1470,6 +1470,24 @@ def __call__(*args, **kwds): ...
             runtime="class ClassWithMetaclassOverride: ...",
             error="ClassWithMetaclassOverride.__call__",
         )
+        # Test that we ignore object.__setattr__ and object.__delattr__ inheritance
+        yield Case(
+            stub="""
+            from typing import Any
+            class FakeSetattrClass:
+                def __setattr__(self, name: str, value: Any, /) -> None: ...
+            """,
+            runtime="class FakeSetattrClass: ...",
+            error="FakeSetattrClass.__setattr__",
+        )
+        yield Case(
+            stub="""
+            class FakeDelattrClass:
+                def __delattr__(self, name: str, /) -> None: ...
+            """,
+            runtime="class FakeDelattrClass: ...",
+            error="FakeDelattrClass.__delattr__",
+        )
 
     @collect_cases
     def test_missing_no_runtime_all(self) -> Iterator[Case]: