fix instance-only async attr

Lib/test/test_unittest/testmock/testasync.py

@@ -300,6 +300,13 @@ def test_spec_normal_methods_on_class_with_mock(self):
         self.assertIsInstance(mock.async_method, AsyncMock)
         self.assertIsInstance(mock.normal_method, Mock)
 
+    def test_spec_async_attributes_instance(self):
+        async_instance = AsyncClass()
+        async_instance.async_func_attr = async_func
+
+        mock_async_instance = Mock(async_instance)
+        self.assertIsInstance(mock_async_instance.async_func_attr, AsyncMock)
+
     def test_spec_mock_type_kw(self):
         def inner_test(mock_type):
             async_mock = mock_type(spec=async_func)

Lib/unittest/mock.py

@@ -506,8 +506,10 @@ def _mock_add_spec(self, spec, spec_set, _spec_as_instance=False,
 
         _spec_class = None
         _spec_signature = None
+        _spec_obj = None
 
         if spec is not None and not _is_list(spec):
+            _spec_obj = spec
             if isinstance(spec, type):
                 _spec_class = spec
             else:
@@ -520,6 +522,7 @@ def _mock_add_spec(self, spec, spec_set, _spec_as_instance=False,
 
         __dict__ = self.__dict__
         __dict__['_spec_class'] = _spec_class
+        __dict__['_spec_obj'] = _spec_obj
         __dict__['_spec_set'] = spec_set
         __dict__['_spec_signature'] = _spec_signature
         __dict__['_mock_methods'] = spec
@@ -1012,7 +1015,7 @@ def _get_child_mock(self, /, **kw):
         For non-callable mocks the callable variant will be used (rather than
         any custom subclass)."""
         _new_name = kw.get("_new_name")
-        _spec_val = getattr(self.__dict__["_spec_class"], _new_name, None)
+        _spec_val = getattr(self.__dict__["_spec_obj"], _new_name, None)
         if _spec_val is not None and asyncio.iscoroutinefunction(_spec_val):
             return AsyncMock(**kw)