Fix the case of use decorator directly to raw class and add test case (#4177)

python/ray/function_manager.py

@@ -664,7 +664,11 @@ class FunctionActorManager(object):
                                    function_descriptor.class_name)
         try:
             module = importlib.import_module(module_name)
-            return getattr(module, class_name)._modified_class
+            actor_class = getattr(module, class_name)
+            if isinstance(actor_class, ray.actor.ActorClass):
+                return actor_class._modified_class
+            else:
+                return actor_class
         except Exception:
             logger.exception(
                 "Failed to load actor_class %s.".format(class_name))

python/ray/tests/test_basic.py

@@ -2822,6 +2822,9 @@ class BaseClass(object):
     def __init__(self, data):
         self.data = data
 
+    def get_data(self):
+        return self.data
+
 
 @ray.remote
 class DerivedClass(BaseClass):
@@ -2830,14 +2833,12 @@ class DerivedClass(BaseClass):
         # we use BaseClass directly here.
         BaseClass.__init__(self, data)
 
-    def get_data(self):
-        return self.data
-
 
 def test_load_code_from_local(shutdown_only):
     ray.init(load_code_from_local=True, num_cpus=4)
+    message = "foo"
     # Test normal function.
-    assert ray.get(echo.remote("foo")) == "foo"
+    assert ray.get(echo.remote(message)) == message
     # Test actor class with constructor.
     actor = WithConstructor.remote(1)
     assert ray.get(actor.get_data.remote()) == 1
@@ -2848,3 +2849,7 @@ def test_load_code_from_local(shutdown_only):
     # Test derived actor class.
     actor = DerivedClass.remote(1)
     assert ray.get(actor.get_data.remote()) == 1
+    # Test using ray.remote decorator on raw classes.
+    base_actor_class = ray.remote(num_cpus=1)(BaseClass)
+    base_actor = base_actor_class.remote(message)
+    assert ray.get(base_actor.get_data.remote()) == message