Address comment: Don't change behavior for non-async actor

Closes: ray-project#49451
Signed-off-by: Chi-Sheng Liu <chishengliu@chishengliu.com>

python/ray/actor.py

@@ -27,6 +27,7 @@
     STREAMING_GENERATOR_RETURN,
     ObjectRefGenerator,
     PythonFunctionDescriptor,
+    raise_sys_exit_with_custom_error_message,
 )
 from ray.util.annotations import DeveloperAPI, PublicAPI
 from ray.util.placement_group import _configure_placement_group_based_on_context
@@ -1766,9 +1767,11 @@ def exit_actor():
     This API can be used only inside an actor. Use ray.kill
     API if you'd like to kill an actor using actor handle.
 
-    When the API is called, the actor sets a flag to exit.
-    The worker periodically checks the flag and exits the actor.
-    So there may be some delay before the actor actually exits.
+    When the API is called, if the actor it not async actor,
+    it raises an exception and exits. For async actor,
+    it sets a flag to exit and the worker periodically checks
+    the flag and exits the actor. So there may be some delay
+    before the actor actually exits.
     Any queued methods will fail. Any ``atexit``
     handlers installed in the actor will be run.
 
@@ -1783,4 +1786,6 @@ def exit_actor():
             f"{worker.mode}. Call this API inside an actor methods"
             "if you'd like to exit the actor gracefully."
         )
+    if not worker.core_worker.current_actor_is_asyncio():
+        raise_sys_exit_with_custom_error_message("exit_actor() is called.")
     worker.core_worker.set_current_actor_should_exit()