[Core] Force get_actor(name)'s name to be non-empty string (#12218)

java/runtime/src/main/java/io/ray/runtime/RayNativeRuntime.java

@@ -216,6 +216,9 @@ public final class RayNativeRuntime extends AbstractRayRuntime {
   @SuppressWarnings("unchecked")
   @Override
   public <T extends BaseActorHandle> Optional<T> getActor(String name, boolean global) {
+    if (name.isEmpty()) {
+      return Optional.empty();
+    }
     byte[] actorIdBytes = nativeGetActorIdOfNamedActor(name, global);
     ActorId actorId = ActorId.fromBytes(actorIdBytes);
     if (actorId.isNil()) {

python/ray/tests/test_actor_advanced.py

@@ -1032,6 +1032,12 @@ def test_kill(ray_start_regular_shared):
         ray.kill("not_an_actor_handle")
 
 
+def test_get_actor_no_input(ray_start_regular_shared):
+    for bad_name in [None, "", "    "]:
+        with pytest.raises(ValueError):
+            ray.get_actor(bad_name)
+
+
 if __name__ == "__main__":
     import pytest
     sys.exit(pytest.main(["-v", __file__]))

python/ray/worker.py

@@ -1538,6 +1538,8 @@ def get_actor(name):
     Raises:
         ValueError if the named actor does not exist.
     """
+    if not name:
+        raise ValueError("Please supply a non-empty value to get_actor")
     worker = global_worker
     worker.check_connected()
     handle = worker.core_worker.get_named_actor_handle(name)