Fix global state actors() call (#7567)

python/ray/state.py

@@ -318,9 +318,9 @@ class GlobalState:
             return {}
         gcs_entries = gcs_utils.GcsEntry.FromString(message)
 
-        assert len(gcs_entries.entries) == 1
+        assert len(gcs_entries.entries) > 0
         actor_table_data = gcs_utils.ActorTableData.FromString(
-            gcs_entries.entries[0])
+            gcs_entries.entries[-1])
 
         actor_info = {
             "ActorID": binary_to_hex(actor_table_data.actor_id),

python/ray/tests/test_global_state.py

@@ -76,6 +76,36 @@ def test_add_remove_cluster_resources(ray_start_cluster_head):
     assert ray.cluster_resources()["CPU"] == 6
 
 
+def test_global_state_actor_table(ray_start_regular):
+    @ray.remote
+    class Actor:
+        def ready(self):
+            pass
+
+    # actor table should be empty at first
+    assert len(ray.actors()) == 0
+
+    # actor table should contain only one entry
+    a = Actor.remote()
+    ray.get(a.ready.remote())
+    assert len(ray.actors()) == 1
+
+    # actor table should contain only this entry
+    # even when the actor goes out of scope
+    del a
+
+    def get_state():
+        return list(ray.actors().values())[0]["State"]
+
+    dead_state = ray.gcs_utils.ActorTableData.DEAD
+    for _ in range(10):
+        if get_state() == dead_state:
+            break
+        else:
+            time.sleep(0.5)
+    assert get_state() == dead_state
+
+
 if __name__ == "__main__":
     import pytest
     import sys