Fix issue where new_messages is None (#183)

PrefectHQ · Jun 25, 2024 · 360e0cf · 360e0cf
1 parent 0485706
commit 360e0cf
Showing 1 changed file with 4 additions and 2 deletions.
diff --git a/src/controlflow/controllers/controller.py b/src/controlflow/controllers/controller.py
@@ -320,7 +320,8 @@ async def run_async(self) -> list[MessageType]:
                     any(t.is_incomplete() for t in self.tasks) and not self._should_stop
                 ):
                     new_messages = await self.run_once_async()
-                    messages.extend(new_messages)
+                    if new_messages:
+                        messages.extend(new_messages)
             self._should_stop = False
             return messages
 
@@ -337,6 +338,7 @@ def run(self) -> list[MessageType]:
         with self.flow:
             while any(t.is_incomplete() for t in self.tasks) and not self._should_stop:
                 new_messages = self.run_once()
-                messages.extend(new_messages)
+                if new_messages:
+                    messages.extend(new_messages)
         self._should_stop = False
         return messages