Deduplicate tasks in plan_step

src/exo/worker/main.py

@@ -10,6 +10,7 @@ from exo.routing.connection_message import ConnectionMessage, ConnectionMessageT
 from exo.shared.apply import apply
 from exo.shared.types.commands import ForwarderCommand, RequestEventLog
 from exo.shared.types.common import NodeId, SessionId
+from exo.shared.types.tasks import TaskId
 from exo.shared.types.events import (
     Event,
     EventId,
@@ -172,6 +173,7 @@ class Worker:
                     self.state = apply(self.state, IndexedEvent(idx=idx, event=event))
 
     async def plan_step(self):
+        seen_tasks: set[TaskId] = set()
         while True:
             await anyio.sleep(0.1)
             # 3. based on the updated state, we plan & execute an operation.
@@ -186,6 +188,10 @@ class Worker:
             )
             if task is None:
                 continue
+            if task.task_id in seen_tasks:
+                logger.warning("Worker tried to plan a duplicate task")
+                continue
+            seen_tasks.add(task.task_id)
             logger.info(f"Worker plan: {task.__class__.__name__}")
             assert task.task_status
             await self.event_sender.send(TaskCreated(task_id=task.task_id, task=task))