Hello I m getting the following error `ValueError Task lt Ta

Question

Hello I m getting the following error `ValueError Task lt Task ThinkNumGetHistoryTask gt has retry settings but some upstream dependencies do not have result types` Would anyone know how to address this error I tried adding retry to all the tasks in the flow but didn t seem to resolve the issue

Riley Hun · Answer

My flow looks like this ```token task = ThinkNumGetTokenTask max retries=3 retry delay=timedelta seconds=10 history task = ThinkNumGetHistoryTask max retries=3 retry delay=timedelta seconds=10 with Flow thinknum etl as flow token = token task version=version history = history task dataset id=dataset id version=version token=token ```

josh · Answer

Hi < Riley Hun> this is due to the assumption that in order to retry a task the upstream result needs to be persisted somewhere so when it attempts to retry it can grab that data to start the task run You can read more about results here I do however also think that that shouldn t be a ValueError and instead should only raise a warning because retries have the potential to occur in the same process where the data already lives I m going to make a PR for that real quick

josh · Answer

PR here <https github com PrefectHQ prefect pull 3146>

Riley Hun · Answer

Thanks < josh> Appreciate it Looks like I ll have to start persisting my results for my tasks But in this example 1 how come we don t have to persist the upstream result 1

Riley Hun · Answer

So I did something like this ```token task = ThinkNumGetTokenTask max retries=3 retry delay=timedelta seconds=10 result=GCSResult bucket= prefect history task = ThinkNumGetHistoryTask max retries=3 retry delay=timedelta seconds=10 ``` which I can confirm has resolved the aforementioned error