Hi I m getting an error I don t understand along with unexpe

Question

Hi I m getting an error I don t understand along with unexpected behavior

Stephen Lloyd · Answer

I have a task called `build task` which accepts 3 parameters ```task results = S3Result bucket=F mybucket prefect config RUN ENV location= prefect results task name txt task def build task creds result datasets builds a list actions data = task results write task list prefect context return actions data``` I execute it as follows ```with Flow PREFECT FLOW NAME storage=STORAGE run config=RUN CONFIG executor=LocalDaskExecutor num workers=8 schedule=PREFECT FLOW SCHEDULE result=task results as flow creds = PrefectSecret some secret app creds = PrefectSecret app secret watermark = SnowflakeQuery datasets = get datasets creds actions response = get actions creds final = build task app creds actions response datasets more stuff ``` I get the following error that I am missing 3 required positional arguments Please note that the task fails but then also succeeds How might I be causing this ``` 2022 04 18 10 00 52+0545 INFO prefect TaskRunner | Task build task Starting task run 2022 04 18 10 00 52+0545 ERROR prefect TaskRunner | Task build task Exception encountered during task execution Traceback most recent call last File Users slloyd projects dwbi orchestration venv lib python3 8 site packages prefect engine task runner py line 880 in get task run state value = prefect utilities executors run task with timeout File Users slloyd projects dwbi orchestration venv lib python3 8 site packages prefect utilities executors py line 468 in run task with timeout return task run args kwargs type ignore TypeError build task missing 3 required positional arguments creds result and datasets 2022 04 18 10 00 52+0545 INFO prefect TaskRunner | Task build task Starting task run 2022 04 18 10 00 53+0545 INFO prefect TaskRunner | Task build task Finished task run for task with final state Failed 2022 04 18 10 01 00+0545 INFO prefect TaskRunner | Task build task Finished task run for task with final state Success ```

Stephen Lloyd · Answer

This is the graphviz representation Not sure why there are two lines some places and not others

Stephen Lloyd · Answer

And not sure why `build task` is duplicated since I only call it once and only refer to it once

Kevin Kho · Answer

Hey < Stephen Lloyd> could you move some of the code to the thread when you get a chance to keep the main channel cleaner I think you might have something like ```with Flow as flow final = build task app creds actions response datasets some other task upstream tasks= build task ``` instead make the upstream task `final` like ```some other task upstream tasks= final ``` this will point to the instance of the task that you called Otherwise a new one will be created because the Flow block makes copies

Stephen Lloyd · Answer

I was doing things like `build task set upstream some task ` later in my code When I removed those everything resolved

Kevin Kho · Answer

Assign the upstream to the variable instead of the task definition and you should get the behavior you want