Bring your towel and join one of the fastest growing data communities. Welcome to our second-generation open source orchestration platform, a completely rethought approach to dataflow automation.

Prefect Community

Tell me, when executing the construction
with case(list_check(new_events), True):
...
with case(list_check(new_events), False):
....
My task returns False, but for some reason everything that is in the case is not executed,writes skipped

<@U02G49HJKND> I think you would need to call the task before the `with case` context manager.
So instead of `with case(list_check(new_events), False)`: it would be:
```condition = list_check(new_events)
with case(condition, False):
    some_task_on_false()```


here is an example: <https://docs.prefect.io/core/idioms/conditional.html#using-conditional-logic-in-a-flow>

To explain the difference:
• `with case(list_check(new_events), False)` - this passes a task to the case()
• `with case(condition, False)` - this passes data that is a result of the list_check task


```#Если списко не пустой
            tf = list_check(new_events)
            with case(tf, False):

                range_date = pd.date_range(start='2021-08-01', end=datetime.today(), freq='MS') #получаем диапазон месяцкв, с которых необходимо выгрзуить данные
                for date in range_date:
                    
                    new_events_in_app = extract_clickhouse(track_id, events, date, 'event', new_events)
                    tf2 = list_check(new_events)
                    with case(tf2, False):

                        next
                    tf2 = list_check(new_events)
                    with case(tf2, True):

                        merge_data = merge(new_events_in_app, ab_users)
                        load_data(merge_data)

                events_in_app = filter_df(events_in_app, new_events)
                merge_data = merge(events_in_app, ab_users)
                load_data(merge_data)

            tf = list_check(new_events)
            with case(tf, True):
                #Если список пустой, то загружаем суточные данные
                logs(events_in_app)
                merge_data = merge(events_in_app, ab_users)
                load_data(merge_data)```


```@task(name='list_check')      
def list_check(new_event_list):
    tf = len(new_event_list) == 0
    return tf```

<@U02H1A95XDW>
moreover, before this I have the condition
```with case (date_check (end_date), True):
with case (date_check (end_date), False):```
And it successfully fulfills

What do you see when you run flow.visualize()? Does the flow structure look as you would expect?

I think this is because `case` will raise a `SKIP` flag when the condition is not met. SKIP will propagate to downstream tasks. If you need something to run, you can use the `always_run` trigger.