Noticing a change in behaviour for results since upgrading t Prefect Community #ask-community

Noticing a change in behaviour for results since u...

Josh Paulin

10/14/2022, 5:54 PM

Noticing a change in behaviour for results since upgrading to 2.6. A task that would return an empty list now returns

None

. Wondering if this is intentional. Minimal example in the thread. Also found out I can’t downgrade from 2.6 to 2.5 because of what looks like some database migrations? Running

prefect orion database reset -y

on a database with 2.5 after upgrading to 2.6 and it fails.

👀 1

✅ 1

🙏 1

Josh Paulin

10/14/2022, 5:55 PM

Copy code

@task()
def my_task():
    return []


@flow()
def my_flow():
    result = my_task()
    print(result)

In 2.5

results == []

In 2.6

results is None

Zanie

10/14/2022, 5:57 PM

You can downgrade your database on 2.6 then upgrade it on 2.5 and it should work. This change is definitely not intentional. I’ll look into it, thanks for pointing it out!

🙏 1

Josh Paulin

10/14/2022, 5:59 PM

That did the trick

Josh Paulin

10/14/2022, 5:59 PM

thanks!

Zanie

10/14/2022, 6:01 PM

In the meantime you can do

@task(persist_result=True)

as well for a fix.

Zanie

10/14/2022, 6:01 PM

I reproduced successfully and will get a fix out asap.

🙏 2

Zanie

10/14/2022, 6:08 PM

Ah this is a weird edge-case in Pydantic

Zanie

10/14/2022, 6:24 PM

https://github.com/PrefectHQ/prefect/pull/7181

Zanie

10/14/2022, 7:12 PM

Hey! This is fixed in 2.6.1 which is now available.

Zanie

10/14/2022, 7:12 PM

Thanks again for the report.

Josh Paulin

10/14/2022, 7:13 PM

Yep. Just ran the failing test suite against the new version and it’s working!

👏 1

Josh Paulin

10/14/2022, 7:13 PM

My pleasure

Liz McCutcheon

10/20/2022, 3:09 PM

Thank you for this! Was just about to post with the same issue

Zanie

10/20/2022, 3:12 PM

There are some additional minor fixes for results in the latest release as well 🙂

👍 1

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