Hi, I can't make transaction idempotency work. It seems like

txn.is_committed()

always returns false even though I can see a record written with the expected key in the storage directory. I tried the example from the docs:

from prefect import task, flow
from prefect.transactions import transaction


@task
def download_data():
    """Imagine this downloads some data from an API"""
    return "some data"


@task
def write_data(data: str):
    """This writes the data to a file"""
    with open("data.txt", "w") as f:
        f.write(data)


@flow(log_prints=True)
def pipeline():
    with transaction(key="download-and-write-data") as txn:
        if txn.is_committed():
            print("Data file has already been written. Exiting early.")
            return
        data = download_data()
        write_data(data)


if __name__ == "__main__":
    pipeline()

I don't get the expected print statement and the download/write tasks are executed.

hi @Theom - I think there was a bug at fault here, which I hopefully fixed in this PR (on macOS) you can try the fix by copying your example to your clipboard and running

pbpaste | uv run --with git+<https://github.com/PrefectHQ/prefect.git@refs/pull/17541/head> -

Thanks for the lightning fast reaction! I'm not on macOS though, I'll wait for the release where this PR will be included.

the only macos part was the pbpaste, you should be able to do

pip install git+<https://github.com/PrefectHQ/prefect.git@refs/pull/17541/head>

and then your script but sounds good! thanks for the follow up

Thank you, will try this or the next dev release. In fact I had another transaction-related question here. Is there a way to assign a result to a transaction and then retrieve it in subsequent runs in case it's already committed?

would you be willing to make a discussion about this? just more discoverable that way and easier to link to PRs

Sure!

thank you!