[Bug] workflow.in_workflow() expects to be called in a thread with a running event loop

[dmarcato]

What are you really trying to do?

I have a sync activity that triggers a utility method that needs to make sure it's not being called inside a workflow.
At a high level, the code is structured like this:

# activities.py
@activity.defn
def my_activity(arg: MyArg):
    utility.do_stuff()

# utility.py
def do_stuff():
    if workflow.in_workflow():
        raise RuntimeError("Can not call from inside a workflow")

Describe the bug

The activity triggers the following error:

RuntimeError
no running event loop

which can be traced to the maybe_current() method:

Minimal Reproduction

The example above should be enough to reproduce.
The worker is configured with a ThreadPoolExecutor to execute the sync activities.

Environment/Versions

• Temporal Version: Python 1.11.0
• Running inside Docker

[cretz]

Thanks, good find. We expect this to be able to be called from all contexts and we need to return False (via None on maybe_current) if there is no running loop. We will fix.