pydantic_graph: asyncio.get_event_loop() is deprecated since python 3.12

[JohnUiterwyk]

Initial Checks

• I confirm that I'm using the latest version of Pydantic AI

Description

asyncio.get_event_loop() has been deprecated since version 3.12

The following code at line 15 in pydantic_graph/_utils.py emits a deprecation warning
event_loop = asyncio.get_event_loop()

Python docs recommend using asyncio.get_running_loop() instead.
https://docs.python.org/3/library/asyncio-eventloop.html#asyncio.get_event_loop

Example Code

from pydantic_ai import Agent
from pydantic_ai.models.test import TestModel
agent = Agent(TestModel())
agent.run_sync('hi')"


  /home/user/.local/lib/python3.13/site-packages/pydantic_graph/_utils.py:15: DeprecationWarning: There is no current event loop
    event_loop = asyncio.get_event_loop()

Python, Pydantic AI & LLM client version

python=3.13
pydantic=2.10.6
pydantic-ai-slim=0.0.42

[Kludex]

Thanks for the report. 🙏

[JohnUiterwyk]

Thank you @Kludex! I forked and cloned the project, and made the one line change as suggested in the docs and then ran the test suite (was a good motivator to get a dev env for the project setup). I saw what seemed like dozens of test failures, showing clearly the simple change was not like for like (which wasn’t surprising I guess, but also indicating it may not be a good first issue to contribute on!)

If it’s not too deep of a topic, would you mind sharing what the implications of the change was within the context of pydantic-ai and the graph sub system, and how you resolved it?
(if only for the educational benefit for myself and anyone else who stumbles on this thread after hitting the same issue in some other project)

edit: fixed the user @ mention for kludex.

[Kludex]

I don't think you pinged me on your message. 👀

Usually, issues related to asyncio are not the easiest. Now we always create a new event loop instead of calling get_event_loop. In case of Python 3.11+, we use the new Runner asyncio API.

[Kludex]

I'm opening it again because I had to revert the commit. I'm not sure if there's a way for us to solve this without proper sync support.