External futures can't be awaited across feeds within the same session

Author: davidhewittCreated Sep 17, 2026Updated Sep 17, 2026

Ran into this reviewing #822

The PR proposes making each feed fully close external futures. I wonder if we should instead support the other direction; it should be valid to keep futures open across feeds:

python

import asyncio

from pydantic_monty import AsyncMonty


async def main():
    ready = asyncio.Event()

    async def fetch():
        await ready.wait()
        return 42

    async with AsyncMonty() as pool:
        async with pool.checkout() as session:
            await session.feed_run('f = fetch()', external_lookup={'fetch': fetch})
            ready.set()
            print(await session.feed_run('await f'))


asyncio.run(main())

Unfortunately, at present the second feed will raise with

RuntimeError: No pending async tasks but ResolveFutures requested

Source: pydantic/monty

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