python

Pydantic v2 discriminated union discriminator missing

PydanticUserError.*discriminator.*not found

Fixes

1.Add Literal type annotation for the discriminator field in each model
2.Ensure the discriminator field name exists in all union members
3.Use Annotated[Union[...], Field(discriminator='type')] syntax

pydanticdiscriminated-union

Related Errors

Asyncio event loop already running

RuntimeError: This event loop is already running

•Use nest_asyncio.apply() to allow nested event loops
•Use asyncio.run_coroutine_threadsafe() instead of asyncio.run()

Coroutine never awaited

RuntimeWarning: coroutine '.*' was never awaited

•Add 'await' before the coroutine call
•Use asyncio.create_task() to schedule the coroutine

Asyncio task was cancelled

asyncio\.CancelledError

•Handle CancelledError in try/except within the task
•Use asyncio.shield() to protect critical sections from cancellation