asyncio task_factory does not receive name parameter

[ordinary-jamie]

Bug report

Bug description:

The asyncio.BaseEventLoop.create_task loop method does not pass the name parameter to the task factory

There is two issues with this:

1. Inconsistent with the eager task factory signature
2. Users cannot easily configure the task name through just the task factory interface

A simple demonstration of this issue:

import asyncio


def new_task(loop, coro, name=None, context=None):
    assert name is not None  # Will raise

    return asyncio.Task(coro, loop=loop, name=name, context=context)


async def main():
    loop = asyncio.get_event_loop()
    loop.set_task_factory(new_task)
    loop.create_task(asyncio.sleep(1), name="task1")


if __name__ == "__main__":
    asyncio.run(main())

Also see: #112623 (comment)

CPython versions tested on:

3.12

Operating systems tested on:

macOS

Linked PRs

• gh-113050: Pass name to BaseEventLoop task factory #113051

[gvanrossum]

(I am not ready for a review yet, but as I see you are fond of force-pushing, can you please not do that? It makes the review cycle more complicated. It is also unnecessary since at the end we always squash-merge.)

[gvanrossum]

Hm. set_task_factory is documented as taking a function of two positional arguments (loop, coro) and one keyword arg (context=None). If we start adding name=... to the call, we break this contract. In particular, working user code that declares a task factory as a function with exactly the suggested signature will raise an exception when called with name=....

I don't think we can change this. There are similar backwards compatibility issues with other APIs outside asyncio where we have a similar constraint that prevents us to change the signature of a user-provided callback (e.g. __exit__), and we just live with it.

[ordinary-jamie]

In particular, working user code that declares a task factory as a function with exactly the suggested signature will raise an exception when called with name=....

Yup this would be a breaking change for users. I can close/park the PR and issue :)

Is there anything we need to do around eager_task_factory? The signature is misleading as it does have the name kwarg

asyncio.eager_task_factory(loop, coro, *, name=None, context=None)
A task factory for eager task execution.
When using this factory (via loop.set_task_factory(asyncio.eager_task_factory)),

[gvanrossum]

Is there anything we need to do around eager_task_factory? The signature is misleading as it does have the name kwarg

I think we should leave it alone, since 3.12 went out with this signature, and people could be calling it directly rather than passing it to set_task_factory().

I think closing the PR is the only thing to do.