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Don't override task factory's eager_start default - #779
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PR MagicStack#748 introduced a regression by passing `eager_start=None` to the task factory when not provided by the caller. On Python 3.14 this is interpreted as `False`, overriding `asyncio.eager_task_factory`'s default of `eager_start=True` and resulting in non-eager tasks. On Python 3.13, it's a `TypeError` , since `eager_task_factory` and user factories with the `(loop, coro, *, name=None, context=None)` signature do not accept an `eager_start` argument at all. Forward `eager_start` to the factory and to `Task` only when provided by the caller. This matches the behaviour of `asyncio`'s loop. Add tests for behaviour when `eager_start=False` and when not provided.
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PR #748 introduced a regression by passing
eager_start=Noneto thetask factory when not provided by the caller. On Python 3.14 this is
interpreted as
False, overridingasyncio.eager_task_factory'sdefault of
eager_start=Trueand resulting in non-eager tasks. OnPython 3.13, it's a
TypeError, sinceeager_task_factoryand userfactories with the
(loop, coro, *, name=None, context=None)signaturedo not accept an
eager_startargument at all.Forward
eager_startto the factory and toTaskonly when provided bythe caller. This matches the behaviour of
asyncio's loop.Add tests for behaviour when
eager_start=Falseand when not provided.Fixes #754 (the TypeError on Python 3.13).
Disclosure: Bug found and patch and tests were written by Claude Fable 5.1. But I can confirm the bug on 3.14 and that this fixes it, and the reason for the regression is obvious.