gh-145107: simplify staggered race using eager_start=False

[graingert]

• Issue: simplify asyncio staggered_race #145107

[caje731]

LGTM!

[Copilot]

Pull request overview

This PR simplifies asyncio.staggered.staggered_race() by removing the internal “ok_to_start” synchronization mechanism and instead creating tasks with eager_start=False to avoid eager-execution ordering issues (gh-145107).

Changes:

• Remove the ok_to_start/next_ok_to_start Event gating from the internal run_one_coro() chain.
• Create staggered-race tasks with loop.create_task(..., eager_start=False) to prevent eager execution.
• Add a Misc/NEWS.d entry documenting the change.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 3 comments.

File	Description
Lib/asyncio/staggered.py	Reworks task creation in staggered_race() to use eager_start=False and drops the extra coordination events.
Misc/NEWS.d/next/Library/2026-02-22-11-27-57.gh-issue-145107.ZlQXEZ.rst	Adds a release-note fragment for the staggered_race change.

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[Copilot]

By forcing eager_start=False here, staggered_race will no longer exercise the eager-start path even when an eager task factory is installed; existing regression tests named “with eager tasks” may become less meaningful. Consider adding/adjusting a test that asserts staggered_race passes eager_start=False (e.g., via a task factory that records the eager_start kwarg) so this behavior can’t regress silently.

[github-actions]

This PR is stale because it has been open for 30 days with no activity.