[Bug]: Playwright + AnyIO Loop Conflict on Windows

[HDembinski]

Version

1.58.0

Steps to reproduce

• Clone my Repo https://github.com/HDembinski/playwright_anyio_windows_bug
• Follow instructions in README.md

Expected behavior

Playwright sync tests and AnyIO async tests should be runnable in the same pytest session, independent of test order.

Actual behavior

After a Playwright sync test, AnyIO async tests may fail to create/close their own runner with loop-state errors.

Additional context

• A local workaround that force-clears asyncio internals (asyncio.events._set_running_loop(None)) was attempted but didn't work, because it breaks Playwright teardown (Browser.close: no running event loop).

Environment

- OS: Windows 11 (10.0.22631)
- Python: 3.12.6
- pytest: 9.0.2
- anyio: 4.12.1
- playwright: 1.58.0
- pytest-playwright: 0.7.2