Python
Python 3.16.0a1 Asyncio Event Loop Policy Removal Breaks pytest-asyncio Suites
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Impact: every test errors, even sync ones. backoff, mock, cached-property and nest-asyncio break too.
From the original report
“With pytest-asyncio 1.4.0 installed, every test errors, even sync ones. backoff, mock, cached-property and nest-asyncio break too.”
Details & sources
- How received
- Imported from Bluesky
- Source published
- Oct 14, 2026
- Observed
- Unknown
- Added to CleanApp
- Oct 14, 2026
- Product connection
- Connected service
- Original issue status
- Unknown
- Resolution
- Unknown
- Verification
- Not independently reproduced
Source count unknown
Why this source type: The author reports observed test errors and package breakages resulting from the removal of the asyncio event loop policy API in Python 3.16.0a1.
CleanApp AI summary
Python 3.16.0a1 Asyncio Event Loop Policy Removal Breaks pytest-asyncio Suites: The removal of asyncio's event loop policy API in Python 3.16.0a1 causes test suites using pytest-asyncio 1.4.0 to completely fail on every test, including synchronous tests. Downstream packages such as backoff, mock, and cached-property are also impacted.
Report counts are not affected-user counts. A closed original issue does not confirm a fix.
Public ID: rpt_19LCXoZXp9komgaM1OHd0Q