René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"warnings.catch_warnings is async-unsafe","articleBody":"\r\n\r\n```python\r\nimport warnings\r\nimport asyncio\r\n\r\nasync def spam():\r\n\twith warnings.catch_warnings(record=True) as ws:\r\n\t\tawait asyncio.sleep(0.1)\r\n\t\tw = Warning(\"12345\")\r\n\t\twarnings.warn(w)\r\n\t\tassert w in (ww.message for ww in ws)\r\n\r\nasync def ham():\r\n\twith warnings.catch_warnings(record=True) as ws:\r\n\t\tawait asyncio.sleep(0.2)\r\n\r\nasync def main():\r\n\tawait asyncio.gather(spam(), ham())\r\n\r\nasyncio.run(main())\r\n```\r\n\r\nDespite technically being documented (\u003chttps://docs.python.org/3/library/warnings.html#warnings.catch_warnings\u003e), this is very error-prone, surprising and not at all useful. The warnings module should probably use `contextvars` to manage the warning handler.","author":{"url":"https://github.com/fstirlitz","@type":"Person","name":"fstirlitz"},"datePublished":"2022-04-13T12:34:49.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":13},"url":"https://github.com/91505/cpython/issues/91505"}