René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"dataclass(a=nan) == dataclass(a=nan) change in truthnes between 3.12 and 3.13","articleBody":"# Bug report\r\n\r\n### Bug description:\r\n\r\n```python\r\nfrom dataclasses import dataclass\r\n@dataclass\r\nclass a:\r\n    a: float\r\n\r\nnan = float('nan')\r\n```\r\n\r\n### Python 3.12.3\r\n\r\n```pycon\r\n\u003e\u003e\u003e nan == nan\r\nFalse\r\n\u003e\u003e\u003e a(nan) == a(nan)\r\nTrue\r\n```\r\n\r\n\r\n\r\n### Python 3.13.0b2\r\n\r\n```pycon\r\n\u003e\u003e\u003e nan == nan\r\nFalse\r\n\u003e\u003e\u003e a(nan) == a(nan)\r\nFalse\r\n```\r\n\r\n\r\n----\r\n\r\nThe new behavior kinda makes sense, but it is a behavior change nevertheless.\r\n\r\nWas it intentional or accidental? I cannot find anything relevant in https://docs.python.org/3.13/whatsnew/3.13.html\r\n\r\nPossibly related to https://github.com/python/cpython/pull/104904 but I have not yet bisected this.\r\n\r\nThis breaks expectations in the testsuite of cattrs: https://github.com/python-attrs/cattrs/issues/547\r\n\r\n### CPython versions tested on:\r\n\r\n3.13\r\n\r\n### Operating systems tested on:\r\n\r\nLinux","author":{"url":"https://github.com/hroncok","@type":"Person","name":"hroncok"},"datePublished":"2024-06-17T14:34:10.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":11},"url":"https://github.com/120645/cpython/issues/120645"}