René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"maximum recursion depth in deepcopy regression","articleBody":"# Bug report\r\n\r\n### Bug description:\r\n\r\nThe following code works on py313 and below (this is a very cut-down version of some code in Matplotilb (`matplotlib.path.Path`)) but hit the maximum recursion depth on main. \r\n\r\n```python\r\n# Add a code block here, if required\r\nimport copy\r\n\r\nclass Test:\r\n    def __init__(self, a, b):\r\n        self.a = a\r\n        self.b = a\r\n        self._state = True\r\n\r\n    def __deepcopy__(self, memo=None):\r\n        p = copy.deepcopy(super(), memo)\r\n        p._state = False\r\n        return p\r\n\r\nt = Test(1, 2)\r\nt2 = copy.deepcopy(t)\r\n\r\n```\r\n\r\nI bisected this to https://github.com/python/cpython/pull/125781/ and suspect the problem is that because it is returning a new object it is escaping the memoization and looping.\r\n\r\nI'm happy to be told we should not be doing this fix it on the Matplotlib side, but I would like to be sure that this was an expected consequence of the change. \r\n\r\nattn @serhiy-storchaka\r\n\r\n\r\n### CPython versions tested on:\r\n\r\n3.14, CPython main branch\r\n\r\n### Operating systems tested on:\r\n\r\nLinux","author":{"url":"https://github.com/tacaswell","@type":"Person","name":"tacaswell"},"datePublished":"2024-11-14T03:56:58.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":9},"url":"https://github.com/126817/cpython/issues/126817"}