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{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"`property` assumes that its subclasses have __dict__","articleBody":"`property`'s `tp_init` has [this code](https://github.com/python/cpython/blob/f042646595d1cdd2ecdc15222b1766f746d010f0/Objects/descrobject.c#L1813-L1832):\r\n\r\n```\r\n    if (Py_IS_TYPE(self, \u0026PyProperty_Type)) {\r\n        Py_XSETREF(self-\u003eprop_doc, prop_doc);\r\n    } else {\r\n        /* If this is a property subclass, put __doc__\r\n           in dict of the subclass instance instead,\r\n           otherwise it gets shadowed by __doc__ in the\r\n           class's dict. */\r\n\r\n        /*...*/\r\n         PyObject_SetAttr((PyObject *)self, \u0026_Py_ID(__doc__), prop_doc);\r\n        /*...*/\r\n    }\r\n```\r\n\r\nThis assumes that subclasses of `property` have a `__dict__` (or a `__doc__` attribute settable by other means). That is the case when subclassed using the `class` statement, but might not be true using C.\r\nA C-API reproducer is at https://github.com/wjakob/inheritance_issue/blob/master/inheritance_issue.c\r\n\r\nI don't see a good way to fix this. We could:\r\n- document that subclasses need to set `Py_TPFLAGS_MANAGED_DICT` (or provide a `__doc__` descriptor), or \r\n- ignore the `AttributeError`, unless `__doc__` was set explicitly?\n\n\u003c!-- gh-pr-number: gh-99058 --\u003e\n* PR: gh-99058\n\u003c!-- /gh-pr-number --\u003e\n\n\n\u003c!-- gh-pr-number: gh-105262 --\u003e\n* PR: gh-105262\n\u003c!-- /gh-pr-number --\u003e\n\n\n\u003c!-- gh-pr-number: gh-105297 --\u003e\n* PR: gh-105297\n\u003c!-- /gh-pr-number --\u003e\n","author":{"url":"https://github.com/encukou","@type":"Person","name":"encukou"},"datePublished":"2022-11-01T14:43:16.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":19},"url":"https://github.com/98963/cpython/issues/98963"}