René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"Reconsider gh-88915 changes rlcompleter since exceptions in descriptors cause auto completion to fail","articleBody":"# Bug report\r\n\r\n### Bug description:\r\n\r\nIn BPO [44752](https://bugs.python.org/issue44752) (#88915), it was reported that tab completions execute `@property` getters. This was fixed in two stages:\r\n\r\n1. https://github.com/python/cpython/pull/27401: no longer call property getters\r\n2. https://github.com/python/cpython/pull/27401: No longer catch errors raised by a call to getattr.\r\n\r\nIt looks like when investigating/solving this issue, it was unconsidered that `@property` isn't the only case where calling an underlying method might be undesirable. For example, in the [NVDA project](https://github.com/nvaccess/nvda), we have the following non-data descriptor (simplified for clarity):\r\n\r\n```python\r\nclass Getter:\r\n    def __init__(self, fget):\r\n        self.fget = fget\r\n\r\n    def __get__(self, instance, owner):\r\n        if isinstance(self.fget, classmethod):\r\n            return self.fget.__get__(instance, owner)()\r\n        elif instance is None:\r\n            return self\r\n        return self.fget(instance)\r\n\r\n\r\nclass SomeClass:\r\n    @Getter\r\n    def some_prop(self):\r\n        raise NotImplementedError\r\n```\r\n\r\nIf we'd create an instance of SomeClass and try to autocomplete, `rlcompleter.Completer.attr_matches` would fail with the `NotImplementedError` raised by `some_prop`\r\n\r\nI'd propose one of the following:\r\n\r\n1. Restore the try/except removed in #27401\r\n2. Create abstract classes for descriptors in _collections_abc (e.g. ImplementsGet, ImplementsSet, ImplementsDelete) and in rlcompleter, rather than checking for `isinstance(obj, property)`, use `isinstance(obj, ImplementsGet)`. This might cause false positives for method descriptors though.\r\n\r\n### CPython versions tested on:\r\n\r\n3.11\r\n\r\n### Operating systems tested on:\r\n\r\nWindows\n\n\u003c!-- gh-linked-prs -->\n### Linked PRs\n* gh-149577\n* gh-149656\n* gh-149657\n* gh-149658\n\u003c!-- /gh-linked-prs -->\n","author":{"url":"https://github.com/LeonarddeR","@type":"Person","name":"LeonarddeR"},"datePublished":"2023-12-07T07:02:03Z","url":"https://github.com/python/cpython/issues/112821"}