This issue came to light for me when it was discovered that autocompletion didn't work for a library I help maintain, written mainly in Cython. Cython implements @property-annotated methods on its cdef classes as getset descriptors. The rlcompleter logic doesn't exclude these (like it does regular Python properties) since isinstance(member, property) is False. It then goes on to call the getter, which in some cases (in our library at least) raises an exception. Any exception other than an AttributeError causes the rlcompleter to short circuit completely and not offer any options.

This is a more surgical (rlcompleter-only) solution than what was proposed in #112821. If adding ABCs is preferred, I could do that.

Restore the try/except removed in #27401
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).

#112821 also mentioned:

This might cause false positives for method descriptors though.

I think this is handled here, but I also may not fully understand this specific issue.

• Issue: Reconsider gh-88915 changes rlcompleter since exceptions in descriptors cause auto completion to fail #112821