gh-149167: PyREPL autocomplete imports to only display public members

[edvilme]

Updates PyREPL autocomplete on import statements to only expose public members if declared with __all__

Before

After

• Issue: pyrepl autocomplete from x import <tab> to only display public members #149167

[edvilme]

CC @ambv @pablogsal

[loic-simon]

Two notes:

• The suggested imports are filtered by self.is_suggestion_match later, which means that if a module explicitely exposed a "private" name (starting with an _) in its __all__, it will be excluded unless the user search for private arguments. That may be a case edgy enough to ignore?
• If the user search for a name that can be imported but is not in __all__, do we really want the REPL to hide it? I quite like the current behavior with _-private names (hide them unless explicitely asked for), so maybe we could restrict to __all__ only for bare fron json import completions, and use dir otherwise? This is a more opinionatred question, tied to the debates around PEP 842-44 😅

[edvilme]

Hello @loic-simon thank you for your feedback and for pointing out those overlooks. I would definitely keep an eye out on PEP 842-44 and discussions for many of those decisions.

1. I think you are right in not mixing heuristics. If a module exposes __all__ we should respect those members and not hide regardless of them starting with _ (they are explicitly exposed).
2. This definitely sounds more opinionated and will read the discussions on the PEP as well as other people's thoughts.
3. Will remove the redundant comment ;)

---

Added comment on discussion https://discuss.python.org/t/python-api-exposure-mechanisms-public-internal-determining-status-quo/108869/35