gh-140870: PyREPL auto-complete module attributes in import statements by loic-simon · Pull Request #140871 · python/cpython

Tighten the pyrepl completer around a few import-completion edge cases.
Relative imports now share one resolver, find_spec failures no longer
bubble out, failed-import tracking resets when sys.path changes, and
double-tab import actions are cleared once consumed.

The patch also keeps empty message lines intact in reader output and
updates the targeted tests and comments to match the intended behavior.