Sentinel in namespace path breaks NamespaceReader

[jaraco]

Bug report

Bug description:

As reported in python/importlib_resources#311 and highlighted by python/importlib_resources#318, when an editable install adds a sentinel value to a namespace path, it can break the NamespaceReader when that value doesn't resolve to a pathlib.Path or zipfile.Path.

This code was introduced in #106531 and fixed in importlib_resources 6.4.5.

CPython versions tested on:

3.13

Operating systems tested on:

macOS

Linked PRs

• gh-123987: Fix NotADirectoryError in NamespaceReader when sentinel present #124018