Handle not executable directories for `os.listdir`

[nineteendo]

Bug report

Bug description:

I have a directory with "rw-" permisions with a file inaccessible.txt:

>>> import os
>>> os.listdir("directory")
['inaccessible.txt']
>>> os.path.exists("directory/inaccessible.txt")
False

That's inconsistent behaviour: os.listdir says directory/inaccessible.txt exists, while os.path.exists says it does not.
This can be solved simply be raising a PermissionError (or a subclass) for os.listdir when the directory is not executable.
I can't think of any situation outside of a CTF where it would be useful to be able to list the files in such directories.

Note that this is different from a directory with "-wx" permisions with a file secret.txt:

>>> import os
>>> os.listdir("directory")
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
PermissionError: [Errno 13] Permission denied: 'directory'
>>> os.path.exists("directory/secret.txt")
True

In this case, files can still be accessed if you know the filename.

CPython versions tested on:

3.12

Operating systems tested on:

macOS

[nineteendo]

@eryksun, what do you think?

[nineteendo]

@terryjreedy, this is technically not related to pathlib. Though it would change the behaviour of pathlib.Path.iterdir().

[barneygale]

os.stat() and os.listdir() propagate errors from your operating system rather than raising OSError artificially. This is not a bug, and you'll need to gather support on the ideas forum first if you want to change it.