New GitHub issue #119032 from hroncok:<br>
<hr>
<pre>
# Bug report
### Bug description:
I was debugging a certain issue in setuptools tests in Python 3.13.0b1 REPL:
```pycon
>>> import os, posixpath
>>> path = r'\foo/bar.txt'
>>> os.path.pardir in path.split(posixpath.sep)
(no output)
```
I was worried. Shouldn't the result be True or False exclusively?
```pycon
>>> os.path.pardir in path.split(posixpath.sep)
>>> os.path.pardir in path.split(posixpath.sep)
False
>>> os.path.pardir in path.split(posixpath.sep)
False
>>> os.path.pardir in path.split(posixpath.sep)
False
>>> os.path.pardir in path.split(posixpath.sep)
False
>>> os.path.pardir in path.split(posixpath.sep)
False
```
Huh? Let's try again with something simpler:
```pycon
>>> 'a' in 'aaa'
>>> 'a' in 'aaa'
True
```
This appears to happen entirely at random for me.
````
$ python3.13
Python 3.13.0b1 (main, May 9 2024, 00:00:00) [GCC 14.1.1 20240507 (Red Hat 14.1.1-1)] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> 'a' in 'aaa'
>>> 'a' in 'aaa'
True
$ python3.13
Python 3.13.0b1 (main, May 9 2024, 00:00:00) [GCC 14.1.1 20240507 (Red Hat 14.1.1-1)] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> 'a' in 'aaa'
True
>>> 'a' in 'aaa'
True
```
This is on Fedora Linux 39.
python3.13-3.13.0~b1-2.fc41.x86_64
readline-8.2-6.fc39.x86_64
ncurses-libs-6.4-7.20230520.fc39.1.x86_64
### CPython versions tested on:
3.13
### Operating systems tested on:
Linux
</pre>
<hr>
<a href="https://github.com/python/cpython/issues/119032">View on GitHub</a>
<p>Labels: type-bug</p>
<p>Assignee: </p>