3.11.0b1 ValueError "not a valid range"

Sphinx’s CI failed on a PR to fix a typo, but only on 3.11.0b1 with a mysterious error:

ImportError while loading conftest '/home/runner/work/sphinx/sphinx/tests/conftest.py'.
ValueError: line 1-0 is not a valid range

CI link (sorry, I tried to install 3.11.0b1 on windows for a smaller reproducer but my computer disagreed) https://github.com/sphinx-doc/sphinx/runs/6669825488?check_suite_focus=true

Packages

distlib-0.3.4 filelock-3.7.0 packaging-21.3 platformdirs-2.5.2 pluggy-1.0.0 py-1.11.0 pyparsing-3.0.9 six-1.16.0 toml-0.10.2 tox-3.25.0 virtualenv-20.14.1 alabaster==0.7.12,attrs==21.4.0,Babel==2.10.1,certifi==2022.5.18.1,charset-normalizer==2.0.12,Cython==0.29.30,docutils==0.18.1,html5lib==1.1,idna==3.3,imagesize==1.3.0,iniconfig==1.1.1,Jinja2==3.1.2,MarkupSafe==2.1.1,packaging==21.3,pluggy==1.0.0,py==1.11.0,Pygments==2.12.0,pyparsing==3.0.9,pytest==7.1.2,pytz==2022.1,requests==2.27.1,six==1.16.0,snowballstemmer==2.2.0,sphinxcontrib-applehelp==1.0.2,sphinxcontrib-devhelp==1.0.2,sphinxcontrib-htmlhelp==2.0.0,sphinxcontrib-jsmath==1.0.1,sphinxcontrib-qthelp==1.0.3,sphinxcontrib-serializinghtml==1.1.5,tomli==2.0.1,urllib3==1.26.9,webencodings==0.5.1

pytest 7.1.2; ubuntu 18.04.6

My guess is this is an issue with pytest (or 3.11.0b1?) as it failed whilst loading conftest, and nothing changed beyond two typos. I searched for “not a valid range” but didn’t find any prior issues.

A

[nicoddemus]

Thanks @hroncok!

I suppose we can close this then?

[Jean-Abou-Samra]

As helpfully pointed out by @pablogsal on python-dev (https://mail.python.org/archives/list/[e-mail]/thread/VZ222BFFAWW73DYFCR7NZR2C5M3TXD65/), you can work around this issue by invoking pytest with --assert=plain.