Python3.11 removed support for the ability to place global flags in regexes anywhere besides the start of the regex (this was deprecated around 3.6).
However, the abandoned extension mdx_partial_gfm which klipper’s mkdocs configuration includes appears to still use this functionality, resulting mkdocs bailing out.
Transcript follows:
aaron@warforged:~/vcs/klipper> git describe --always --tags --long --dirty
v0.11.0-275-g8ef0f7d7
aaron@warforged:~/vcs/klipper> source mkdocs-py310/bin/activate
(mkdocs-py310) aaron@warforged:~/vcs/klipper> mkdocs serve -f docs/_klipper3d/mkdocs.yml
INFO - Building documentation...
INFO - Cleaning site directory
WARNING - Both index.md and readme.md found. Skipping readme.md from /home/aaron/vcs/klipper/docs
INFO - The following pages exist in the docs directory, but are not included in the "nav" configuration:
- index.md
INFO - Documentation built in 0.93 seconds
INFO - [12:52:33] Serving on http://127.0.0.1:8000/
^CINFO - Shutting down...
(mkdocs-py310) aaron@warforged:~/vcs/klipper> deactivate
aaron@warforged:~/vcs/klipper> source mkdocs-py311/bin/activate
(mkdocs-py311) aaron@warforged:~/vcs/klipper> mkdocs serve -f docs/_klipper3d/mkdocs.yml
INFO - Building documentation...
ERROR - Config value: 'markdown_extensions'. Error: global flags not at the start of the expression at position 6
Aborted with 1 Configuration Errors!
(mkdocs-py311) aaron@warforged:~/vcs/klipper>
I’m unsure if the markdown extensions added by this module are actually used anywhere in the docs, so I’m not comfortable making a proposal to remove it at this time.