Click app help page fails with "format" in GitHub actions workflow

[hakonhagland]

I have this minimal poetry project that includes a minimal click app: https://github.com/hakonhagland/debug-python-click

When I run the app locally (Ubuntu 24.04) it behaves like this (expected output):

$ poetry install
$ poetry run greet --help
Usage: greet [OPTIONS]

Options:
  --name TEXT  Who to greet
  --help       Show this message and exit.

However, when I run the same command from the GitHub action workflow, the output is:

'format'

and the click app exits with code 1.

Environment:

• Python version: 3.12.8
• Click version: 8.1.8

[hakonhagland]

This started to work as expected today. Maybe due to an update/bug fix to poetry or to GitHub action runners?