consider pinning the version of debian used in this docker image

[jgravois]

i found out the hard way today that the latest official python:3.12 docker image is built using Debian 13.

this is problematic because Debian 13 (gettext 0.23) generates slightly different linebreaks when running bin/makemessages.sh than Debian 12 (gettext 0.21).

since we call that same bash script from a github action it seems that the path of least resistance would be pin at Debian 12 for now and wait until Ubuntu 25.04 26.04 (gettext 0.23) is available as a hosted task runner to upgrade.

• https://launchpad.net/ubuntu/plucky/+package/gettext
• https://launchpad.net/ubuntu/resolute/+package/gettext
• https://packages.debian.org/trixie/gettext

[Scotchester]

FWIW, GitHub will not be offering any Ubuntu 25 images. They only support LTS releases. [source]

[jgravois]

GitHub will not be offering any Ubuntu 25 images.

good point. luckily 26.04 also comes bundled with gettext 0.23 too.

i'll update this issue description and the corresponding PR.