I drop a fix of a Jekyll site failing on Netlify, in case useful for someone else.

The build was crashing with a Ruby error related to missing standard libraries. It turns out Netlify was using Ruby 3.4.x, and some gems that used to be auto-included are no longer there by default.

The fix was simply adding these two lines to the Gemfile:

gem "csv"
gem "logger"

To prevent this from happening again it is possible to pin the version via a .ruby-version.