When creating a vagrant box with packer, one of my provisioning script does VISUAL="sed -i -e '/use-dpkg-feature/ s/yes/no/'" dpkg-reconfigure -f editor localepurge

And this is what I get from debconf:

debconf: unable to initialize frontend: Dialog
debconf: (Dialog frontend will not work on a dumb terminal, an emacs shell buffer, or without a controlling terminal.)
debconf: falling back to frontend: Readline
debconf: unable to initialize frontend: Readline
debconf: (This frontend requires a controlling tty.)
debconf: falling back to frontend: Teletype
    vagrant: Installing packages