gtk3 frontend gives no widget for answering a boolean prompt

Test package noisy-fake-driver from https://launchpad.net/~vorlon/+archive/ubuntu/debconf-tests/+packages does not reproduce the problem in an upgraded cosmic environment.

dpkg-reconfigure docker.io also does not reproduce the original problem.

Either the problem was present in bionic and fixed in cosmic; or it is a consequence of the debconf frontend being started up in the middle of the release upgrade and having a somehow incoherent filesystem.

I was unable to recreate this today when performing an upgrade from Ubuntu 18.04 to Ubuntu 18.10. I did ensure that all updates were installed before I performed the upgrade between releases, something you may not have been forced to do as the ubuntu-release-upgrader change may not have landed the day you encountered this.

This was an up to date 18.04 system before upgrading. Missing SRUs were not the cause.

I will try to reproduce this myself (but probably not until next week).

Have not found the time to reproduce this and there have been no other reports. It definitely happened, but my best guess is a one-off gtk glitch that we may never be able to diagnose. Closing this as invalid; if someone else can reproduce it, we can of course reopen.

I also experience this problem on Ubuntu Xenial. The prompt is:

 ┌───────────────────────────────────────────────────────────┤ Configuring docker.io ├────────────────────────────────────────────────────────────┐
  │ │
  │ If Docker is upgraded without restarting the Docker daemon, Docker will often have trouble starting new containers, and in some cases even │
  │ maintaining the containers it is currently running. See https://launchpad.net/bugs/1658691 for an example of this breakage. │
  │ │
  │ Normally, upgrading the package would simply restart the associated daemon(s). In the case of the Docker daemon, that would also imply │
  │ stopping all running containers (which will only be restarted if they're part of a "service", have an appropriate restart policy configured, │
  │ or have some other means of being restarted such as an external systemd unit). │
  │ │
  │ Automatically restart Docker daemon? │
  │ │
  │ <Yes> <No> │
  │ │
  └────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┘

It's seems to be not configurable by dpkg --set-selections:

root@server# dpkg --get-selections docker.io
docker.io install

I could upload a vagrant box to demonstrate this issue when running apt-get upgrade -y. I try to automate the upgrade process, but this atm blocks the upgrade and CI pipelines with interactive prompt. I'm also trying to build a workaround wrapper with expect.

The version is:
Setting up docker.io (18.09.7-0ubuntu1~16.04.7) ...