Docker - completely delete /var/lib/apt/lists when creating image

[liamjones]

When ansible.builtin.apt is run with a cache_valid_time it will not do an apt update before attempting to install a package if the cache was recently updated.

It does this by first checking to see if /var/lib/apt/periodic/update-success-stamp exists and, if so, uses its last modified time to compare against now - cache_valid_time. I believe this file is only created if update-notifier-common is installed and ran a periodic update check so isn't directly relevant here.

However, if the above file doesn't exist, the ansible apt task then falls back to looking at the last modified time of /var/lib/apt/lists to work out if the cache has been updated recently. See https://github.com/ansible/ansible/blob/0aa8afbaf4739510a96c9727237792a95c8855c3/lib/ansible/modules/apt.py#L1174

If the docker driver builds a container and then molecule runs an apt task to install a package with a cache_valid_time set, it'll error out stating the package isn't available because it believes the cache is up to date, but it has been removed.

By deleting the whole lists directory, the task will, the first time, realise it needs to run an update first (and subsequent tasks will be able to make use of the recently retrieved cache for speed).

I've checked, and removing the whole directory seems fine; apt recreates it when you next run apt update.

[github-actions]

Label error. Requires exactly 1 of: bug, enhancement, major, minor, patch, skip-changelog. Found:

[liamjones]

Ugh, while this works fine for apt being run directly, ansible's apt task falls over when you entirely remove the lists directory.

Seems to be an old issue, moving this PR to draft for now as a result: ansible/ansible#61176