box-builder
copy should respect user and with_user statements
Basically, copy always copies as root right now. If we getuid/getgid a username inside the container right before copying it, we can modify the tar data at just the right time, allowing this to happen appropriately.
This is a fair bit of work.
On second thought, this is a problematic solution. instead, let's give the copy call a hash where they can overwrite user/group.
Blocked by https://github.com/docker/docker/issues/21651, so we need to fix that first.
Will be resolved partially by https://github.com/docker/docker/issues/28923 once it's implemented. Might require some more patches from us depending on design requirements.