Comment 5 for bug 1883978

After a discussion I have with Rheinard and Rick, we decided to keep docker.io package the way it is right now because this was a decision made sometime ago when we started to diverge from Debian. Long story short, in Ubuntu we use all the dependencies vendored (and not as regular dependencies on other debian packages) because we decided to keep backporting new versions of docker.io to supported LTS releases, and in the worst case scenario we would need to backport +120 packages (in the case where all the dependencies also need update). As you may know Golang dependencies are volatile and upstream developers update them, usually in their vendor directory, constantly. This is good because regardless of the LTS version you are using you have an updated version of docker.io.

The side effect of this decision is that library packages which depend on docker.io library might need to declare dependency on other packages that would be provided by the docker.io library package if we were in sync with Debian. I've seen some packages in this situation and for now the workaround is to add those dependencies like Andreas mentioned in the bug description. If the number of packages needing this workaround increases considerably we should revisit this topic.