There were a long story related to broken shell completions because of replacing `docker-compose` (which had completions) with `docker compose` (which doesn't had completions because of docker plugin architecture), but finally this really annoying issue was resolved in latest versions. The problem is current ebuild does not install latest completions, thus (at least in zsh) `docker compose <Tab>` still doesn't work. The workaround is to run `docker completion zsh > ~/.zsh/completions/_docker`, but docker-cli ebuild should install this into /usr/share/zsh/site-functions/_docker (and probably do the same for bash/fish too).
One thing is I'm unsure is this works even if docker installed before docker-compose:2, probably worth to test.
