k0s k0s exits with status code 0 when encountering unknown subcommands

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Version

v1.23.3+k0s.1

Platform

No LSB modules are available.
Distributor ID: NixOS
Description:    NixOS 21.11 (Porcupine)
Release:        21.11
Codename:       porcupine

What happened?

Unknown subcommands are ignored by the k0s CLI and treated as if they haven't been given at all. This may get in the way when invoking k0s from scripts and other automation tools.

Steps to reproduce

Test case:

run_test() {
  for cmd in \
    airgap \
    api \
    backup \
    completion \
    config \
    controller \
    ctr \
    docs \
    etcd \
    help \
    install \
    kubeconfig \
    kubectl \
    reset \
    restore \
    start \
    status \
    stop \
    sysinfo \
    token \
    version \
    worker; do
    echo Executing k0s "$cmd" i_certainly_dont_exist ... 1>&2
    if ./k0s-v1.23.3+k0s.1-amd64 "$cmd" i_certainly_dont_exist 2>/dev/null; then
      echo k0s "$cmd" i_certainly_dont_exist succeeded unexpectedly ... 1>&2
    fi
  done
}

run_test 2>&1 | grep 'succeeded unexpectedly'

gives

k0s airgap i_certainly_dont_exist succeeded unexpectedly ...
k0s config i_certainly_dont_exist succeeded unexpectedly ...
k0s etcd i_certainly_dont_exist succeeded unexpectedly ...
k0s help i_certainly_dont_exist succeeded unexpectedly ...
k0s install i_certainly_dont_exist succeeded unexpectedly ...
k0s kubeconfig i_certainly_dont_exist succeeded unexpectedly ...
k0s sysinfo i_certainly_dont_exist succeeded unexpectedly ...
k0s token i_certainly_dont_exist succeeded unexpectedly ...
k0s version i_certainly_dont_exist succeeded unexpectedly ...

Expected behavior

Unknown subcommands result in a non-zero exit code, and the help text is written to stderr.

Actual behavior

The general CLI help text is written to stdout and k0s exits with a zero exit code.

Screenshots and logs

No response

Additional context

No response

Mar 24 '22 12:03 twz123

k0sctl relies on using the --help of subcommands to figure out if the k0s version has that subcommand or not.