Bash completion not working for sub-commands

[rgl]

What happened:

bash completions for sub-commands do not show up, e.g., the long options of the ps sub-command do not show up:

root@linux:~# crictl ps --
--config                             --help                               --profile-mem                        --tracing-endpoint
--debug                              --image-endpoint                     --runtime-endpoint                   --tracing-sampling-rate-per-million
--enable-tracing                     --profile-cpu                        --timeout                            --version

What you expected to happen:

I expect completion to restrict the suggested option depending on the context of the partial arguments that are on the command line, just like other cli tool, like kubectl.

How to reproduce it (as minimally and precisely as possible):

See the previous What happened section.

Anything else we need to know?:

This was already reported at #645, which was closed without resolution.

Environment:

• Container runtime or hardware configuration: n/a
• OS (e.g: cat /etc/os-release): n/a
• Kernel (e.g. uname -a): n/a
• Others: n/a