Exit with non-zero codes when user input is invalid

[vainu-lauri]

This pr contains my attempt of fixing the exit codes of invalid CLI commands (as defined in the issue #2087).

As you can probably see from the submission I'm no golang expert so this will probably need a bit more or less tuning.

One thing that comes to mind is the philosophical question whether we should consider an incomplete but correct command (like kind delete) as a success or a failure. The current implementation in this PR considers it as a failure (I think this way just seemed right).

Closes #2087

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[vainu-lauri]

/check-cla

[BenTheElder]

/ok-to-test

[BenTheElder]

One thing that comes to mind is the philosophical question whether we should consider an incomplete but correct command (like kind delete) as a success or a failure. The current implementation in this PR considers it as a failure (I think this way just seemed right).

I think if we have to show help and the user did not explicitly request help we should consider it a failure, +1
We can make it not a failure in the future if the command starts to do something useful without further subcommand.

[vainu-lauri]

/retest

[aojea]

should we add a expectErr field and do some positive testing? i..e commands that we know can't fail

[BenTheElder]

only if we turn this into an integration test, which can be in a follow-up (let's not be running real commands in unit tests)

[BenTheElder]

thanks so much!
sorry for the delay getting to this, I've been tied up with some big changes in kubernetes/kubernetes before code freeze hits there 😅
/lgtm
/approve

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[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: BenTheElder, vainu-lauri

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[aojea]

/retest
tests timing out in the 1.20 job
job timed out for the ipv6 job

[BenTheElder]

we should probably up the limit, looks like it only took 40m

[vainu-lauri]

No problem at all, thanks for having a look. Happy to help!

What comes to the positive testing we could have the kind versionand kind help tested without needing integrations.
That would add a little bit of coverage on that side of the commands as well.

[BenTheElder]

if you're up for another PR that sounds reasonable to me, good point!