fix-pkg-staticcheck and remove the repeat code

[tanjunchen]

1：remove some repeat code
2：fix some staticcheck

[tanjunchen]

/cc @justinsb

[johngmyers]

I don't quite see the value of removing the unreferenced convenience functions. I think it would make sense to either consolidate the convenience functions to just the ones in fi or just leave them alone.

[tanjunchen]

@johngmyers Thanks your view.
1:Maybe you can refer to the issue kubernetes/kubernetes#81657
2:And we need to delete unused code because of golang rules(recommend to do this)

[tanjunchen]

@rifelpet The Same Question

[tanjunchen]

/cc @mikesplain

[justinsb]

I'd say if there is a linter that is reliable that we can use, I am in favor of more static analysis to help us in code review. We've started using hack/verify-staticcheck.sh (albeit with a lot of excluded packages right now)

While in general I agree with @johngmyers that if we have two functions i32 and i64, and we stop using i64, then we shouldn't necessarily rush to delete i64. But I do think that having static checkers helping us avoid mistakes is possibly more important. I think @johngmyers raises an excellent point though, in that we could also put these into a helper package. (Unfortunately fi has become a bit big, so we started pkg/values)

So I'm in favor of this PR, in that if we can get hack/verify-staticcheck.sh checking all our code, it should save us a lot of time in code review. I personally think some of the rules are not what I would have chosen, but having a set of rules will save us a lot of time. (It's the same as the gofmt argument: not perfect, but at least we don't have to debate tabs vs spaces)

/approve
/lgtm

[k8s-ci-robot]

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[johngmyers]

/retest