Golangci-lint: update scopelint with looppointer or exportloopref

[agnivade]

Hi there,

I am totally aware that the project is going through some rough times. So there's no pressure to work on this right now. Nevertheless, I wanted to file this to just to keep a record.

The author of scopelint has deprecated it for other better linters: https://github.com/kyoh86/scopelint#obsoleted.

Let's use either of them to remain up to date.

Thanks for all the work.

[ernado]

Should we just add both looppointer and exportloopref?

[agnivade]

I think so. Let the user choose what they want. And document it adequately mentioning which is to be used when.

[tamalsaha]

If you want to find lints as nervous as possible (with some false-positives), you should use looppointer.

If you want to find lints as accurately as possible (with some lints ignored), you should use exportloopref.

If you are going to include only one, please include exportloopref. No body wants false positives from their linter.

[sayboras]

Agreed with comment from @tamalsaha above, maybe _exportloopref_ is good enough :)

[kyoh86]

looppointer can be an option.
Maybe this is not so important, but I'd like to mention it.

Since exportloopref cannot find some diagnostics like below.

Case 1: pass the pointer to the function to export.

Case 2: pass the pointer to the local variable, and export it.

package main

type List []*int

func (l *List) AppendP(p *int) {
    *l = append(*l, p)
}

func main() {
    var slice []*int
    list := List{}

    println("loop expect exporting 10, 11, 12, 13")
    for _, v := range []int{10, 11, 12, 13} {
        list.AppendP(&v) // Case 1: wanted "exporting a pointer for the loop variable v", but cannot be found

        p := &v                  // p is the local variable
        slice = append(slice, p) // Case 2: wanted "exporting a pointer for the loop variable v", but cannot be found
    }

    println(`slice expecting "10, 11, 12, 13" but "13, 13, 13, 13"`)
    for _, p := range slice {
        printp(p)
    }
    println(`array expecting "10, 11, 12, 13" but "13, 13, 13, 13"`)
    for _, p := range ([]*int)(list) {
        printp(p)
    }
}

func printp(p *int) {
    println(*p)
}

So we may use looppointer instead of exportloopref if we want to find them all (with some false-positives).

https://github.com/kyoh86/exportloopref#known-false-negatives