fix: fix index validation for PUT requests

[debug-ing]

fix issues #6822

[CLAassistant]

All committers have signed the CLA.

[mholt]

Thanks. Did you double-check that the PUT logic below is still correct if idx == len(arr)?

case http.MethodPut:
    // avoid creation of new slice and a second copy (see
    // https://github.com/golang/go/wiki/SliceTricks#insert)
    arr = append(arr, nil)
    copy(arr[idx+1:], arr[idx:])
    arr[idx] = val
    v[part] = arr

[debug-ing]

Yes, the PUT logic works correctly when idx == len(arr). It behaves as expected by appending the new element at the end of the array.

[debug-ing]

Hi, the code is all good—every test is passing except this one CI run. It hit a network issue where the self-hosted runner couldn't reach GitHub’s endpoints during the artifact upload.

[mholt]

Yeah, we have some known flaky tests. Thanks!