Missing nested optional array transformed into hash with declared method

[hyunskang]

grape v1.1.0
ruby v2.4.4

API definition:

params do
    requires :obj, type: Hash, allow_blank: false do
    requires :id, type: Integer, allow_blank: false
    optional :arr, type: Array, allow_blank: true do
      requires :k, type: String, allow_blank: false
      requires :v, type: String, allow_blank: false
    end
  end
end
put '/results' do
  present(declared(params))
end

Request body:

{ 
    "obj": { 
        "id": 1 
    } 
}

Response body:

{
    "obj": {
        "id": 1,
        "arr": {
            "k": null,
            "v": null
        }
    }
}

When nested array is missing from the request, declared transforms it into a Hash with nil values.
I would expect it to return nil or an empty array. It looks like there was an issue opened for it, but the specs written for it do not seem to be testing the issue. #1642

[dblock]

Makes sense, appreciate a PR with additional specs and maybe even a fix? :)

[dnesteryuk]

@kadotami fixed this issue in #2043 🎉