A param of type Hash is converted to Array in declared(params)

[arempe93]

Spec describing the issue

it 'declared Hash groups should be a Hash' do

    app.params do
        optional :group, type: Hash do
            optional :foo, type: String
        end
    end
    app.get :group do
        declared(params).to_json
    end

    get '/group'
    json = JSON.parse(last_response.body)

    puts json['group'].class.name
    expect(json['group']).to be_kind_of(Hash)
end

This produces the following output

Array
Failure/Error: expect(json['group']).to be_kind_of(Hash)
       expected [] to be a kind of Hash

Setting a default on the param is a workaround

it 'declared Hash groups should be a Hash' do

    app.params do
        optional :group, type: Hash, default: {} do
            optional :foo, type: String
        end
    end
    app.get :group do
        declared(params).to_json
    end

    get '/group'
    json = JSON.parse(last_response.body)

    puts json['group']
    expect(json['group']).to be_kind_of(Hash)
end

This spec passes without error with the expected output

{ "foo" => nil }

Using Grape v0.14.0, running specs on master

[dblock]

Looks like a definite bug, I would expect group not to be in the response at all without a default, right?

[arempe93]

That could be an expectation, yes. Personally I like having it still be there and showing the values of the nested parameters because of the way I use / think about them as groups. But in either case, I don't think an Array is an expected value

[ochagata]

I believe that this is due to this specific line:

https://github.com/ruby-grape/grape/blob/master/lib/grape/dsl/inside_route.rb#L48

[arempe93]

Is this an intended behavior, as set forth by this spec in specs/grape/endpoint_spec.rb?. This tests pretty much the exact opposite of the spec from the issue description

[dblock]

I think that spec ignores the fact that there's an explicit type.

[dnesteryuk]

@kadotami fixed this issue in #2043 🎆