Grape API malformed parameters

I'm trying to make a post endpoint, with multiple nested parameters but the params are not as expected

I have the following parameters definitions for the endpoint:

params do
  requires :p2 do
    optional :p3
    requires :p4, as: :p4_new
    requires :p5, as: :p5_new do
      requires :p6, as: :p6_new
    end
  end
end

So I put a debugger in the first line of the endpoint and I am expecting the parameters to look like this:

{
  "p2": {
    "p3": 1,
    "p4_new": "Ceva nume",
    "p5_new": {
      "p6_new": 1,
    }
  }
}

But the actual parameters are malformed, it gives me both the newly named parameters and the old name for the parameters, in a chaotic order. It doesn't make any sense. Does anyone know what is going on here?

You're seeing the difference between params and declared(params). The documentation on renaming params specifies that if you want only the renamed parameters that you need to use declared(params):

You can rename parameters using as, which can be useful when refactoring existing APIs:

resource :users do
  params do
    requires :email_address, as: :email
    requires :password
  end
  post do
    User.create!(declared(params)) # User takes email and password
  end
end

The value passed to as will be the key when calling declared(params)

I assume that you're calling params which is giving you both the original and the renamed parameters merged together. Switch to declared(params) to get just the renamed parameters.