Schema oneOf among integer and string doesn't work with integer in a string ("1234")

[davidjulien]

Hi!

I would like to define a field id as an integer or a string. Thus I write this schema:

  OpenApiSpex.schema(%{
    oneOf: [
      %Schema{type: :integer},
      %Schema{type: :string}
    ]
  })

It works when my data is an integer 1234 or a string "my_id". But it doesn't work when it is an integer inside a string "1234". It triggers this error:

Value does not conform to schema:
Failed to cast value to one of: more than one schemas validate at .../id

I think that the reason is here. In the module Cast.Integer, we convert the value to integer when it is a binary containing an integer. Consequently, the two clauses of my oneOf are valid.

open_api_spex/lib/open_api_spex/cast/integer.ex

Lines 17 to 22 in 531607c

	def cast(%{value: value} = ctx) when is_binary(value) do
	case Integer.parse(value) do
	{value, ""} -> cast(%{ctx | value: value})
	_ -> Cast.error(ctx, {:invalid_type, :integer})
	end
	end

Is there a workaround or can we remove this function clause?

I tried with anyOf instead of oneOf but in that case I have this error:

 ** (Protocol.UndefinedError) protocol Enumerable not implemented for 1234 of type Integer. This protocol is implemented for the following type(s): ...

Thank you

[davidjulien]

Here is a possible workaround:

  defmodule StrictIntegerValidation do
    @moduledoc """
    Ensure that we have really an integer, and not an integer inside a string
    """
    def cast(ctx) do
      if is_integer(ctx.value) do
        {:ok, ctx.value}
      else
        {:error, "Not strictly integer"}
      end
    end
  end

  OpenApiSpex.schema(%{
    oneOf: [
      %Schema{type: :string},
      %Schema{type: :integer, "x-validate": StrictIntegerValidation}
    ]
  })