Introspection error because I'm using a type for both input and output

Questions / Help
1

Let’s say I have a basic type called an article

object :article do
    field(:id, :id)
    field(:author, :string)
    field(:body, :string)
  end

I can have a query like this:

query do
  field :articles, list_of(:article) do
     ...
  end
end

But if I did this

mutation do
  field :upload_articles, :boolean do
      arg(:input, non_null(:upload_article_input))
    end
end

input_object :upload_article_input do
  field(:articles, non_null(list_of(:article)))
end

I get this error

Introspection must provide input type for arguments, but received: [Article]!.

My hack around this was to create

input_object :input_article do
    field(:id, :id)
    field(:author, :string)
    field(:body, :string)
end

input_object :upload_article_input do
  field(:articles, non_null(list_of(:input_article)))
end

and use that in the input, but since it’s fundamentally the same as the object :article, is there a better way to do this?

2

This is not a hack, this is the correct way to do it, although by convention the type is usually called article_input instead of input_article. Although in simple examples the inputs and outputs are identical, this always changes as APIs get more complex, and you want to create space for those to evolve separately.

3

Thanks Ben. I’ll go with that. Also I only noticed this when I tried to parse it with a external JS lib get-graphql-schema. Is there anyway to write a test in my code that ensures the introspection isn’t broken?

4

What version of Absinthe are you on? Modern versions of Absinthe should error out at compile time with the schema that you wrote.

5

1.4.16

It runs and compiles fine. Is there a way I can write a test that would fail instead?

6

Hm, it definitely shouldn’t. Absinthe does its best to prevent the creation of illegal schemas at compile time. Can you try it on 1.5.1?