Graphql-ruby: Relay RangeAdd always returns null for edge

[amozoss]

Thanks in advance for the awesome library.

I upgraded to graphql 1.8.4 and GraphQL::Relay::RangeAdd.new is always returning null.

I inspected the range_add object and it seems to be fine

#<GraphQL::Relay::RangeAdd:0x00007f0d70319bb8 @parent=nil, @connection=#<GraphQL::Relay::Connection @parent=nil @arguments={}>, @edge=#<GraphQL::Relay::Edge (nil => #<Post id: 11, name: "test", created_at: "2018-06-23 14:29:56", updated_at: "2018-06-23 14:29:56">)>>

Here's the relevant code

class Mutations::CreatePost < GraphQL::Schema::RelayClassicMutation
  null true
  field :postEdge, Types::PostType.edge_type, null: false

  argument :name, String, required: true

  def resolve(**inputs)
    range_add = GraphQL::Relay::RangeAdd.new(
      collection: Post.all,
      item: Post.create!(name: inputs[:name]),
      context: context
    )
    {
      postEdge: range_add.edge
    }
  end
end

class Types::MutationType < Types::BaseObject
  field :createPost, mutation: Mutations::CreatePost
end



md5-fe25a0e80b5e1b09029e61021f99c8d0



$ curl 'http://localhost:3000/graphql' \
-d 'query=mutation CreatePost($input: CreatePostInput!) { createPost(input: $input) { postEdge { node { name } } clientMutationId } }' \
-d 'variables={"input": {"name": "test"}}'

{"data":{"createPost":null},"errors":[{"message":"Cannot return null for non-nullable field CreatePostPayload.postEdge"}]}

Any ideas on what could be happening?

[amozoss]

Figured it out, I needed to return post_edge instead of postEdge in my resolve function.

{
  post_edge: range_add.edge
}

A bit confusing, since I defined the field as postEdge.

Side note: postEdge used to work before I moved to the Class-based API.

[amozoss]

Relevant docs

Field and argument names should be underscored as a convention. They will be converted to camelCase in the underlying GraphQL type and be camelCase in the schema itself.

http://graphql-ruby.org/type_definitions/objects.html#object-classes

[rmosolgo]

Glad you found the solution, thanks for following up!