Absinthe Root Query Pagination

schema.ex

defmodule WkGraphql.Schema do
  use Absinthe.Schema
  import_types WkGraphql.Schema.Types

  query do

    @desc "Get a user"
    field :user, :user do
      arg :id, non_null(:integer)
      resolve &WkGraphql.UserResolver.find/2
    end

    @desc "Get all users"
    field :users, list_of(:user) do
        resolve &WkGraphql.UsersResolver.all/2
    end

  
    # field :threads_list, :threads do
    #   resolve &WkGraphql.MessageResolver.find_all_threads/2
    # end
    
    # @desc "Get all message threads"
    # field :threads, list_of(:thread) do
    #   resolve &WkGraphql.MessageResolver.find_all_threads/2
    # end

    connection field :threads, node_type: :thread do
      arg :first, non_null(:integer)
      arg :last, :string
      resolve fn
          p_args, %{source: thread, context: %{uuid: uuid, current_user: user}} ->
            thread_id = get_thread_id(thread)
            with  thread <- Messages.find_all_threads_query(thread, user, uuid),
                  connection <- Absinthe.Relay.Connection.from_query(thread, &WkGraphql.Repo.all/1, p_args) do
                    {:ok, connection}
            else
                {:error, error} -> {:error, error}
                _ -> {:error, "Error fetching Threads"}
            end
        end
  end

    @desc "Find a thread"
    field :thread, :thread do
      arg :thread_id, non_null(:integer)
      resolve &WkGraphql.MessageResolver.find_thread_by_id/2
    end

  end
end

Solved! I have to return Absinthe.Relay.Connection.from_query(thread, &WkGraphql.Repo.all/1, p_args) directly

resolve fn
  p_args, %{source: thread, context: %{uuid: uuid, current_user: user}} ->
    Messages.find_all_threads_query(thread, user, uuid)
    |> Absinthe.Relay.Connection.from_query(&WkGraphql.Repo.all/1, p_args)
end

It is worth noting source: threadis unecessary because you are list the root object. You have to use source when you are listing associated object ( https://hexdocs.pm/absinthe_relay/Absinthe.Relay.Connection.html#module-connection )

object :person do
  field :first_name, :string
  connection field :pets, node_type: :pet do
    resolve fn
      pagination_args, %{source: person} ->
        Absinthe.Relay.Connection.from_list(
          Enum.map(person.pet_ids, &pet_from_id(&1)),
          pagination_args
        )
      end
    end
  end
end