Absinthe Dataloader fetches assocs even if already preloaded

Questions / Help
1

Say the Absinthe resolver returns a struct with an assoc that has already been loaded, e.g.

%Organization{
  name: "Acme",
  members: []
}

When using Dataloader with Absinthe to load the :members for the organization, dataloader will still execute a query to fetch the members while it was already loaded (set to []).

I found this old merge:

But the above GH comments don’t really state why we ignore already preloaded associations. It only mentions consistency but I do not see why we need to execute preload queries again if those had already been executed against the db, leading to double db requests.

Any idea as to why?

2

An example how you can sort it out:

    field :members, non_null(list_of(non_null(:member_type))) do
      resolve(fn parent, args, context ->
        case parent.members do
          %Ecto.Association.NotLoaded{} ->
            dataloader(:source, :members).(parent, args, context)

          members->
            {:ok, members}
        end
      end)
    end
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