Including `id` field in query aborts "only" optimization

[maarcingebala]

In my API I have a type which is based on Django's model using DjangoObjectType and relay.Node interface. Using the latter automatically adds the id (graphene.ID) field in the type.

class Product(DjangoObjectType):
    name = graphene.String()

    class Meta:
        interfaces = [relay.Node]
        model = models.Product

Now, when I query the API (with optimizer enabled) and include the id field in the query, the "only optimization" is aborted as a result of this check - my automatically added id field has no name. As a result, this function is called which sets the only_list to None and disables any future "only optimizations" I'd have in my case.

@tfoxy Could you validate the issue? Maybe I broke something on my side, but maybe it is a bug in the library.

Also, I don't fully understand why do you abort the optimization and set None to the only_list. I experimented with the code and assigned [] instead of None in that function and it solved the issue.

[tfoxy]

Can you tell me the python and django version that you are using?

Whenever there is a field that cannot be optimized, the only optimization is removed because maybe there are some fields that are gonna be requested and if the only optimization avoids this fields, the performance will be worse: with only it will do n + 1 queries and without only it will do only 1 query (at the expense of requesting unneeded fields).

[maarcingebala]

I'm running my project on:

• Django version 2.0.8
• Python 3.7.0

[tfoxy]

I cannot reproduce the issue. The method _is_resolver_for_id_field is supposed to get the id name from the resolver. Can you check the type of resolver that the id field has?

[maarcingebala]

Okay, I think I understand much better how the optimization works under the hood and it makes sense to abort the "only" optimization in some cases.

[tfoxy]

Maybe there can be an option to enable or disable that feature.

[yardensachs]

@maarcingebala @tfoxy I submitted PR for this suggestion #15