Federation not fetching downstream simple query result type Int

[tomi-bigpi]

I ran into an issue with a federated query that simply returns an Int. Calling the service directly (also running on Mercurius) returns the value as expected.

Relevant bit from the schema:

type Query {
  myCount: Int!
}

I'm not seeing any calls from the federation service to the downstream service, and calls fail with Cannot return null for non-nullable field Query.myCount.. Making the return type nullable causes a null to be returned.

Wrapping the result in a custom type, such as type MyAggregations { count: Int! } works as expected.

[mcollina]

This is a tough bug that'll need to solve. Unfortunately it would take a while - my schedule is packed for the next couple of months.

If you would like to take a stab and fix it, it would be awesome:

[codeflyer]

I've created a test file for this issue: #43

It seems to work properly.

[MrSaints]

I know there's a test for it, but this still seems to be an issue when used with Python's Graphene Federation. It works fine using Apollo Federation / Gateway. Tested with both Int! and String! scalar types as the return on the root Query. It is fine if we use a custom type / object type.

EDIT: Issue is resolved when using extend type Query . Related to #23