Federation: unnecessary query

[paneq]

Let's say you have me query which returns type User defined in Accounts service. The current user can have some reviews which are served from Reviews service.

Let's say current user ID is known based on JWT token in an Authorization header.

When asking for:

me {
  reviews
}

the GQL gateway queries accounts service even though the client does not ask for any attributes from it. This seems unnecessary.

QueryPlan {
  Sequence {
    Fetch(service: "accounts") {
      {
        me {
          __typename
        }
      }
    },
    Flatten(path: "me") {
      Fetch(service: "reviews") {
        {
          ... on User {
            __typename
          }
        } =>
        {
          ... on User {
            reviews {
              body
            }
          }
        }
      },
    },
  },
}

The expected behavior would be that only a single query to Reviews service is sent and no query gets sent to the Accounts service.

Checklist for myself

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• The package name and version of Apollo showing the problem.
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• The expected behavior.
• The actual behavior.
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