createEncapsulateTransform ignores types that implement an interface

[fauna5]

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• 1. The issue provides a reproduction available on
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Please make sure Mesh package versions under package.json matches yours.

• 2. A failing test has been provided
• 3. A local solution has been provided
• 4. A pull request is pending review

---

Describe the bug

When using createEncapsulateTransform and a type that implements an interface, the type is not included in the supergraph schema at all. Queries on __typename return the interface and it is not possible to query ... on <type>. After removing the createEncapsulateTransform the mesh behaves as expected.

To Reproduce Steps to reproduce the behavior:

See: https://github.com/fauna5/hive-gateway-playground/tree/encapsulate_issues?tab=readme-ov-file#graphql-mesh-bug-recreation-missing-types-when-using-createencapsulatetransform for an example recreation. The subgraph schema is:

interface Greeting {
  message: String!
}

type HelloGreeting implements Greeting {
  message: String!
  iconName: String!
}

type Query {
  hello: Greeting
}

Expected behavior

After running mesh-compose and hive-gateway querying for

query Test{
  api {
    hello {
      message
      __typename
    }
  }
}

should return

{
  "data": {
    "api": {
      "hello": {
        "message": "Hello world!",
        "__typename": "HelloGreeting"
      }
    }
  }
}

however it returns

{
  "data": {
    "api": {
      "hello": {
        "message": "Hello world!",
        "__typename": "Greeting"
      }
    }
  }
}

...and querying for:

query Test{
  api {
    hello {
      message
      __typename
      ... on HelloGreeting {
         iconName
      }
    }
  }
}

is an invalid query.

Environment:

• OS: OSX
• @graphql-mesh/compose-cli: 1.3.10
• @graphql-hive/gateway: 1.9.4
• NodeJS: 22

Additional context

This works fine when removing the createEncapsulateTransform and adjusting the queries.

I'm trying to separate all my subgraphs under it's their own nodes to avoid schema clashes and can't think of any way to do this without the encapsulation transform.