Problem with federation

[ramiel]

Describe the Bug
I have a problem using type-graphql and federation (with any federation server). I created a small reproduction repository. Basically I think the main problem is that __resolveReference function is never called even if the request is correctly routed to the correct subgraph

To Reproduce
Clone and run https://github.com/ramiel/typegrapqhl-federation-issue
Read the readme file for a detailed explanation.

Expected Behavior
Code should work as the example provided by you

Environment (please complete the following information):

• OS: MacOS
• Node 16
• Package version 2.0.0-beta
• TypeScript version 4.8

[ramiel]

I find out the problem is actually present also in your example/apollo-federation code. To show it you can run the query

query Me {
  me {
    reviews {
      product {
        name
      }
    }
  }
}

This shows the federation is actually not working. @MichalLytek can we move this to issues instead of a discussion?

[ramiel]

The error is present with the example query as well: https://github.com/MichalLytek/type-graphql/blob/new-major-release/examples/apollo-federation/examples.graphql

[MichalLytek]

@ramiel __resolveReference is not a part for TypeGraphQL. It's defined by user and it's his own responsibility to build the apollo schema.

The problem is that with old apollo federation and buildApolloFederationSchema, we could add reference resolvers after building the schema, and it was working well. Now with buildSubgraphSchema it expects reference resolvers to be already provided with the schema.
So we have to merge TypeGraphQL resolvers with reference resolvers somehow. My approach is like this:

import deepMerge from "lodash.merge";

const federatedSchema = buildSubgraphSchema({
  typeDefs: gql(printSchemaWithDirectives(schema)),
  resolvers: deepMerge(createResolversMap(schema) as any, referenceResolvers),
});

I will update the example with this, thanks for noticing the issue.

[ramiel]

Thank you for the reply. I'm going to try this. Understanding all the differences between federation v1 and v2 is a pain 😄