Issue with mergeSchemas from graphql-tools v4 to v10

[inPhoenix]

Hello,

I'm currently upgrading graphql-tools from an older version (v4.0) to the latest version (v10.0), and I'm encountering issues with mergeSchemas.

Here's the section of code where the issue arises:

  return mergeSchemas({
    schemas: [executableSchema1, executableSchema2], 
    resolvers: {},
  });

In version 4.0, mergeSchemas properly combined executableSchema1 and executableSchema2, as shown in this screenshot:

However, in version 10.0, it appears that the last schema in the array overwrites the others instead of merging.
I'm pretty sure I'm missing something with the new API, but I haven't been able to find what could be wrong in the
Migration guide or in the docs.

Any guidance that could assist with the upgrade of graphql-tools would be much appreciated.

Here is the full code:

import fetch from "node-fetch";
import { HttpLink } from "apollo-link-http";
import { ApolloServer } from "@apollo/server";
import { startStandaloneServer } from "@apollo/server/standalone";
import {
  introspectSchema,
  makeRemoteExecutableSchema,
  // mergeSchemas, // this version works
} from "graphql-tools"; // graphql-tools ^2.9.7
import { mergeSchemas } from "@graphql-tools/schema"; // graphql-tools ^10.0.0

async function mergedSchema() {
  const starwars = "https://swapi-graphql.netlify.app/.netlify/functions/index";
  const rickandmorty = "https://rickandmortyapi.com/graphql";

  const httpLink1 = new HttpLink({
    uri: starwars,
    fetch,
  });
  const httpLink2 = new HttpLink({
    uri: rickandmorty,
    fetch,
  });

  const schema1 = await introspectSchema(httpLink1);
  const schema2 = await introspectSchema(httpLink2);

  const executableSchema1 = makeRemoteExecutableSchema({
    schema: schema1,
    link: httpLink1,
  });

  const executableSchema2 = makeRemoteExecutableSchema({
    schema: schema2,
    link: httpLink2,
  });

  return mergeSchemas({
    // the latest version overwrites the previous one
    schemas: [executableSchema1, executableSchema2],
    resolvers: {},
  });
}

const runServer = async () => {
  const server = new ApolloServer({
    schema: await mergedSchema(),
    typeDefs: {},
  });

  const { url } = await startStandaloneServer(server, {
    listen: { port: 4000 },
  });
  console.log(`🚀  Server ready at ${url}`);
};

try {
  runServer();
} catch (error) {
  console.error(error);
}

[inPhoenix]

I migrated to the latest version of graphql-tools, but the issue remains unchanged. So I opened an issue with updated code at: #5395

[ardatan]

Closing this discussion because there is already an issue you created.