Can a sourceHandler with functions be used with a resolver?

[Mathijne]

Hi! I've the following mesh config with a simple helloworld implementation to illustrate what I try to do:

export const composeConfig = defineConfig({
  subgraphs: [
    {
      sourceHandler: () => ({
        name: 'helloworld',
        schema$: new GraphQLSchema({
          query: new GraphQLObjectType({
            name: 'Query',
            fields: {
              hello: {
                type: GraphQLString,
                resolve: () => 'world',
              },
            },
          }),
        })
      }),
    },
    {
      sourceHandler: loadGraphQLHTTPSubgraph("Countries", {
        endpoint: "https://countries.trevorblades.com",
      }),
    },
  ],
  additionalTypeDefs: /* GraphQL */ `
    extend type Country {
      hello: String
        @resolveTo(
          sourceName: "helloworld"
          sourceTypeName: "Query"
          sourceFieldName: "hello"
          requiredSelectionSet: "{ code }"
          sourceArgs: {  }
        )
    }`,
  output: 'src/generated/supergraph.js'
})

Two questions:

1. Is the helloworld example a valid use of sourceHandler? Using it with query hello { hello } does work, so it does seem so.
2. If it is, should I also be able to use it with the @resolveTo also?

If both are true I probably have to file a bug-report. As the latest query query country_hello { country(code: "NL") { hello }} tries to attach a transport with name "" and fails on it.

Many thanks in advance!

Kind regards,
Mathijn

[ardatan]

You should use the given loaders of Mesh as sourceHandler.

{
  sourceHandler: () => ({
    name: 'helloworld',
    schema$: new GraphQLSchema({
      query: new GraphQLObjectType({
        name: 'Query',
        fields: {
          hello: {
            type: GraphQLString,
            resolve: () => 'world',
          },
        },
      }),
    })
  }),
},