Graphql-tools: Regression with error stitching in v6

[alfaproject]

So, I decided to give a go at updating our stack to use v6 and since I was using a custom lambda link I'll start with @graphql-tools/link module to ease the transition (eventually I want to replace my custom link but for now just wanted to see everything working).

After a few hours of refactoring a few imports and schema transformations, I got everything working EXCEPT errors.

Example of a subschema definition:

import { typeDefs } from '@tma/lambda-auth/modules/typedefs';

const link = split(
  ({ query }) => {
    const definition = getMainDefinition(query);
    return definition.kind === 'OperationDefinition' && definition.operation === 'subscription';
  },
  createLambdaLink('lambda-auth', 'graphqlSubscriptionServer'),
  createLambdaLink('lambda-auth', 'graphqlServer'),
);

export const authSchema = wrapSchema({
  executor: linkToExecutor(link),
  schema: makeExecutableSchema({ typeDefs }),
  subscriber: linkToSubscriber(link),
});

Example of a mutation:

mutation {
  login(input: {
    password: "whatever"
    username: "whatever"
  }) {
    accessToken
  }
}

Example of a RAW successful response from the downstream service (logged from the custom link):

{
  data: {
    login: {
      accessToken: 'eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJleHAiOjE1OTEwMjY4MjUsInNpZCI6IndManpYQ1piZmhrczdHaHZ6OEY4IiwidWlkIjoiMDAwMDAwMDAwMDAwMDAwMDAwMDAwMDAxIn0.G5YFfv3vRL85AcPzmdr8YvavIV1Wpvy-mQu9LUn9Cf0'
    }
  }
}

Example of a RAW error response from the downstream service (logged from the custom link):

{
  errors: [
    {
      message: 'INVALID_CREDENTIALS',
      locations: [Array],
      path: [Array],
      extensions: [Object]
    }
  ],
  data: null
}

This error output leads to this response to the client:

{
  "errors": [
    {
      "message": "Cannot return null for non-nullable field LoginPayload.accessToken.",
      "locations": [
        {
          "line": 3,
          "column": 5
        }
      ],
      "path": [
        "login",
        "accessToken"
      ],
      "extensions": {
        "code": "INTERNAL_SERVER_ERROR",
        "exception": {
          "stacktrace": [
            "Error: Cannot return null for non-nullable field LoginPayload.accessToken.",
            "    at completeValue (/var/task/src/handlers/graphql-server.js:71953:13)",
            "    at completeValueCatchingError (/var/task/src/handlers/graphql-server.js:71888:19)",
            "    at resolveField (/var/task/src/handlers/graphql-server.js:71830:10)",
            "    at executeFields (/var/task/src/handlers/graphql-server.js:71671:18)",
            "    at collectAndExecuteSubfields (/var/task/src/handlers/graphql-server.js:72106:10)",
            "    at completeObjectValue (/var/task/src/handlers/graphql-server.js:72096:10)",
            "    at completeValue (/var/task/src/handlers/graphql-server.js:71984:12)",
            "    at completeValue (/var/task/src/handlers/graphql-server.js:71950:21)",
            "    at /var/task/src/handlers/graphql-server.js:71885:16",
            "    at Promise.propagateAslWrapper (/var/task/src/handlers/graphql-server.js:40168:23)",
            "    at Promise.__asl_wrapper (/var/task/src/handlers/graphql-server.js:39356:31)",
            "    at proxyWrapper (/var/task/src/handlers/graphql-server.js:40193:23)",
            "    at /var/task/src/handlers/graphql-server.js:40205:70",
            "    at /var/task/src/handlers/graphql-server.js:39356:31",
            "    at processTicksAndRejections (internal/process/task_queues.js:97:5)"
          ]
        }
      }
    }
  ],
  "data": null
}

Because there is an error, obviously LoginPayload.accessToken is null, so I'm not sure why it's giving that response... This works as expected with graphql-tools v4

[yaacovCR]

Thanks for reporting! Do you think you could put together a minimally reproducing example with the typedefs, schemas? Thanks!

[alfaproject]

@yaacovCR I've done a PR with a reproduction that should emulate my setup accurately. Let me know if you need anything else or if you can suggest a different way of doing things.

[yaacovCR]

Thanks, awesome, my comment there...

[ardatan]

Available in v6.0.6 !