v4.2 regression: variables: null (etc) should be allowed

[mabuyo]

Description

When running rover dev on a subgraph using Apollo Server 4, I get error [E004].

Steps to reproduce

1. Clone https://github.com/apollographql-education/lift-off-supergraph-demo-users
2. On the main branch, run npm i and npm start.
3. In another terminal, run rover dev --url http://localhost:4002 --name users.
4. This should work perfectly, can query the router through Sandbox. The main branch uses Apollo Server 3.

Now let's try Apollo Server 4.

1. Stop any running processes from above.
2. Checkout the upgrade/as4 branch.
3. Run npm i and npm start
4. In another terminal, run rover dev --url http://localhost:4002 --name users.

Expected result

Rover dev works correctly, as in the first AS3 example. The local router runs, able to query the router through Sandbox on port 3000.

Actual result

rover dev --url http://localhost:4002 --name users
WARN: could not detect a schema in the current working directory. to watch a schema, pass the `--schema <PATH>` argument
👂 polling http://localhost:4002/ every 1 second
error: could not run `rover graph introspect http://localhost:4002/` or `rover subgraph introspect http://localhost:4002/`
        error[E004]: HTTP status client error (400 Bad Request) for url (http://localhost:4002/)
        Make sure the endpoint is accepting connections and is spelled correctly

Running rover subgraph introspect http://localhost:4002/ gets me:

error[E004]: HTTP status client error (400 Bad Request) for url (http://localhost:4002/)
        Make sure the endpoint is accepting connections and is spelled correctly

Environment

Rover Info:
Version: 0.10.0
Install Location: /Users/michelle-apollo/.rover/bin/rover
OS: Mac OS 11.6.4 [64-bit]
Shell: /bin/zsh

[dane-stevens]

This is the error message when i --log trace the end of the rover introspect <endpoint> command:

{
  "errors": [
    {
      "message": "`variables` in a POST body must be an object if provided.",
      "extensions": {
        "code": "BAD_REQUEST",
        "stacktrace": [
          "BadRequestError: `variables` in a POST body must be an object if provided.",
          "    at new GraphQLErrorWithCode (/home/skyf4ll/Documents/Websites/NAPA/napa-api/node_modules/@apollo/server/src/internalErrorClasses.ts:15:5)",
          "    at new BadRequestError (/home/skyf4ll/Documents/Websites/NAPA/napa-api/node_modules/@apollo/server/src/internalErrorClasses.ts:116:5)",
          "    at runHttpQuery (/home/skyf4ll/Documents/Websites/NAPA/napa-api/node_modules/@apollo/server/src/runHttpQuery.ts:169:15)",
          "    at runPotentiallyBatchedHttpQuery (/home/skyf4ll/Documents/Websites/NAPA/napa-api/node_modules/@apollo/server/src/httpBatching.ts:85:30)",
          "    at ApolloServer.executeHTTPGraphQLRequest (/home/skyf4ll/Documents/Websites/NAPA/napa-api/node_modules/@apollo/server/src/ApolloServer.ts:1038:50)",
          "    at processTicksAndRejections (node:internal/process/task_queues:96:5)"
        ]
      }
    }
  ]
}

[dane-stevens]

The issue seems to be that rover is passing "variables": null in the POST request. Apollo server doesn't like this.

I am able to intercept the POST request through ngrok, then manually change the "variables": null to an empty object (ie. "variables": {} and I get a 200 OK response after that.

[dane-stevens]

This is caused by the 4.2.0 release of @apollo/server: https://github.com/apollographql/apollo-server/releases/tag/%40apollo%2Fserver%404.2.0

[eunchurn]

Please remove variables: null in GraphIntrospectQuery.

[EverlastingBugstopper]

Thanks all for all of the wonderful context on this issue. I'm going to transfer it to the apollo-server repository since this is a regression on the server side. Essentially apollo-server is a bit over-eager to reject requests (it is valid to send variables: null in a GraphQL request).

[glasser]

Right, this was an unintentional regression in v4.2. We added some reasonable type validation in that change but banning variables: null should not have happened (even according to the spec). Going to first improve the spec test suite (graphql/graphql-http#26) and then fix. Thanks all.