Error 400 when working with rover graph introspect

[tsibelman]

Description

Created an Apollo express server, was able successfully go to http://localhost:4000 in the browser and expect the schema.
Tried to run "rover graph introspect http://localhost:4000" get back 400 error. If I run rover with debug logger, I see an error like this:

  DEBUG introspector_gadget::blocking::client: {"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 (/Users/michaeltsibelman/repos/docontrol/adam/node_modules/@apollo/server/src/internalErrorClasses.ts:15:5)","    at new BadRequestError (/Users/michaeltsibelman/repos/docontrol/adam/node_modules/@apollo/server/src/internalErrorClasses.ts:116:5)","    at runHttpQuery (/Users/michaeltsibelman/repos/docontrol/adam/node_modules/@apollo/server/src/runHttpQuery.ts:169:15)","    at runPotentiallyBatchedHttpQuery (/Users/michaeltsibelman/repos/docontrol/adam/node_modules/@apollo/server/src/httpBatching.ts:85:30)","    at ApolloServer.executeHTTPGraphQLRequest (/Users/michaeltsibelman/repos/docontrol/adam/node_modules/@apollo/server/src/ApolloServer.ts:1038:50)","    at processTicksAndRejections (node:internal/process/task_queues:96:5)"]}}]}

    at /Users/distiller/.cargo/registry/src/github.com-1ecc6299db9ec823/introspector-gadget-0.2.0/src/blocking/client.rs:133

Steps to reproduce

A minimal repro app

import { expressMiddleware } from '@apollo/server/express4';
import { ApolloServer } from '@apollo/server';
import { buildSubgraphSchema } from '@apollo/subgraph';
import express from 'express';
import http from 'http';
import cors from 'cors';
import { json } from 'body-parser';
import gql from 'graphql-tag';

export const typeDefs = gql`
    """
    Adam entry
    """
    type AdamEntry {
        """
        Name field
        """
        name: String!

        """
        Job field
        """
        job: String!
    }

    """
    Query
    """
    type Query {
        """
        Get entity by status
        """
        get: AdamEntry!
    }
`;

export interface IEntity {
    name: string;
    job: string;    
}

const schema = buildSubgraphSchema({
    typeDefs,
    resolvers: {
        Query: {
            async get(): Promise<IEntity> {                
                return {name:"test", job:"test"};
            },
        }
    }    
});

export const apolloServer = new ApolloServer({
    schema,
    introspection: true,
});

await apolloServer.start();

const app = express();
const httpServer = http.createServer(app);

app.use(
    '/graphql',
    cors<cors.CorsRequest>(),
    json(),
    expressMiddleware(apolloServer),
);

await httpServer.listen({ port: 4000 })
console.log(`🚀 Server ready at http://localhost:4000/graphql`);

Environment

Rover Info:
Version: 0.10.0
Install Location: /Users/michaeltsibelman/repos/docontrol/adam/node_modules/binary-install/node_modules/.bin/rover
OS: Mac OS 13.0.1 [64-bit]
Shell: /bin/zsh

[tsibelman]

I debuged it further looks like you send request with JSON like this
{
"variables": null,
"query": "query GraphIntrospectQuery { __schema { queryType { name } mutationType { name } subscriptionType { name } types { ...FullType } directives { name description locations args { ...InputValue } } }}fragment FullType on __Type { kind name description fields(includeDeprecated: true) { name description args { ...InputValue } type { ...TypeRef } isDeprecated deprecationReason } inputFields { ...InputValue } interfaces { ...TypeRef } enumValues(includeDeprecated: true) { name description isDeprecated deprecationReason } possibleTypes { ...TypeRef }}fragment InputValue on __InputValue { name description type { ...TypeRef } defaultValue}fragment TypeRef on __Type { kind name ofType { kind name ofType { kind name ofType { kind name ofType { kind name ofType { kind name ofType { kind name ofType { kind name } } } } } } }}",
"operationName": "GraphIntrospectQuery"
}

But apollo server v4 is not expecting to get this as a null
https://github.com/apollographql/apollo-server/blob/18501ffeeffe1a7751e841c8c365ba8b277d73ac/packages/server/src/runHttpQuery.ts#L172

Looks like this change was introduced 15 days ago apollographql/apollo-server@37b3b7f and this a regression between rover and server

[EverlastingBugstopper]

Hi @tsibelman - this was a regression in Apollo Server 4.2.0 and was fixed in this PR. If you update to apollo server 4.2.2 this issue should be resolved.