Cannot read properties of undefined (reading 'args') when schema has a custom directive with argument

[arbejd]

Hi! Thank you for a nice package!

I was adding a custom directive with an argument to my apollo server but validation seems mistake this for one of the @constraint directives.

Reproduction files at the bottom. TLDR: Add a QUERY directive with an argument and try to pass that.

{
"data": {},
"errors": [
  {
    "message": "Cannot read properties of undefined (reading 'args')",
    "extensions": {
      "code": "INTERNAL_SERVER_ERROR",
      "exception": {
        "stacktrace": [
          "TypeError: Cannot read properties of undefined (reading 'args')",
          "    at QueryValidationVisitor.onArgumentEnter ( (...) /node_modules/graphql-constraint-directive/lib/query-validation-visitor.js:118:46)",
          "    at Object.enter ((...) //node_modules/graphql/utilities/TypeInfo.js:391:27)",
          "    at visit ((...) /node_modules/graphql/language/visitor.js:197:21)",
          "    at validateQuery ((...) /node_modules/graphql-constraint-directive/index.js:193:3)",
          "    at Object.didResolveOperation ((...) /node_modules/graphql-constraint-directive/index.js:207:26)",
          "    at /(...) /node_modules/apollo-server-core/dist/utils/dispatcher.js:12:31",
          "    at Array.map (<anonymous>)",
          "    at Dispatcher.callTargets ((...) /apollo-server-core/dist/utils/dispatcher.js:9:29)",
          "    at Dispatcher.invokeHook ((...) /node_modules/apollo-server-core/dist/utils/dispatcher.js:20:33)",
          "    at processGraphQLRequest ((...) /node_modules/apollo-server-core/dist/requestPipeline.js:116:26)"
        ]
      }
    }
  }
]
} 

Reproduction

index.ts

import { ApolloServer } from "apollo-server-express";
import express from "express";
import { makeExecutableSchema } from "@graphql-tools/schema";
import {
  constraintDirectiveTypeDefs,
  createApolloQueryValidationPlugin,
} from "graphql-constraint-directive";



const typeDefs = `#graphql
directive @component(name: String!) on QUERY
type Query {
  getName: String!
}
`;

const schema = makeExecutableSchema({
  typeDefs: [typeDefs, constraintDirectiveTypeDefs],
});

const resolvers = {
  Query: {
    getName: (a,b,c,d) => {return d.operation.directives[0].arguments[0].value.value},
  },
};

const plugins = [createApolloQueryValidationPlugin({ schema })];

const server = new ApolloServer({
  typeDefs: schema,
  resolvers,
  plugins
});


const startServer = async () => {
  await server.start();
  const app = express();
  server.applyMiddleware({ app });
  app.listen({ port: 4000 }, () =>
    console.log(`🚀 Server ready at http://localhost:4000${server.graphqlPath}`)
  );
};

startServer();

package.json

{
"name": "graphql-server-example",
"version": "1.0.0",
"description": "",
"main": "index.js",
"scripts": {
  "compile": "tsc",
  "start": "npm run compile && node ./dist/index.js",
  "test": "echo \"Error: no test specified\" && exit 1"
},
"keywords": [],
"author": "",
"license": "ISC",
"type": "module",
"dependencies": {
  "@apollo/server": "^4.10.0",
  "@graphql-tools/schema": "^10.0.2",
  "apollo-server-express": "^3.13.0",
  "express": "^4.18.2",
  "graphql": "^16.8.1",
  "graphql-constraint-directive": "^5.4.1"
},
"devDependencies": {
  "@types/node": "^20.11.19",
  "typescript": "^5.3.3"
}
}

[simonfaltum]

This PR solves the problem.
#223

The problem was that in these cases this.currentrFieldDef would be undefined. As we just return the function anyway if nothing is found, it makes sense to just add the optional chaining operator.