Removes flattening of Errors inside of formatApolloErrors (#1288)

* remove unnesting of errors to support yup

* add test for error thrown by yup

packages/apollo-server-errors/src/index.ts

@@ -222,30 +222,27 @@ export function formatApolloErrors(
   }
   const { formatter, debug } = options;
 
-  const flattenedErrors: Error[] = [];
-  errors.forEach(error => {
-    // Errors that occur in graphql-tools can contain an errors array that contains the errors thrown in a merged schema
-    // https://github.com/apollographql/graphql-tools/blob/3d53986ca/src/stitching/errors.ts#L104-L107
-    //
-    // They are are wrapped in an extra GraphQL error
-    // https://github.com/apollographql/graphql-tools/blob/3d53986ca/src/stitching/errors.ts#L109-L113
-    // which calls:
-    // https://github.com/graphql/graphql-js/blob/0a30b62964/src/error/locatedError.js#L18-L37
-    if (Array.isArray((error as any).errors)) {
-      (error as any).errors.forEach(e => flattenedErrors.push(e));
-    } else if (
-      (error as any).originalError &&
-      Array.isArray((error as any).originalError.errors)
-    ) {
-      (error as any).originalError.errors.forEach(e => flattenedErrors.push(e));
-    } else {
-      flattenedErrors.push(error);
-    }
-  });
+  // Errors that occur in graphql-tools can contain an errors array that contains the errors thrown in a merged schema
+  // https://github.com/apollographql/graphql-tools/blob/3d53986ca/src/stitching/errors.ts#L104-L107
+  //
+  // They are are wrapped in an extra GraphQL error
+  // https://github.com/apollographql/graphql-tools/blob/3d53986ca/src/stitching/errors.ts#L109-L113
+  // which calls:
+  // https://github.com/graphql/graphql-js/blob/0a30b62964/src/error/locatedError.js#L18-L37
+  // Some processing for these nested errors could be done here:
+  //
+  // if (Array.isArray((error as any).errors)) {
+  //   (error as any).errors.forEach(e => flattenedErrors.push(e));
+  // } else if (
+  //   (error as any).originalError &&
+  //   Array.isArray((error as any).originalError.errors)
+  // ) {
+  //   (error as any).originalError.errors.forEach(e => flattenedErrors.push(e));
+  // } else {
+  //   flattenedErrors.push(error);
+  // }
 
-  const enrichedErrors = flattenedErrors.map(error =>
-    enrichError(error, debug),
-  );
+  const enrichedErrors = errors.map(error => enrichError(error, debug));
 
   if (!formatter) {
     return enrichedErrors;

packages/apollo-server-integration-testsuite/package.json

@@ -39,7 +39,8 @@
     "graphql-tag": "^2.9.2",
     "js-sha256": "^0.9.0",
     "subscriptions-transport-ws": "^0.9.11",
-    "ws": "^5.2.0"
+    "ws": "^5.2.0",
+    "yup": "^0.25.1"
   },
   "typings": "dist/index.d.ts",
   "typescript": {

packages/apollo-server-integration-testsuite/src/ApolloServer.ts

@@ -7,6 +7,7 @@ import 'mocha';
 import { sha256 } from 'js-sha256';
 import express = require('express');
 import bodyParser = require('body-parser');
+import yup = require('yup');
 
 import { Trace } from 'apollo-engine-reporting-protobuf';
 
@@ -33,6 +34,7 @@ import {
 import { createApolloFetch } from 'apollo-fetch';
 import {
   AuthenticationError,
+  UserInputError,
   gql,
   Config,
   ApolloServerBase,
@@ -345,6 +347,61 @@ export function testApolloServer<AS extends ApolloServerBase>(
         expect(formatError.calledTwice).true;
         expect(throwError.calledTwice).true;
       });
+
+      it('works with errors similar to GraphQL errors, such as yup', async () => {
+        const throwError = stub().callsFake(async () => {
+          const schema = yup.object().shape({
+            email: yup
+              .string()
+              .email()
+              .required('Please enter your email address'),
+          });
+
+          await schema.validate({ email: 'lol' });
+        });
+
+        const formatError = stub().callsFake(error => {
+          expect(error instanceof Error).true;
+          expect(error.extensions.code).to.equal('INTERNAL_SERVER_ERROR');
+          expect(error.extensions.exception.name).to.equal('ValidationError');
+          expect(error.extensions.exception.message).to.exist;
+          const inputError = new UserInputError('User Input Error');
+          return {
+            message: inputError.message,
+            extensions: inputError.extensions,
+          };
+        });
+
+        const { url: uri } = await createApolloServer({
+          typeDefs: gql`
+            type Query {
+              error: String
+            }
+          `,
+          resolvers: {
+            Query: {
+              error: () => {
+                return throwError();
+              },
+            },
+          },
+          introspection: true,
+          debug: true,
+          formatError,
+        });
+
+        const apolloFetch = createApolloFetch({ uri });
+
+        const result = await apolloFetch({
+          query: '{error}',
+        });
+        expect(result.data).to.deep.equal({ error: null });
+        expect(result.errors, 'errors should exist').to.exist;
+        expect(result.errors[0].extensions.code).equals('BAD_USER_INPUT');
+        expect(result.errors[0].message).equals('User Input Error');
+        expect(formatError.calledOnce).true;
+        expect(throwError.calledOnce).true;
+      });
     });
 
     describe('lifecycle', () => {