From 63c20097fb28e296066f6654d715456668d91d9c Mon Sep 17 00:00:00 2001
From: Christoph Zwerschke <cito@online.de>
Date: Fri, 6 Mar 2020 14:43:52 +0100
Subject: [PATCH] schema: fix error message when provided type has no name
 (#2475)

Avoid confusing error messages about "multiple types named undefined".
---
 src/type/__tests__/schema-test.js | 13 +++++++++++++
 src/type/schema.js                |  4 ++++
 2 files changed, 17 insertions(+)

diff --git a/src/type/__tests__/schema-test.js b/src/type/__tests__/schema-test.js
index 57dc1d1310..f5f558799b 100644
--- a/src/type/__tests__/schema-test.js
+++ b/src/type/__tests__/schema-test.js
@@ -357,6 +357,19 @@ describe('Type System: Schema', () => {
         );
       });
 
+      it('rejects a Schema when a provided type has no name', () => {
+        const query = new GraphQLObjectType({
+          name: 'Query',
+          fields: { foo: { type: GraphQLString } },
+        });
+        const types = [{}, query, {}];
+
+        // $DisableFlowOnNegativeTest
+        expect(() => new GraphQLSchema({ query, types })).to.throw(
+          'One of the provided types for building the Schema is missing a name.',
+        );
+      });
+
       it('rejects a Schema which defines an object type twice', () => {
         const types = [
           new GraphQLObjectType({ name: 'SameName', fields: {} }),
diff --git a/src/type/schema.js b/src/type/schema.js
index 5cb5241547..2b42870374 100644
--- a/src/type/schema.js
+++ b/src/type/schema.js
@@ -213,6 +213,10 @@ export class GraphQLSchema {
       }
 
       const typeName = namedType.name;
+      devAssert(
+        typeName,
+        'One of the provided types for building the Schema is missing a name.',
+      );
       if (this._typeMap[typeName] !== undefined) {
         throw new Error(
           `Schema must contain uniquely named types but contains multiple types named "${typeName}".`,