Reproduction test case

packages/batch-delegate/tests/errorPaths.test.ts

@@ -0,0 +1,153 @@
+import { graphql, GraphQLError } from 'graphql';
+import { batchDelegateToSchema } from '@graphql-tools/batch-delegate';
+import { delegateToSchema } from '@graphql-tools/delegate';
+import { makeExecutableSchema } from '@graphql-tools/schema';
+import { stitchSchemas } from '@graphql-tools/stitch';
+
+class NotFoundError extends GraphQLError {
+  constructor(id: unknown) {
+    super('Not Found', undefined, undefined, undefined, undefined, undefined, { id });
+  }
+}
+
+describe('preserves error path indices', () => {
+  const getProperty = jest.fn((id: unknown) => {
+    return new NotFoundError(id);
+  });
+
+  beforeEach(() => {
+    getProperty.mockClear();
+  });
+
+  const subschema = makeExecutableSchema({
+    typeDefs: /* GraphQL */ `
+      type Property {
+        id: ID!
+      }
+
+      type Object {
+        id: ID!
+        propertyId: ID!
+      }
+
+      type Query {
+        objects: [Object!]!
+        propertyById(id: ID!): Property
+        propertiesByIds(ids: [ID!]!): [Property]!
+      }
+    `,
+    resolvers: {
+      Query: {
+        objects: () => {
+          return [
+            { id: '1', propertyId: '1' },
+            { id: '2', propertyId: '1' },
+          ];
+        },
+        propertyById: (_, args) => getProperty(args.id),
+        propertiesByIds: (_, args) => args.ids.map(getProperty),
+      },
+    },
+  });
+
+  const subschemas = [subschema];
+  const typeDefs = /* GraphQL */ `
+    extend type Object {
+      property: Property
+    }
+  `;
+
+  const query = /* GraphQL */ `
+    query {
+      objects {
+        id
+        property {
+          id
+        }
+      }
+    }
+  `;
+
+  const expected = {
+    errors: [
+      {
+        message: 'Not Found',
+        extensions: { id: '1' },
+        path: ['objects', 0, 'property'],
+      },
+      {
+        message: 'Not Found',
+        extensions: { id: '1' },
+        path: ['objects', 1, 'property'],
+      },
+    ],
+    data: {
+      objects: [
+        {
+          id: '1',
+          property: null as null,
+        },
+        {
+          id: '2',
+          property: null as null,
+        },
+      ],
+    },
+  };
+
+  test('using delegateToSchema', async () => {
+    const schema = stitchSchemas({
+      subschemas,
+      typeDefs,
+      resolvers: {
+        Object: {
+          property: {
+            selectionSet: '{ propertyId }',
+            resolve: (source, _, context, info) => {
+              return delegateToSchema({
+                schema: subschema,
+                fieldName: 'propertyById',
+                args: { id: source.propertyId },
+                context,
+                info,
+              });
+            },
+          },
+        },
+      },
+    });
+
+    const result = await graphql(schema, query);
+
+    expect(getProperty).toBeCalledTimes(2);
+    expect(result).toMatchObject(expected);
+  });
+
+  test('using batchDelegateToSchema', async () => {
+    const schema = stitchSchemas({
+      subschemas,
+      typeDefs,
+      resolvers: {
+        Object: {
+          property: {
+            selectionSet: '{ propertyId }',
+            resolve: (source, _, context, info) => {
+              return batchDelegateToSchema({
+                schema: subschema,
+                fieldName: 'propertiesByIds',
+                key: source.propertyId,
+                context,
+                info,
+              });
+            },
+          },
+        },
+      },
+    });
+
+    const result = await graphql(schema, query);
+
+    expect(getProperty).toBeCalledTimes(1);
+    expect(result).toMatchObject(expected);
+  });
+});