Allow defaultMergedResolver to resolve renamed field result

CHANGELOG.md

@@ -21,6 +21,9 @@
   [@mfix22](https://github.com/mfix22) in [#983](https://github.com/apollographql/graphql-tools/pull/983)
 * Use `TArgs` generic wherever `IFieldResolver` is used.  <br/>
   [@brikou](https://github.com/brikou) in [#955](https://github.com/apollographql/graphql-tools/pull/955)
+* Resolve original AST field name in `getResponseKeyFromInfo` for [#997] <br/>
+  [@kommander](https://github.com/kommander) in [#1036]
+  (https://github.com/apollographql/graphql-tools/pull/1036)
 * Include deprecations from string SDL in mergeSchemas.  <br/>
   [@evans](https://github.com/evans) in [#1041](https://github.com/apollographql/graphql-tools/pull/1041)
 

src/stitching/getResponseKeyFromInfo.ts

@@ -1,10 +1,15 @@
 import { GraphQLResolveInfo } from 'graphql';
 
 /**
- * Get the key under which the result of this resolver will be placed in the response JSON. Basically, just
- * resolves aliases.
+ * Get the key under which the result of this resolver will be placed in the response JSON.
+ * Resolves aliases and tries to get the original AST name for the field, in case it was renamed.
  * @param info The info argument to the resolver.
  */
 export function getResponseKeyFromInfo(info: GraphQLResolveInfo) {
-  return info.fieldNodes[0].alias ? info.fieldNodes[0].alias.value : info.fieldName;
+  let fieldName = info.fieldNodes[0].alias ? info.fieldNodes[0].alias.value : info.fieldName;
+  const field = info.parentType.getFields()[fieldName];
+  if (field && field.astNode) {
+    fieldName = field.astNode.name.value;
+  }
+  return fieldName;
 }

src/test/testTransforms.ts

@@ -1,6 +1,7 @@
 /* tslint:disable:no-unused-expression */
 
 import { expect } from 'chai';
+import { forAwaitEach } from 'iterall';
 import {
   GraphQLSchema,
   GraphQLNamedType,
@@ -9,9 +10,17 @@ import {
   SelectionSetNode,
   print,
   parse,
+  ExecutionResult,
+  subscribe,
 } from 'graphql';
 import { makeExecutableSchema } from '../makeExecutableSchema';
-import { propertySchema, bookingSchema } from './testingSchemas';
+import {
+  propertySchema,
+  bookingSchema,
+  subscriptionSchema,
+  subscriptionPubSubTrigger,
+  subscriptionPubSub,
+} from './testingSchemas';
 import delegateToSchema from '../stitching/delegateToSchema';
 import {
   transformSchema,
@@ -21,6 +30,7 @@ import {
   ExtractField,
   ReplaceFieldWithFragment,
   FilterToSchema,
+  RenameRootFields,
 } from '../transforms';
 
 describe('transforms', () => {
@@ -86,6 +96,46 @@ describe('transforms', () => {
     });
   });
 
+  describe('rename root fields for subscriptions', () => {
+    let schema: GraphQLSchema;
+    before(() => {
+      const transforms = [
+        new RenameRootFields((_operation: string, name: string) => `prefix_${name}`),
+      ];
+      schema = transformSchema(subscriptionSchema, transforms);
+    });
+    it('should work', done => {
+      const mockNotification = {
+        notifications: {
+          text: 'Hello world',
+        },
+      };
+
+      const subscription = parse(`
+        subscription Subscription {
+          prefix_notifications {
+            text
+          }
+        }
+      `);
+
+      let notificationCnt = 0;
+      subscribe(schema, subscription).then(results =>
+        forAwaitEach(results as AsyncIterable<ExecutionResult>, (result: ExecutionResult) => {
+          expect(result).to.have.property('data');
+          expect(result.data).to.deep.equal({
+            prefix_notifications: {
+              text: 'Hello world',
+            },
+          });
+          !notificationCnt++ ? done() : null;
+        }),
+      );
+
+      subscriptionPubSub.publish(subscriptionPubSubTrigger, mockNotification);
+    });
+  });
+
   describe('namespace', () => {
     let schema: GraphQLSchema;
     before(() => {