From 2c807ddbfe5f294bbe75db2b8671bd625499ed8e Mon Sep 17 00:00:00 2001
From: Egor Yurtaev <yurtaev.egor@gmail.com>
Date: Mon, 16 Aug 2021 15:40:26 +0800
Subject: [PATCH] fix(buildOperationNodeForField): mutation response return a
 field of type Query (#3383)

* test: Test for buildOperationNodeForField #3380

* fix(buildOperationNodeForField): mutation response return a field of type Query

* enhance(buildOperationNodeForField): mutation response return a field of type Query

Co-authored-by: Arda TANRIKULU <ardatanrikulu@gmail.com>
---
 .changeset/shaggy-monkeys-smoke.md            |  5 ++
 .../utils/src/build-operation-for-field.ts    | 22 ++++-
 .../build-operation-node-for-field.spec.ts    | 81 +++++++++++++++++++
 3 files changed, 104 insertions(+), 4 deletions(-)
 create mode 100644 .changeset/shaggy-monkeys-smoke.md

diff --git a/.changeset/shaggy-monkeys-smoke.md b/.changeset/shaggy-monkeys-smoke.md
new file mode 100644
index 00000000000..8e77c8097d5
--- /dev/null
+++ b/.changeset/shaggy-monkeys-smoke.md
@@ -0,0 +1,5 @@
+---
+'@graphql-tools/utils': patch
+---
+
+enhance(buildOperationNodeForField): mutation response return a field of type Query
diff --git a/packages/utils/src/build-operation-for-field.ts b/packages/utils/src/build-operation-for-field.ts
index c9f45f1d975..0be498e66a3 100644
--- a/packages/utils/src/build-operation-for-field.ts
+++ b/packages/utils/src/build-operation-for-field.ts
@@ -28,7 +28,7 @@ import {
   Kind,
 } from 'graphql';
 
-import { getDefinedRootType } from './rootTypes';
+import { getDefinedRootType, getRootTypeNames } from './rootTypes';
 
 let operationVariables: VariableDefinitionNode[] = [];
 let fieldTypeMap = new Map();
@@ -60,7 +60,7 @@ export function buildOperationNodeForField({
   kind,
   field,
   models,
-  ignore,
+  ignore = [],
   depthLimit,
   circularReferenceDepth,
   argNames,
@@ -79,16 +79,19 @@ export function buildOperationNodeForField({
   resetOperationVariables();
   resetFieldMap();
 
+  const rootTypeNames = getRootTypeNames(schema);
+
   const operationNode = buildOperationAndCollectVariables({
     schema,
     fieldName: field,
     kind,
     models: models || [],
-    ignore: ignore || [],
+    ignore,
     depthLimit: depthLimit || Infinity,
     circularReferenceDepth: circularReferenceDepth || 1,
     argNames,
     selectedFields,
+    rootTypeNames,
   });
 
   // attach variables
@@ -110,6 +113,7 @@ function buildOperationAndCollectVariables({
   circularReferenceDepth,
   argNames,
   selectedFields,
+  rootTypeNames,
 }: {
   schema: GraphQLSchema;
   fieldName: string;
@@ -120,6 +124,7 @@ function buildOperationAndCollectVariables({
   circularReferenceDepth: number;
   argNames?: string[];
   selectedFields: SelectedFields;
+  rootTypeNames: Set<string>;
 }): OperationDefinitionNode {
   const type = getDefinedRootType(schema, kind);
   const field = type.getFields()[fieldName];
@@ -159,6 +164,7 @@ function buildOperationAndCollectVariables({
           depth: 0,
           argNames,
           selectedFields,
+          rootTypeNames,
         }),
       ],
     },
@@ -179,6 +185,7 @@ function resolveSelectionSet({
   depth,
   argNames,
   selectedFields,
+  rootTypeNames,
 }: {
   parent: GraphQLNamedType;
   type: GraphQLNamedType;
@@ -193,6 +200,7 @@ function resolveSelectionSet({
   depth: number;
   selectedFields: SelectedFields;
   argNames?: string[];
+  rootTypeNames: Set<string>;
 }): SelectionSetNode | void {
   if (typeof selectedFields === 'boolean' && depth > depthLimit) {
     return;
@@ -232,6 +240,7 @@ function resolveSelectionSet({
               depth,
               argNames,
               selectedFields,
+              rootTypeNames,
             }) as SelectionSetNode,
           };
         })
@@ -276,6 +285,7 @@ function resolveSelectionSet({
               depth,
               argNames,
               selectedFields,
+              rootTypeNames,
             }) as SelectionSetNode,
           };
         })
@@ -283,7 +293,7 @@ function resolveSelectionSet({
     };
   }
 
-  if (isObjectType(type)) {
+  if (isObjectType(type) && !rootTypeNames.has(type.name)) {
     const isIgnored = ignore.includes(type.name) || ignore.includes(`${parent.name}.${path[path.length - 1]}`);
     const isModel = models.includes(type.name);
 
@@ -328,6 +338,7 @@ function resolveSelectionSet({
               depth,
               argNames,
               selectedFields: selectedSubFields,
+              rootTypeNames,
             });
           }
           return null;
@@ -403,6 +414,7 @@ function resolveField({
   depth,
   argNames,
   selectedFields,
+  rootTypeNames,
 }: {
   type: GraphQLObjectType;
   field: GraphQLField<any, any>;
@@ -417,6 +429,7 @@ function resolveField({
   depth: number;
   selectedFields: SelectedFields;
   argNames?: string[];
+  rootTypeNames: Set<string>;
 }): SelectionNode {
   const namedType = getNamedType(field.type);
   let args: ArgumentNode[] = [];
@@ -489,6 +502,7 @@ function resolveField({
           depth: depth + 1,
           argNames,
           selectedFields,
+          rootTypeNames,
         }) || undefined,
       arguments: args,
     };
diff --git a/packages/utils/tests/build-operation-node-for-field.spec.ts b/packages/utils/tests/build-operation-node-for-field.spec.ts
index 53e9612e24f..2349867392b 100644
--- a/packages/utils/tests/build-operation-node-for-field.spec.ts
+++ b/packages/utils/tests/build-operation-node-for-field.spec.ts
@@ -260,6 +260,87 @@ test('should work with mutation', async () => {
   );
 });
 
+test('should work with mutation + return a field of type Query', async () => {
+  const schema = buildSchema(/* GraphQL */ `
+    type Pizza {
+      dough: String!
+      toppings: [String!]
+      query: Query
+    }
+
+    type Query {
+      pizza: Pizza
+      pizzaById(id: String!): Pizza
+    }
+    type Mutation {
+      addPizza(name: String!): Pizza
+    }
+  `)
+  const document = buildOperationNodeForField({
+    schema,
+    kind: 'mutation',
+    field: 'addPizza',
+    models,
+    ignore: [],
+  })!;
+
+  expect(clean(document)).toEqual(
+    clean(/* GraphQL */ `
+      mutation addPizza_mutation($name: String!) {
+        addPizza(name: $name) {
+          dough
+          toppings
+        }
+      }
+    `)
+  );
+});
+
+test('should work with mutation + Union + return a field of type Query', async () => {
+  const schema = buildSchema(/* GraphQL */ `
+    type Pizza {
+      dough: String!
+      toppings: [String!]
+      query: Query
+    }
+    type Salad {
+      ingredients: [String!]!
+      query: Query
+    }
+    union Food = Pizza | Salad
+    type Query {
+      pizza: Pizza
+      getPizzaById(id: String!): Pizza
+    }
+    type Mutation {
+      addRandomFood(name: String!): Food
+    }
+  `)
+  const document = buildOperationNodeForField({
+    schema,
+    kind: 'mutation',
+    field: 'addRandomFood',
+    models,
+    ignore: [],
+  })!;
+
+  expect(clean(document)).toEqual(
+    clean(/* GraphQL */ `
+      mutation addRandomFood_mutation($name: String!) {
+        addRandomFood(name: $name) {
+          ... on Pizza {
+            dough
+            toppings
+          }
+          ... on Salad {
+            ingredients
+          }
+        }
+      }
+    `)
+  );
+});
+
 test('should work with mutation and unions', async () => {
   const document = buildOperationNodeForField({
     schema,