sub-fields on a mutation operation will now process synchronously

Author: Azerothian

src/execution/__tests__/mutations-test.js

@@ -58,6 +58,40 @@ const numberHolderType = new GraphQLObjectType({
   },
   name: 'NumberHolder',
 });
+const subFieldType = new GraphQLObjectType({
+  name: 'subFieldMutation',
+  fields: {
+    immediatelyChangeTheNumber: {
+      type: numberHolderType,
+      args: { newNumber: { type: GraphQLInt } },
+      resolve(obj, { newNumber }) {
+        return obj.immediatelyChangeTheNumber(newNumber);
+      },
+    },
+    promiseToChangeTheNumber: {
+      type: numberHolderType,
+      args: { newNumber: { type: GraphQLInt } },
+      resolve(obj, { newNumber }) {
+        return obj.promiseToChangeTheNumber(newNumber);
+      },
+    },
+    failToChangeTheNumber: {
+      type: numberHolderType,
+      args: { newNumber: { type: GraphQLInt } },
+      resolve(obj, { newNumber }) {
+        return obj.failToChangeTheNumber(newNumber);
+      },
+    },
+    promiseAndFailToChangeTheNumber: {
+      type: numberHolderType,
+      args: { newNumber: { type: GraphQLInt } },
+      resolve(obj, { newNumber }) {
+        return obj.promiseAndFailToChangeTheNumber(newNumber);
+      },
+    },
+  },
+});
+
 const schema = new GraphQLSchema({
   query: new GraphQLObjectType({
     fields: {
@@ -67,6 +101,12 @@ const schema = new GraphQLSchema({
   }),
   mutation: new GraphQLObjectType({
     fields: {
+      subField: {
+        type: subFieldType,
+        resolve(obj) {
+          return obj;
+        },
+      },
       immediatelyChangeTheNumber: {
         type: numberHolderType,
         args: { newNumber: { type: GraphQLInt } },
@@ -118,6 +158,23 @@ describe('Execute: Handles mutation execution ordering', () => {
       fifth: immediatelyChangeTheNumber(newNumber: 5) {
         theNumber
       }
+      subField {
+        first: immediatelyChangeTheNumber(newNumber: 6) {
+          theNumber
+        },
+        second: promiseToChangeTheNumber(newNumber: 7) {
+          theNumber
+        },
+        third: immediatelyChangeTheNumber(newNumber: 8) {
+          theNumber
+        }
+        fourth: promiseToChangeTheNumber(newNumber: 9) {
+          theNumber
+        },
+        fifth: immediatelyChangeTheNumber(newNumber: 10) {
+          theNumber
+        }
+      }
     }`;
 
     const mutationResult = await execute(schema, parse(doc), new Root(6));
@@ -129,6 +186,13 @@ describe('Execute: Handles mutation execution ordering', () => {
         third: { theNumber: 3 },
         fourth: { theNumber: 4 },
         fifth: { theNumber: 5 },
+        subField: {
+          first: { theNumber: 6 },
+          second: { theNumber: 7 },
+          third: { theNumber: 8 },
+          fourth: { theNumber: 9 },
+          fifth: { theNumber: 10 },
+        },
       },
     });
   });
@@ -153,6 +217,26 @@ describe('Execute: Handles mutation execution ordering', () => {
       sixth: promiseAndFailToChangeTheNumber(newNumber: 6) {
         theNumber
       }
+      subField {
+        first: immediatelyChangeTheNumber(newNumber: 7) {
+          theNumber
+        },
+        second: promiseToChangeTheNumber(newNumber: 8) {
+          theNumber
+        },
+        third: failToChangeTheNumber(newNumber: 9) {
+          theNumber
+        }
+        fourth: promiseToChangeTheNumber(newNumber: 10) {
+          theNumber
+        },
+        fifth: immediatelyChangeTheNumber(newNumber: 11) {
+          theNumber
+        }
+        sixth: promiseAndFailToChangeTheNumber(newNumber: 12) {
+          theNumber
+        }
+      }
     }`;
 
     const result = await execute(schema, parse(doc), new Root(6));
@@ -165,6 +249,14 @@ describe('Execute: Handles mutation execution ordering', () => {
         fourth: { theNumber: 4 },
         fifth: { theNumber: 5 },
         sixth: null,
+        subField: {
+          first: { theNumber: 7 },
+          second: { theNumber: 8 },
+          third: null,
+          fourth: { theNumber: 10 },
+          fifth: { theNumber: 11 },
+          sixth: null,
+        },
       },
       errors: [
         {
@@ -177,6 +269,16 @@ describe('Execute: Handles mutation execution ordering', () => {
           locations: [{ line: 17, column: 7 }],
           path: ['sixth'],
         },
+        {
+          message: 'Cannot change the number',
+          locations: [{ line: 27, column: 9 }],
+          path: ['subField', 'third'],
+        },
+        {
+          message: 'Cannot change the number',
+          locations: [{ line: 36, column: 9 }],
+          path: ['subField', 'sixth'],
+        },
       ],
     });
   });

src/execution/execute.js

@@ -1130,7 +1130,9 @@ function collectAndExecuteSubfields(
 ): MaybePromise<ObjMap<mixed>> {
   // Collect sub-fields to execute to complete this value.
   const subFieldNodes = collectSubfields(exeContext, returnType, fieldNodes);
-  return executeFields(exeContext, returnType, result, path, subFieldNodes);
+  return exeContext.operation.operation === 'mutation'
+    ? executeFieldsSerially(exeContext, returnType, result, path, subFieldNodes)
+    : executeFields(exeContext, returnType, result, path, subFieldNodes);
 }
 
 /**