Fix issue with pointers getting un-hydrated when there is a beforeSave (#1884)

* Add failing test and simplify RestWrite

* simplify and add test stubs

* Fix issue

spec/CloudCode.spec.js

@@ -557,4 +557,36 @@ describe('Cloud Code', () => {
       });
     });
   });
+
+  it('trivial beforeSave should not affect fetched pointers (regression test for #1238)', done => {
+    Parse.Cloud.beforeSave('BeforeSaveUnchanged', (req, res) => {
+      res.success();
+    });
+
+    var TestObject =  Parse.Object.extend("TestObject");
+    var NoBeforeSaveObject = Parse.Object.extend("NoBeforeSave");
+    var BeforeSaveObject = Parse.Object.extend("BeforeSaveUnchanged");
+
+    var aTestObject = new TestObject();
+    aTestObject.set("foo", "bar");
+    aTestObject.save()
+    .then(aTestObject => {
+      var aNoBeforeSaveObj = new NoBeforeSaveObject();
+      aNoBeforeSaveObj.set("aTestObject", aTestObject);
+      expect(aNoBeforeSaveObj.get("aTestObject").get("foo")).toEqual("bar");
+      return aNoBeforeSaveObj.save();
+    })
+    .then(aNoBeforeSaveObj => {
+      expect(aNoBeforeSaveObj.get("aTestObject").get("foo")).toEqual("bar");
+
+      var aBeforeSaveObj = new BeforeSaveObject();
+      aBeforeSaveObj.set("aTestObject", aTestObject);
+      expect(aBeforeSaveObj.get("aTestObject").get("foo")).toEqual("bar");
+      return aBeforeSaveObj.save();
+    })
+    .then(aBeforeSaveObj => {
+      expect(aBeforeSaveObj.get("aTestObject").get("foo")).toEqual("bar");
+      done();
+    });
+  });
 });

src/RestWrite.js

@@ -12,6 +12,7 @@ var passwordCrypto = require('./password');
 var Parse = require('parse/node');
 var triggers = require('./triggers');
 import RestQuery from './RestQuery';
+import _         from 'lodash';
 
 // query and data are both provided in REST API format. So data
 // types are encoded by plain old objects.
@@ -165,8 +166,10 @@ RestWrite.prototype.runBeforeTrigger = function() {
     return triggers.maybeRunTrigger(triggers.Types.beforeSave, this.auth, updatedObject, originalObject, this.config);
   }).then((response) => {
     if (response && response.object) {
+      if (!_.isEqual(this.data, response.object)) {
+        this.storage.changedByTrigger = true;
+      }
       this.data = response.object;
-      this.storage['changedByTrigger'] = true;
       // We should delete the objectId for an update write
       if (this.query && this.query.objectId) {
         delete this.data.objectId
@@ -733,19 +736,16 @@ RestWrite.prototype.runDatabaseOperation = function() {
       this.data.ACL[this.query.objectId] = { read: true, write: true };
     }
     // Run an update
-    return this.config.database.update(
-      this.className, this.query, this.data, this.runOptions).then((resp) => {
-        resp.updatedAt = this.updatedAt;
-        if (this.storage['changedByTrigger']) {
-          resp = Object.keys(this.data).reduce((memo, key) => {
-            memo[key] = resp[key] || this.data[key];
-            return memo;
-          }, resp);
-        }
-        this.response = {
-          response: resp
-        };
-      });
+    return this.config.database.update(this.className, this.query, this.data, this.runOptions)
+    .then(response => {
+      response.updatedAt = this.updatedAt;
+      if (this.storage.changedByTrigger) {
+        Object.keys(this.data).forEach(fieldName => {
+          response[fieldName] = response[fieldName] || this.data[fieldName];
+        });
+      }
+      this.response = { response };
+    });
   } else {
     // Set the default ACL for the new _User
     if (this.className === '_User') {
@@ -762,23 +762,20 @@ RestWrite.prototype.runDatabaseOperation = function() {
 
     // Run a create
     return this.config.database.create(this.className, this.data, this.runOptions)
-      .then((resp) => {
-        Object.assign(resp, {
-          objectId: this.data.objectId,
-          createdAt: this.data.createdAt
+    .then(response => {
+      response.objectId = this.data.objectId;
+      response.createdAt = this.data.createdAt;
+      if (this.storage.changedByTrigger) {
+        Object.keys(this.data).forEach(fieldName => {
+          response[fieldName] = response[fieldName] || this.data[fieldName];
         });
-        if (this.storage['changedByTrigger']) {
-          resp = Object.keys(this.data).reduce((memo, key) => {
-            memo[key] = resp[key] || this.data[key];
-            return memo;
-          }, resp);
-        }
-        this.response = {
-          status: 201,
-          response: resp,
-          location: this.location()
-        };
-      });
+      }
+      this.response = {
+        status: 201,
+        response,
+        location: this.location()
+      };
+    });
   }
 };