Throw error when setting authData to null

spec/MongoTransform.spec.js

@@ -479,6 +479,46 @@ describe('parseObjectToMongoObjectForCreate', () => {
     }).toThrow();
     done();
   });
+
+  it('ignores User authData field in DB so it can be synthesized in code', done => {
+    const input = {
+      _id: '123',
+      _auth_data_acme: { id: 'abc' },
+      authData: null,
+    };
+    const output = transform.mongoObjectToParseObject('_User', input, {
+      fields: {},
+    });
+    expect(output.authData.acme.id).toBe('abc');
+    done();
+  });
+
+  it('can set authData when not User class', done => {
+    const input = {
+      _id: '123',
+      authData: 'random',
+    };
+    const output = transform.mongoObjectToParseObject('TestObject', input, {
+      fields: {},
+    });
+    expect(output.authData).toBe('random');
+    done();
+  });
+});
+
+it('cannot have a custom field name beginning with underscore', done => {
+  const input = {
+    _id: '123',
+    _thisFieldNameIs: 'invalid',
+  };
+  try {
+    transform.mongoObjectToParseObject('TestObject', input, {
+      fields: {},
+    });
+  } catch (e) {
+    expect(e).toBeDefined();
+  }
+  done();
 });
 
 describe('transformUpdate', () => {

spec/ParseObject.spec.js

@@ -276,6 +276,16 @@ describe('Parse.Object testing', () => {
     done();
   });
 
+  it('can set authData when not user class', async () => {
+    const obj = new Parse.Object('TestObject');
+    obj.set('authData', 'random');
+    await obj.save();
+    expect(obj.get('authData')).toBe('random');
+    const query = new Parse.Query('TestObject');
+    const object = await query.get(obj.id, { useMasterKey: true });
+    expect(object.get('authData')).toBe('random');
+  });
+
   it('invalid class name', function(done) {
     const item = new Parse.Object('Foo^bar');
     item.save().then(

spec/ParseUser.spec.js

@@ -1246,6 +1246,32 @@ describe('Parse.User testing', () => {
     done();
   });
 
+  it('can not set authdata to null', async () => {
+    try {
+      const provider = getMockFacebookProvider();
+      Parse.User._registerAuthenticationProvider(provider);
+      const user = await Parse.User._logInWith('facebook');
+      user.set('authData', null);
+      await user.save();
+      fail();
+    } catch (e) {
+      expect(e.message).toBe('This authentication method is unsupported.');
+    }
+  });
+
+  it('ignore setting authdata to undefined', async () => {
+    const provider = getMockFacebookProvider();
+    Parse.User._registerAuthenticationProvider(provider);
+    const user = await Parse.User._logInWith('facebook');
+    user.set('authData', undefined);
+    await user.save();
+    let authData = user.get('authData');
+    expect(authData).toBe(undefined);
+    await user.fetch();
+    authData = user.get('authData');
+    expect(authData.facebook.id).toBeDefined();
+  });
+
   it('user authData should be available in cloudcode (#2342)', async done => {
     Parse.Cloud.define('checkLogin', req => {
       expect(req.user).not.toBeUndefined();
@@ -3924,4 +3950,29 @@ describe('Security Advisory GHSA-8w3j-g983-8jh5', function() {
       done();
     }
   );
+  it_only_db('mongo')('should ignore authData field', async () => {
+    // Add User to Database with authData
+    const database = Config.get(Parse.applicationId).database;
+    const collection = await database.adapter._adaptiveCollection('_User');
+    await collection.insertOne({
+      _id: '1234ABCDEF',
+      name: '<some_name>',
+      email: '<some_email>',
+      username: '<some_username>',
+      _hashed_password: '<some_password>',
+      _auth_data_custom: {
+        id: 'linkedID',
+      },
+      sessionToken: '<some_session_token>',
+      authData: null, // should ignore
+    });
+    const provider = {
+      getAuthType: () => 'custom',
+      restoreAuthentication: () => true,
+    };
+    Parse.User._registerAuthenticationProvider(provider);
+    const query = new Parse.Query(Parse.User);
+    const user = await query.get('1234ABCDEF', { useMasterKey: true });
+    expect(user.get('authData')).toEqual({ custom: { id: 'linkedID' } });
+  });
 });

src/Adapters/Storage/Mongo/MongoTransform.js

@@ -1403,10 +1403,19 @@ const mongoObjectToParseObject = (className, mongoObject, schema) => {
           case 'times_used':
             restObject['timesUsed'] = mongoObject[key];
             break;
+          case 'authData':
+            if (className === '_User') {
+              log.warn(
+                'ignoring authData in _User as this key is reserved to be synthesized of `_auth_data_*` keys'
+              );
+            } else {
+              restObject['authData'] = mongoObject[key];
+            }
+            break;
           default:
             // Check other auth data keys
             var authDataMatch = key.match(/^_auth_data_([a-zA-Z0-9_]+)$/);
-            if (authDataMatch) {
+            if (authDataMatch && className === '_User') {
               var provider = authDataMatch[1];
               restObject['authData'] = restObject['authData'] || {};
               restObject['authData'][provider] = mongoObject[key];

src/RestWrite.js

@@ -417,8 +417,21 @@ RestWrite.prototype.validateAuthData = function() {
     }
   }
 
-  if (!this.data.authData || !Object.keys(this.data.authData).length) {
+  if (
+    (this.data.authData && !Object.keys(this.data.authData).length) ||
+    !Object.prototype.hasOwnProperty.call(this.data, 'authData')
+  ) {
+    // Handle saving authData to {} or if authData doesn't exist
     return;
+  } else if (
+    Object.prototype.hasOwnProperty.call(this.data, 'authData') &&
+    !this.data.authData
+  ) {
+    // Handle saving authData to null
+    throw new Parse.Error(
+      Parse.Error.UNSUPPORTED_SERVICE,
+      'This authentication method is unsupported.'
+    );
   }
 
   var authData = this.data.authData;