Merge pull request #944 from strongloop/fix-mixin-err-handler

[SEMVER-MAJOR] throw error for undefined mixin

3.0-RELEASE-NOTES.md

@@ -5,6 +5,7 @@ always describe the impact on users and instructions for upgrading
 applications from 2.x to 3.0.
 
 See also https://github.com/strongloop/loopback/blob/master/3.0-DEVELOPING.md
+for more details.
 
 ## Always use bluebird as promise library
 
@@ -18,7 +19,8 @@ via `global.Promise`,
 you will have to check all places where you are using non-standard promise API
 and update them to use Bluebird API instead.
 
-Please see [Related code change](https://github.com/strongloop/loopback-datasource-juggler/pull/790) here.
+See [related code change](https://github.com/strongloop/loopback-datasource-juggler/pull/790)
+for more details.
 
 ## DAO.find provides ctx.data in "loaded" hook
 
@@ -33,7 +35,8 @@ This has been fixed in 3.0 and the "loaded" hook now consistently provides
 checks `if (ctx.instance)` then you can remove this condition together with
 the branch that follows.
 
-See also the commit [30283291](https://github.com/strongloop/loopback-datasource-juggler/commit/30283291?w=1)
+See [related code change](https://github.com/strongloop/loopback-datasource-juggler/commit/30283291?w=1)
+for more details.
 
 ## DAO.create no longer returns the instance(s) created
 
@@ -47,5 +50,15 @@ We have changed the API to be consistent with other DAO methods: when invoked
 with a callback argument, the method does not return anything. When invoked
 without any callback, a promise is returned.
 
-See [pull request 918](https://github.com/strongloop/loopback-datasource-juggler/pull/918)
+See [related code change](https://github.com/strongloop/loopback-datasource-juggler/pull/918)
+for more details.
+
+## Applying an undefined mixin to a LoopBack model throws an error
+
+When applying an undefined mixin to a LoopBack model, a warning message was
+logged regarding the invalid mixin, which needs to be addressed rather than
+silently ignored. This has been fixed in 3.0, therefore an undefined mixin
+applied to a LoopBack model will throw an error that needs to be handled.
+
+See [related code change](https://github.com/strongloop/loopback-datasource-juggler/pull/944)
 for more details.

lib/mixins.js

@@ -44,7 +44,9 @@ MixinProvider.prototype.applyMixin = function applyMixin(modelClass, name, optio
       debug('Mixin is resolved to a model: %s', name);
       modelClass.mixin(model, options);
     } else {
-      debug('Invalid mixin: %s', name);
+      var errMsg = 'Model "' + modelClass.modelName + '" uses unknown mixin: ' + name;
+      debug(errMsg);
+      throw new Error(errMsg);
     }
   }
 };
@@ -69,4 +71,3 @@ MixinProvider.prototype.define = function defineMixin(name, mixin) {
     this.mixins[name] = mixin;
   }
 };
-

test/mixins.test.js

@@ -79,11 +79,22 @@ describe('Model class', function() {
     properties.city.should.eql({ type: String, required: true });
   });
 
+  it('should fail to apply an undefined mixin class', function() {
+    var memory = new DataSource('mem', { connector: Memory }, modelBuilder);
+    function applyMixin() {
+      memory.createModel('Item', { name: 'string' }, {
+        mixins: { UndefinedMixin: true },
+      });
+    }
+    should.throws(applyMixin, 'failed to apply undefined mixin class');
+  });
+
   it('should apply mixins', function(done) {
     var memory = new DataSource('mem', { connector: Memory }, modelBuilder);
     var Item = memory.createModel('Item', { name: 'string' }, {
       mixins: {
-        TimeStamp: true, Demo: { value: true },
+        TimeStamp: true,
+        Demo: { value: true },
         Multi: [
           { key: 'foo', value: 'bar' },
           { key: 'fox', value: 'baz' },
@@ -110,6 +121,16 @@ describe('Model class', function() {
     });
   });
 
+  it('should fail to apply undefined mixin', function() {
+    var memory = new DataSource('mem', { connector: Memory }, modelBuilder);
+    var Item = memory.createModel('Item', { name: 'string' });
+
+    function applyMixin() {
+      Item.mixin('UndefinedMixin', { foo: 'bar' });
+    }
+    should.throws(applyMixin, 'failed to apply undefined mixin');
+  });
+
   describe('#mixin()', function() {
 
     var Person, Author, Address;