Tweak add implementation.

backbone.js

@@ -597,19 +597,19 @@
     // Add a model, or list of models to the set. Pass **silent** to avoid
     // firing the `add` event for every new model.
     add: function(models, options) {
-      var i, args, length, model, existing, valid;
+      var i, args, length, model, existing;
       var at = options && options.at;
       models = _.isArray(models) ? models.slice() : [models];
 
-      // Begin by turning bare objects into model references, and preventing
-      // invalid models from being added.
-      valid = [];
-      for (i = 0, length = models.length; i < length; i++) {
-        model = this._prepareModel(models[i], options);
-        if(!model) {
-            this.trigger("error", this, "Can't add an invalid model to a collection", models[i]);
+      for (i = models.length - 1; i >= 0; i--) {
+        // Turn bare objects into model references, and prevent invalid models
+        // from being added.
+        if(!(model = this._prepareModel(models[i], options))) {
+            this.trigger("error", this, models[i], options);
+            models.splice(i, 1);
             continue;
         }
+        models[i] = model;
 
         existing = model.id != null && this._byId[model.id];
         // If a duplicate is found, prevent it from being added and
@@ -618,10 +618,10 @@
           if (options && options.merge && existing) {
             existing.set(model, options);
           }
+          models.splice(i, 1);
           continue;
         }
 
-        valid.push(model);
         // Listen to added models' events, and index models for lookup by
         // `id` and by `cid`.
         model.on('all', this._onModelEvent, this);
@@ -630,9 +630,9 @@
       }
 
       // Update `length` and splice in new models.
-      this.length += valid.length;
+      this.length += models.length;
       args = [at != null ? at : this.models.length, 0];
-      push.apply(args, valid);
+      push.apply(args, models);
       splice.apply(this.models, args);
 
       // Sort the collection if appropriate.
@@ -641,7 +641,7 @@
       if (options && options.silent) return this;
 
       // Trigger `add` events.
-      while (model = valid.shift()) {
+      while (model = models.shift()) {
         model.trigger('add', model, this, options);
       }
 

test/collection.js

@@ -543,7 +543,6 @@ $(document).ready(function() {
   });
 
   test("#861, adding models to a collection which do not pass validation", 2, function() {
-      var fired = null;
       var Model = Backbone.Model.extend({
         validate: function(attrs) {
           if (attrs.id == 3) return "id can't be 3";
@@ -554,27 +553,26 @@ $(document).ready(function() {
         model: Model
       });
 
-      var col = new Collection;
-      col.on("error", function() { fired = true; });
+      var collection = new Collection;
+      collection.on("error", function() { ok(true); });
 
-      col.add([{id: 1}, {id: 2}, {id: 3}, {id: 4}, {id: 5}, {id: 6}]);
-      equal(fired, true);
-      equal(col.length, 5);
+      collection.add([{id: 1}, {id: 2}, {id: 3}, {id: 4}, {id: 5}, {id: 6}]);
+      deepEqual(collection.pluck('id'), [1, 2, 4, 5, 6]);
   });
 
-  test("invalid models are discarded and only valid models are added to a collection", 5, function() {
-    var col = new Backbone.Collection();
-    col.on('test', function() { ok(true); });
-    col.model = Backbone.Model.extend({
+  test("Invalid models are discarded.", 5, function() {
+    var collection = new Backbone.Collection;
+    collection.on('test', function() { ok(true); });
+    collection.model = Backbone.Model.extend({
       validate: function(attrs){ if (!attrs.valid) return 'invalid'; }
     });
-    var model = new col.model({id: 1, valid: true});
-    col.add([model, {id: 2}]);;
+    var model = new collection.model({id: 1, valid: true});
+    collection.add([model, {id: 2}]);;
     model.trigger('test');
-    ok(col.getByCid(model.cid));
-    ok(col.get(1));
-    ok(!col.get(2));
-    equal(col.length, 1);
+    ok(collection.getByCid(model.cid));
+    ok(collection.get(1));
+    ok(!collection.get(2));
+    equal(collection.length, 1);
   });
 
   test("multiple copies of the same model", 3, function() {