model#parse may no longer set the idAttribute

backbone.js

@@ -112,7 +112,6 @@
         this._events = {};
         return this;
       }
-
       names = name ? [name] : _.keys(this._events);
       for (i = 0, l = names.length; i < l; i++) {
         name = names[i];
@@ -252,7 +251,6 @@
     this.attributes = {};
     if (options.collection) this.collection = options.collection;
     if (options.parse) attrs = this.parse(attrs, options) || {};
-    options._attrs || (options._attrs = attrs);
     if (defaults = _.result(this, 'defaults')) {
       attrs = _.defaults({}, attrs, defaults);
     }
@@ -667,8 +665,9 @@
       options = _.defaults({}, options, setOptions);
       if (options.parse) models = this.parse(models, options);
       if (!_.isArray(models)) models = models ? [models] : [];
-      var i, l, model, attrs, existing, sort;
+      var i, l, id, model, attrs, existing, sort;
       var at = options.at;
+      var targetModel = this.model;
       var sortable = this.comparator && (at == null) && options.sort !== false;
       var sortAttr = _.isString(this.comparator) ? this.comparator : null;
       var toAdd = [], toRemove = [], modelMap = {};
@@ -678,20 +677,27 @@
       // Turn bare objects into model references, and prevent invalid models
       // from being added.
       for (i = 0, l = models.length; i < l; i++) {
-        if (!(model = this._prepareModel(attrs = models[i], options))) continue;
+        attrs = models[i];
+        if (attrs instanceof Model) {
+          id = model = attrs;
+        } else {
+          id = attrs[targetModel.prototype.idAttribute];
+        }
 
         // If a duplicate is found, prevent it from being added and
         // optionally merge it into the existing model.
-        if (existing = this.get(model)) {
+        if (existing = this.get(id)) {
           if (remove) modelMap[existing.cid] = true;
           if (merge) {
-            attrs = attrs === model ? model.attributes : options._attrs;
+            attrs = attrs === model ? model.attributes : attrs;
+            if (options.parse) attrs = existing.parse(attrs, options);
             existing.set(attrs, options);
             if (sortable && !sort && existing.hasChanged(sortAttr)) sort = true;
           }
 
         // This is a new model, push it to the `toAdd` list.
         } else if (add) {
+          if (!(model = this._prepareModel(attrs, options))) continue;
           toAdd.push(model);
 
           // Listen to added models' events, and index models for lookup by
@@ -701,7 +707,6 @@
           if (model.id != null) this._byId[model.id] = model;
         }
         if (order) order.push(existing || model);
-        delete options._attrs;
       }
 
       // Remove nonexistent models if appropriate.

test/collection.js

@@ -225,13 +225,13 @@ $(document).ready(function() {
   });
 
   test("add with parse and merge", function() {
-    var Model = Backbone.Model.extend({
-      parse: function (data) {
-        return data.model;
-      }
-    });
     var collection = new Backbone.Collection();
-    collection.model = Model;
+    collection.parse = function(attrs) {
+      return _.map(attrs, function(model) {
+        if (model.model) return model.model;
+        return model;
+      });
+    };
     collection.add({id: 1});
     collection.add({model: {id: 1, name: 'Alf'}}, {parse: true, merge: true});
     equal(collection.first().get('name'), 'Alf');
@@ -975,12 +975,10 @@ $(document).ready(function() {
   });
 
   test("`set` and model level `parse`", function() {
-    var Model = Backbone.Model.extend({
-      parse: function (res) { return res.model; }
-    });
+    var Model = Backbone.Model.extend({});
     var Collection = Backbone.Collection.extend({
       model: Model,
-      parse: function (res) { return res.models; }
+      parse: function (res) { return _.pluck(res.models, 'model'); }
     });
     var model = new Model({id: 1});
     var collection = new Collection(model);