From 9cd6d1f8dde97bea3d6cef7546d497f1bfdaf036 Mon Sep 17 00:00:00 2001
From: Joel Kemp <mrjoelkemp@gmail.com>
Date: Thu, 2 Jan 2014 18:42:28 -0500
Subject: [PATCH] Fixes #22

---
 Cocktail.js               |  4 ++++
 Cocktail.min.js           |  2 +-
 README.md                 |  5 ++++-
 spec/spec/CocktailSpec.js | 28 ++++++++++++++++++++++++++++
 4 files changed, 37 insertions(+), 2 deletions(-)

diff --git a/Cocktail.js b/Cocktail.js
index d2e327e..a0b57a6 100644
--- a/Cocktail.js
+++ b/Cocktail.js
@@ -30,6 +30,10 @@
             }
             _(mixin).each(function(value, key) {
                 if (_.isFunction(value)) {
+                    // If the mixer already has that exact function reference
+                    // Note: this would occur on an accidental mixin of the same base
+                    if (obj[key] === value) return;
+
                     if (obj[key]) {
                         collisions[key] = collisions[key] || [obj[key]];
                         collisions[key].push(value);
diff --git a/Cocktail.min.js b/Cocktail.min.js
index fcea40d..0106d1e 100644
--- a/Cocktail.min.js
+++ b/Cocktail.min.js
@@ -1 +1 @@
-(function(){var e={};typeof exports!="undefined"?e=exports:typeof define=="function"?define(function(t){return e}):this.Cocktail=e;e.mixins={};e.mixin=function(n){var r=_.chain(arguments).toArray().rest().flatten().value(),i=n.prototype||n,s={};_(r).each(function(t){_.isString(t)&&(t=e.mixins[t]);_(t).each(function(e,t){if(_.isFunction(e)){if(i[t]){s[t]=s[t]||[i[t]];s[t].push(e)}i[t]=e}else _.isObject(e)?i[t]=_.extend({},e,i[t]||{}):t in i||(i[t]=e)})});_(s).each(function(e,t){i[t]=function(){var t=this,n=arguments,r;_(e).each(function(e){var i=_.isFunction(e)?e.apply(t,n):e;r=typeof i=="undefined"?r:i});return r}})};var t;e.patch=function(r){t=r.Model.extend;var i=function(n,r){var i=t.call(this,n,r),s=i.prototype.mixins;s&&i.prototype.hasOwnProperty("mixins")&&e.mixin(i,s);return i};_([r.Model,r.Collection,r.Router,r.View]).each(function(t){t.mixin=function(){e.mixin(this,_.toArray(arguments))};t.extend=i})};e.unpatch=function(n){_([n.Model,n.Collection,n.Router,n.View]).each(function(e){e.mixin=undefined;e.extend=t})}})();
\ No newline at end of file
+(function(){var e={};typeof exports!="undefined"?e=exports:typeof define=="function"?define(function(t){return e}):this.Cocktail=e;e.mixins={};e.mixin=function(n){var r=_.chain(arguments).toArray().rest().flatten().value(),i=n.prototype||n,s={};_(r).each(function(t){_.isString(t)&&(t=e.mixins[t]);_(t).each(function(e,t){if(_.isFunction(e)){if(i[t]===e)return;if(i[t]){s[t]=s[t]||[i[t]];s[t].push(e)}i[t]=e}else _.isObject(e)?i[t]=_.extend({},e,i[t]||{}):t in i||(i[t]=e)})});_(s).each(function(e,t){i[t]=function(){var t=this,n=arguments,r;_(e).each(function(e){var i=_.isFunction(e)?e.apply(t,n):e;r=typeof i=="undefined"?r:i});return r}})};var t;e.patch=function(r){t=r.Model.extend;var i=function(n,r){var i=t.call(this,n,r),s=i.prototype.mixins;s&&i.prototype.hasOwnProperty("mixins")&&e.mixin(i,s);return i};_([r.Model,r.Collection,r.Router,r.View]).each(function(t){t.mixin=function(){e.mixin(this,_.toArray(arguments))};t.extend=i})};e.unpatch=function(n){_([n.Model,n.Collection,n.Router,n.View]).each(function(e){e.mixin=undefined;e.extend=t})}})();
\ No newline at end of file
diff --git a/README.md b/README.md
index a5a0bbd..a64dafd 100644
--- a/README.md
+++ b/README.md
@@ -133,7 +133,10 @@ Whether or not you're monkey patching Backbone, you can also use named mixins by
 
 In the example above, both `MyView` and `SelectMixin` both defined `initialize`, and `render`.  What happens with these colliding methods?
 
-Cocktail automatically ensures that methods defined in your mixins do not obliterate the corresponding methods in your classes.  This is accomplished by wrapping all colliding methods into a new method that is then assigned to the final composite object.
+Cocktail automatically ensures that methods defined in your mixins do not obliterate the corresponding methods in your classes.  
+This is accomplished by wrapping all colliding methods into a new method that is then assigned to the final composite object.
+
+Note: Cocktail will ensure that if you accidentally try to mix in the same method, it will not result in a collision and will do nothing.
 
 ### How are colliding functions called?
 
diff --git a/spec/spec/CocktailSpec.js b/spec/spec/CocktailSpec.js
index 64f77b6..12886c5 100644
--- a/spec/spec/CocktailSpec.js
+++ b/spec/spec/CocktailSpec.js
@@ -162,6 +162,34 @@ describe('Cocktail', function() {
             view.fooBar();
             expect(calls).toEqual(['fooBarOriginal', 'fooBarInclude']);
         });
+
+        it("should not mixin the same function reference more than once", function () {
+            var A = {
+                foo: function () {
+                    console.log('foo');
+                }
+            };
+
+            var B = {};
+
+            var C = {
+                foo: function () {
+                    console.log('foo');
+                }
+            };
+
+            Cocktail.mixin(B, A);
+            expect(B.foo === A.foo).toBeTruthy();
+
+            // An accidental mixin of the same base
+            Cocktail.mixin(B, A);
+            expect(B.foo === A.foo).toBeTruthy();
+
+            // Expect the collision wrapper
+            Cocktail.mixin(B, C);
+            expect(B.foo === A.foo).toBeFalsy();
+            expect(B.foo === C.foo).toBeFalsy();
+        });
     });
 
     describe("when patching backbone", function() {