From 05e3ea0a938fa048c2827869818dd085910a5026 Mon Sep 17 00:00:00 2001
From: Julien Sanchez <julien.sanchez@gmail.com>
Date: Tue, 1 Jul 2014 16:27:36 +0200
Subject: [PATCH] fix(copy): preserve property descriptors

Instead of values being simply copied, this change allows to preserve
definitions of own properties. Thus, enumerable (or not), writable (or
not), getter/setter, etc. property definitions are preserved across copies. It
improves change from b59b04f9 preserving prototype chain.

As a side effect, it also includes previously ignored non-enumerable properties
by using `Object.getOwnPropertyNames` to iterate **every** own properties instead
of `for ... in ...` + `hasOwnProperty`.
---
 src/Angular.js      | 18 +++++++++-------
 test/AngularSpec.js | 51 +++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 61 insertions(+), 8 deletions(-)

diff --git a/src/Angular.js b/src/Angular.js
index b84b156f72e4..e3d010650e86 100644
--- a/src/Angular.js
+++ b/src/Angular.js
@@ -807,16 +807,18 @@ function copy(source, destination, stackSource, stackDest) {
       forEach(destination, function(value, key) {
         delete destination[key];
       });
-      for ( var key in source) {
-        if(source.hasOwnProperty(key)) {
-          result = copy(source[key], null, stackSource, stackDest);
-          if (isObject(source[key])) {
-            stackSource.push(source[key]);
-            stackDest.push(result);
+      forEach (Object.getOwnPropertyNames(source), function(key) {
+        var propertyDescriptor = Object.getOwnPropertyDescriptor(source, key);
+        if (propertyDescriptor.hasOwnProperty('value')) {
+          var sourceValue = propertyDescriptor.value;
+          propertyDescriptor.value = copy(sourceValue, null, stackSource, stackDest);
+          if (isObject(sourceValue)) {
+            stackSource.push(sourceValue);
+            stackDest.push(propertyDescriptor.value);
           }
-          destination[key] = result;
         }
-      }
+        Object.defineProperty(destination, key, propertyDescriptor);
+      });
       setHashKey(destination,h);
     }
 
diff --git a/test/AngularSpec.js b/test/AngularSpec.js
index fea74f81212a..a329b47d8272 100644
--- a/test/AngularSpec.js
+++ b/test/AngularSpec.js
@@ -34,6 +34,57 @@ describe('angular', function() {
       expect(copy(new Foo()) instanceof Foo).toBe(true);
     });
 
+    it("should copy own non-enumerable properties", function() {
+      var obj = {
+        a: "enumerable"
+      };
+      Object.defineProperty(obj, 'b', {
+        value: "nonEnumerable",
+        enumerable: false
+      });
+      expect(copy(obj).a).toEqual("enumerable");
+      expect(copy(obj).b).toEqual("nonEnumerable");
+    });
+
+    it("should preserve own property descriptors", function() {
+      var obj = {};
+      var aDescriptor = {
+        value : {foo: 'a'},
+        writable : true,
+        enumerable : true,
+        configurable : true
+      };
+      var bDescriptor = {
+        value : {foo: 'b'},
+        writable : false,
+        enumerable : false,
+        configurable : false
+      };
+      var cDescriptor = {
+        get : function() { return this._c; },
+        set : function(newValue) { this._c = newValue; },
+        enumerable : false,
+        configurable : false
+      };
+      Object.defineProperties(obj, {
+        a: aDescriptor,
+        b: bDescriptor,
+        c: cDescriptor
+      });
+      obj.c = {foo: 'b'};
+
+      var objCopy = copy(obj);
+      expect(Object.getOwnPropertyDescriptor(objCopy, "a")).toEqual(aDescriptor);
+      expect(Object.getOwnPropertyDescriptor(objCopy, "b")).toEqual(bDescriptor);
+      expect(Object.getOwnPropertyDescriptor(objCopy, "c")).toEqual(cDescriptor);
+      expect(objCopy.a).toEqual(obj.a);
+      expect(objCopy.a === obj.a).toBe(false);
+      expect(objCopy.b).toEqual(obj.b);
+      expect(objCopy.b === obj.b).toBe(false);
+      expect(objCopy.c).toEqual(obj.c);
+      expect(objCopy.c === obj.c).toBe(false);
+    });
+
     it("should copy Date", function() {
       var date = new Date(123);
       expect(copy(date) instanceof Date).toBeTruthy();