1 files changed, 20 insertions, 0 deletions
diff --git a/src/Angular.js b/src/Angular.js
index bf64c6c2..45023d6c 100644
--- a/src/Angular.js
+++ b/src/Angular.js
@@ -215,6 +215,21 @@ function nextUid() {
   return uid.join('');
 }
 
+
+/**
+ * Set or clear the hashkey for an object.
+ * @param obj object 
+ * @param h the hashkey (!truthy to delete the hashkey)
+ */
+function setHashKey(obj, h) {
+  if (h) {
+    obj.$$hashKey = h;
+  }
+  else {
+    delete obj.$$hashKey;
+  }
+}
+
 /**
  * @ngdoc function
  * @name angular.extend
@@ -228,6 +243,7 @@ function nextUid() {
  * @param {...Object} src Source object(s).
  */
 function extend(dst) {
+  var h = dst.$$hashKey;
   forEach(arguments, function(obj){
     if (obj !== dst) {
       forEach(obj, function(value, key){
@@ -235,6 +251,8 @@ function extend(dst) {
       });
     }
   });
+
+  setHashKey(dst,h);
   return dst;
 }
 
@@ -594,12 +612,14 @@ function copy(source, destination){
         destination.push(copy(source[i]));
       }
     } else {
+      var h = destination.$$hashKey;
       forEach(destination, function(value, key){
         delete destination[key];
       });
       for ( var key in source) {
         destination[key] = copy(source[key]);
       }
+      setHashKey(destination,h);
     }
   }
   return destination;