From 5c99720934edc35dd462b1ad02c4d0205683d917 Mon Sep 17 00:00:00 2001
From: rodyhaddad <rody@rodyhaddad.com>
Date: Wed, 28 May 2014 12:14:08 -0700
Subject: [PATCH] fix(angular.copy): support circular references in the value
 being copied

Closes #7618
---
 src/Angular.js      | 34 +++++++++++++++++++++++++++++-----
 src/ng/rootScope.js |  2 +-
 test/AngularSpec.js | 14 ++++++++++++++
 3 files changed, 44 insertions(+), 6 deletions(-)

diff --git a/src/Angular.js b/src/Angular.js
index b9658021a..3b632a75b 100644
--- a/src/Angular.js
+++ b/src/Angular.js
@@ -757,7 +757,7 @@ function isLeafNode (node) {
  </file>
  </example>
  */
-function copy(source, destination) {
+function copy(source, destination, stackSource, stackDest) {
   if (isWindow(source) || isScope(source)) {
     throw ngMinErr('cpws',
       "Can't copy! Making copies of Window or Scope instances is not supported.");
@@ -767,22 +767,40 @@ function copy(source, destination) {
     destination = source;
     if (source) {
       if (isArray(source)) {
-        destination = copy(source, []);
+        destination = copy(source, [], stackSource, stackDest);
       } else if (isDate(source)) {
         destination = new Date(source.getTime());
       } else if (isRegExp(source)) {
         destination = new RegExp(source.source);
       } else if (isObject(source)) {
-        destination = copy(source, {});
+        destination = copy(source, {}, stackSource, stackDest);
       }
     }
   } else {
     if (source === destination) throw ngMinErr('cpi',
       "Can't copy! Source and destination are identical.");
+
+    stackSource = stackSource || [];
+    stackDest = stackDest || [];
+
+    if (isObject(source)) {
+      var index = indexOf(stackSource, source);
+      if (index !== -1) return stackDest[index];
+
+      stackSource.push(source);
+      stackDest.push(destination);
+    }
+
+    var result;
     if (isArray(source)) {
       destination.length = 0;
       for ( var i = 0; i < source.length; i++) {
-        destination.push(copy(source[i]));
+        result = copy(source[i], null, stackSource, stackDest);
+        if (isObject(source[i])) {
+          stackSource.push(source[i]);
+          stackDest.push(result);
+        }
+        destination.push(result);
       }
     } else {
       var h = destination.$$hashKey;
@@ -790,10 +808,16 @@ function copy(source, destination) {
         delete destination[key];
       });
       for ( var key in source) {
-        destination[key] = copy(source[key]);
+        result = copy(source[key], null, stackSource, stackDest);
+        if (isObject(source[key])) {
+          stackSource.push(source[key]);
+          stackDest.push(result);
+        }
+        destination[key] = result;
       }
       setHashKey(destination,h);
     }
+
   }
   return destination;
 }
diff --git a/src/ng/rootScope.js b/src/ng/rootScope.js
index 6bcee4053..d31ba3d24 100644
--- a/src/ng/rootScope.js
+++ b/src/ng/rootScope.js
@@ -643,7 +643,7 @@ function $RootScopeProvider(){
                                && isNaN(value) && isNaN(last)))) {
                       dirty = true;
                       lastDirtyWatch = watch;
-                      watch.last = watch.eq ? copy(value) : value;
+                      watch.last = watch.eq ? copy(value, null) : value;
                       watch.fn(value, ((last === initWatchVal) ? value : last), current);
                       if (ttl < 5) {
                         logIdx = 4 - ttl;
diff --git a/test/AngularSpec.js b/test/AngularSpec.js
index 1869611cd..ea7204660 100644
--- a/test/AngularSpec.js
+++ b/test/AngularSpec.js
@@ -146,6 +146,20 @@ describe('angular', function() {
       // make sure we retain the old key
       expect(hashKey(dst)).toEqual(h);
     });
+
+    it('should handle circular references when circularRefs is turned on', function () {
+      var a = {b: {a: null}, self: null, selfs: [null, null, [null]]};
+      a.b.a = a;
+      a.self = a;
+      a.selfs = [a, a.b, [a]];
+
+      var aCopy = copy(a, null);
+      expect(aCopy).toEqual(a);
+
+      expect(aCopy).not.toBe(a);
+      expect(aCopy).toBe(aCopy.self);
+      expect(aCopy.selfs[2]).not.toBe(a.selfs[2]);
+    });
   });
 
   describe("extend", function() {