From 4b97ff8a0d4591fdf1ba99d748c078a06d9044e0 Mon Sep 17 00:00:00 2001
From: Martin Staffa <mjstaffa@googlemail.com>
Date: Mon, 23 Mar 2015 23:07:04 +0100
Subject: [PATCH] fix(select): don't call $render twice if $viewValue ref
 changes

Credits to @tepez for the fix

Closes #11329
---
 src/ng/directive/select.js      |  4 ++-
 test/ng/directive/selectSpec.js | 54 +++++++++++++++++++++++++++++++++
 2 files changed, 57 insertions(+), 1 deletion(-)

diff --git a/src/ng/directive/select.js b/src/ng/directive/select.js
index 66e48bc0ef9d..dee4940688d1 100644
--- a/src/ng/directive/select.js
+++ b/src/ng/directive/select.js
@@ -200,11 +200,13 @@ var selectDirective = function() {
 
         // we have to do it on each watch since ngModel watches reference, but
         // we need to work of an array, so we need to see if anything was inserted/removed
+        var lastView, lastViewRef = NaN;
         scope.$watch(function selectMultipleWatch() {
-          if (!equals(lastView, ngModelCtrl.$viewValue)) {
+          if (lastViewRef === ngModelCtrl.$viewValue && !equals(lastView, ngModelCtrl.$viewValue)) {
             lastView = shallowCopy(ngModelCtrl.$viewValue);
             ngModelCtrl.$render();
           }
+          lastViewRef = ngModelCtrl.$viewValue;
         });
 
         // If we are a multiple select then value is now a collection
diff --git a/test/ng/directive/selectSpec.js b/test/ng/directive/selectSpec.js
index af6262a56166..5be377aa54ee 100644
--- a/test/ng/directive/selectSpec.js
+++ b/test/ng/directive/selectSpec.js
@@ -841,6 +841,60 @@ describe('select', function() {
       expect(element).toBeDirty();
     });
 
+
+    describe('calls to $render', function() {
+
+      var ngModelCtrl;
+
+      beforeEach(function() {
+        compile(
+          '<select name="select" ng-model="selection" multiple>' +
+          '<option>A</option>' +
+          '<option>B</option>' +
+          '</select>');
+
+        ngModelCtrl = element.controller('ngModel');
+        spyOn(ngModelCtrl, '$render').andCallThrough();
+      });
+
+
+      it('should call $render once when the reference to the viewValue changes', function() {
+        scope.$apply(function() {
+          scope.selection = ['A'];
+        });
+        expect(ngModelCtrl.$render.calls.length).toBe(1);
+
+        scope.$apply(function() {
+          scope.selection = ['A', 'B'];
+        });
+        expect(ngModelCtrl.$render.calls.length).toBe(2);
+
+        scope.$apply(function() {
+          scope.selection = [];
+        });
+        expect(ngModelCtrl.$render.calls.length).toBe(3);
+      });
+
+
+      it('should call $render once when the viewValue deep-changes', function() {
+        scope.$apply(function() {
+          scope.selection = ['A'];
+        });
+        expect(ngModelCtrl.$render.calls.length).toBe(1);
+
+        scope.$apply(function() {
+          scope.selection.push('B');
+        });
+        expect(ngModelCtrl.$render.calls.length).toBe(2);
+
+        scope.$apply(function() {
+          scope.selection.length = 0;
+        });
+        expect(ngModelCtrl.$render.calls.length).toBe(3);
+      });
+
+    });
+
   });