fix(ngSwitch): don't leak when destroyed while not attached

The leak can occur when ngSwich is used inside ngRepeat or any other
directive which is destroyed while its transcluded content (which
includes ngSwitch) is not attached to the DOM.

Refactor ngSwitch to use controller instead of storing data on compile
node. This means that we don't need to clean up the jq data cache.
Controller reference is released when the linking fn is released.

Closes #1621

2 files changed, 46 insertions, 30 deletions

diff --git a/src/ng/directive/ngSwitch.js b/src/ng/directive/ngSwitch.js
index 0c9e2a8d..24c6047a 100644
--- a/src/ng/directive/ngSwitch.js
+++ b/src/ng/directive/ngSwitch.js
@@ -62,51 +62,52 @@
 var NG_SWITCH = 'ng-switch';
 var ngSwitchDirective = valueFn({
   restrict: 'EA',
-  compile: function(element, attr) {
+  require: 'ngSwitch',
+  controller: function ngSwitchController() {
+    this.cases = {};
+  },
+  link: function(scope, element, attr, ctrl) {
     var watchExpr = attr.ngSwitch || attr.on,
-        cases = {};
+        selectedTransclude,
+        selectedElement,
+        selectedScope;
 
-    element.data(NG_SWITCH, cases);
-    return function(scope, element){
-      var selectedTransclude,
-          selectedElement,
-          selectedScope;
-
-      scope.$watch(watchExpr, function ngSwitchWatchAction(value) {
-        if (selectedElement) {
-          selectedScope.$destroy();
-          selectedElement.remove();
-          selectedElement = selectedScope = null;
-        }
-        if ((selectedTransclude = cases['!' + value] || cases['?'])) {
-          scope.$eval(attr.change);
-          selectedScope = scope.$new();
-          selectedTransclude(selectedScope, function(caseElement) {
-            selectedElement = caseElement;
-            element.append(caseElement);
-          });
-        }
-      });
-    };
+    scope.$watch(watchExpr, function ngSwitchWatchAction(value) {
+      if (selectedElement) {
+        selectedScope.$destroy();
+        selectedElement.remove();
+        selectedElement = selectedScope = null;
+      }
+      if ((selectedTransclude = ctrl.cases['!' + value] || ctrl.cases['?'])) {
+        scope.$eval(attr.change);
+        selectedScope = scope.$new();
+        selectedTransclude(selectedScope, function(caseElement) {
+          selectedElement = caseElement;
+          element.append(caseElement);
+        });
+      }
+    });
   }
 });
 
 var ngSwitchWhenDirective = ngDirective({
   transclude: 'element',
   priority: 500,
+  require: '^ngSwitch',
   compile: function(element, attrs, transclude) {
-    var cases = element.inheritedData(NG_SWITCH);
-    assertArg(cases);
-    cases['!' + attrs.ngSwitchWhen] = transclude;
+    return function(scope, element, attr, ctrl) {
+      ctrl.cases['!' + attrs.ngSwitchWhen] = transclude;
+    };
   }
 });
 
 var ngSwitchDefaultDirective = ngDirective({
   transclude: 'element',
   priority: 500,
+  require: '^ngSwitch',
   compile: function(element, attrs, transclude) {
-    var cases = element.inheritedData(NG_SWITCH);
-    assertArg(cases);
-    cases['?'] = transclude;
+    return function(scope, element, attr, ctrl) {
+      ctrl.cases['?'] = transclude;
+    };
   }
 });
diff --git a/test/ng/directive/ngSwitchSpec.js b/test/ng/directive/ngSwitchSpec.js
index 66ae5562..ee91f79d 100644
--- a/test/ng/directive/ngSwitchSpec.js
+++ b/test/ng/directive/ngSwitchSpec.js
@@ -90,4 +90,19 @@ describe('ngSwitch', function() {
     expect(child2).toBeDefined();
     expect(child2).not.toBe(child1);
   }));
+
+
+  it('should not leak jq data when compiled but not attached to parent when parent is destroyed',
+      inject(function($rootScope, $compile) {
+    element = $compile(
+      '<div ng-repeat="i in []">' +
+        '<ng-switch on="url">' +
+          '<div ng-switch-when="a">{{name}}</div>' +
+        '</ng-switch>' +
+      '</div>')($rootScope);
+    $rootScope.$apply();
+
+    // element now contains only empty repeater. this element is dealocated by local afterEach.
+    // afterwards a global afterEach will check for leaks in jq data cache object
+  }));
 });