fix(tooltip): memory leak on show/hide

Create a new child scope and retain a reference to it so that it can
be destroyed when the tooltip DOM is removed.

Fixes angular-ui#2709
Closes angular-ui#2919

Author: chrisirhc

src/tooltip/test/tooltip.spec.js

@@ -148,19 +148,19 @@ describe('tooltip', function() {
     expect( elmBody.children().length ).toBe( 0 );
   }));
 
-  it('issue 1191 - isolate scope on the popup should always be child of correct element scope', function () {
+  it('issue 1191 - scope on the popup should always be child of correct element scope', function () {
     var ttScope;
     elm.trigger( 'mouseenter' );
 
-    ttScope = angular.element( elmBody.children()[1] ).isolateScope();
+    ttScope = angular.element( elmBody.children()[1] ).scope();
     expect( ttScope.$parent ).toBe( tooltipScope );
 
     elm.trigger( 'mouseleave' );
 
     // After leaving and coming back, the scope's parent should be the same
     elm.trigger( 'mouseenter' );
 
-    ttScope = angular.element( elmBody.children()[1] ).isolateScope();
+    ttScope = angular.element( elmBody.children()[1] ).scope();
     expect( ttScope.$parent ).toBe( tooltipScope );
 
     elm.trigger( 'mouseleave' );
@@ -349,7 +349,7 @@ describe('tooltip', function() {
       var match = false;
 
       angular.forEach(angular.element.cache, function (item) {
-        if (item.data && item.data.$isolateScope === tooltipScope) {
+        if (item.data && item.data.$scope === tooltipScope) {
           match = true;
         }
       });
@@ -369,7 +369,7 @@ describe('tooltip', function() {
       tooltipScope = elmScope.$$childTail.$$childTail;
     }));
 
-    it( 'should not contain a cached reference when visible', inject( function( $timeout ) {
+    it( 'should not contain a cached reference when not visible', inject( function( $timeout ) {
       expect( inCache() ).toBeTruthy();
       elmScope.$destroy();
       expect( inCache() ).toBeFalsy();

src/tooltip/tooltip.js

@@ -112,6 +112,7 @@ angular.module( 'ui.bootstrap.tooltip', [ 'ui.bootstrap.position', 'ui.bootstrap
 
           return function link ( scope, element, attrs ) {
             var tooltip;
+            var tooltipLinkedScope;
             var transitionTimeout;
             var popupTimeout;
             var appendToBody = angular.isDefined( options.appendToBody ) ? options.appendToBody : false;
@@ -234,7 +235,8 @@ angular.module( 'ui.bootstrap.tooltip', [ 'ui.bootstrap.position', 'ui.bootstrap
               if (tooltip) {
                 removeTooltip();
               }
-              tooltip = tooltipLinker(ttScope);
+              tooltipLinkedScope = ttScope.$new();
+              tooltip = tooltipLinker(tooltipLinkedScope);
             }
 
             function removeTooltip() {
@@ -243,6 +245,10 @@ angular.module( 'ui.bootstrap.tooltip', [ 'ui.bootstrap.position', 'ui.bootstrap
                 tooltip.remove();
                 tooltip = null;
               }
+              if (tooltipLinkedScope) {
+                tooltipLinkedScope.$destroy();
+                tooltipLinkedScope = null;
+              }
             }
 
             function prepareTooltip() {