fix(ngEventDirs): execute blur and focus expression using scope.$evalAsync

BREAKING CHANGE:
The `blur` and `focus` event fire synchronously, also during DOM operations
that remove elements. This lead to errors as the Angular model was not
in a consistent state. See this [fiddle](http://jsfiddle.net/fq1dq5yb/) for a demo.

This change executes the expression of those events using
`scope.$evalAsync` if an `$apply` is in progress, otherwise
keeps the old behavior.

Fixes #4979
Fixes #5945
Closes #8803
Closes #6910
Closes #5402

Author: tbosch

src/ng/directive/ngEventDirs.js

@@ -37,6 +37,14 @@
  * Events that are handled via these handler are always configured not to propagate further.
  */
 var ngEventDirectives = {};
+
+// For events that might fire synchronously during DOM manipulation
+// we need to execute their event handlers asynchronously using $evalAsync,
+// so that they are not executed in an inconsistent state.
+var forceAsyncEvents = {
+  'blur': true,
+  'focus': true
+};
 forEach(
   'click dblclick mousedown mouseup mouseover mouseout mousemove mouseenter mouseleave keydown keyup keypress submit focus blur copy cut paste'.split(' '),
   function(name) {
@@ -46,10 +54,16 @@ forEach(
         compile: function($element, attr) {
           var fn = $parse(attr[directiveName]);
           return function ngEventHandler(scope, element) {
-            element.on(lowercase(name), function(event) {
-              scope.$apply(function() {
+            var eventName = lowercase(name);
+            element.on(eventName, function(event) {
+              var callback = function() {
                 fn(scope, {$event:event});
-              });
+              };
+              if (forceAsyncEvents[eventName] && scope.$$phase) {
+                scope.$evalAsync(callback);
+              } else {
+                scope.$apply(callback);
+              }
             });
           };
         }
@@ -366,6 +380,10 @@ forEach(
  * @description
  * Specify custom behavior on focus event.
  *
+ * Note: As the `focus` event is executed synchronously when calling `input.focus()`
+ * AngularJS executes the expression using `scope.$evalAsync` if the event is fired
+ * during an `$apply` to ensure a consistent state.
+ *
  * @element window, input, select, textarea, a
  * @priority 0
  * @param {expression} ngFocus {@link guide/expression Expression} to evaluate upon
@@ -382,6 +400,11 @@ forEach(
  * @description
  * Specify custom behavior on blur event.
  *
+ * Note: As the `blur` event is executed synchronously also during DOM manipulations
+ * (e.g. removing a focussed input),
+ * AngularJS executes the expression using `scope.$evalAsync` if the event is fired
+ * during an `$apply` to ensure a consistent state.
+ *
  * @element window, input, select, textarea, a
  * @priority 0
  * @param {expression} ngBlur {@link guide/expression Expression} to evaluate upon

test/ng/directive/ngEventDirsSpec.js

@@ -39,4 +39,64 @@ describe('event directives', function() {
       expect($rootScope.formSubmitted).toEqual('foo');
     }));
   });
+
+  describe('focus', function() {
+
+    it('should call the listener asynchronously during $apply',
+        inject(function($rootScope, $compile) {
+      element = $compile('<input type="text" ng-focus="focus()">')($rootScope);
+      $rootScope.focus = jasmine.createSpy('focus');
+
+      $rootScope.$apply(function() {
+        element.triggerHandler('focus');
+        expect($rootScope.focus).not.toHaveBeenCalled();
+      });
+
+      expect($rootScope.focus).toHaveBeenCalledOnce();
+    }));
+
+    it('should call the listener synchronously inside of $apply if outside of $apply',
+        inject(function($rootScope, $compile) {
+      element = $compile('<input type="text" ng-focus="focus()" ng-model="value">')($rootScope);
+      $rootScope.focus = jasmine.createSpy('focus').andCallFake(function() {
+        $rootScope.value = 'newValue';
+      });
+
+      element.triggerHandler('focus');
+
+      expect($rootScope.focus).toHaveBeenCalledOnce();
+      expect(element.val()).toBe('newValue');
+    }));
+
+  });
+
+  describe('blur', function() {
+
+    it('should call the listener asynchronously during $apply',
+        inject(function($rootScope, $compile) {
+      element = $compile('<input type="text" ng-blur="blur()">')($rootScope);
+      $rootScope.blur = jasmine.createSpy('blur');
+
+      $rootScope.$apply(function() {
+        element.triggerHandler('blur');
+        expect($rootScope.blur).not.toHaveBeenCalled();
+      });
+
+      expect($rootScope.blur).toHaveBeenCalledOnce();
+    }));
+
+    it('should call the listener synchronously inside of $apply if outside of $apply',
+        inject(function($rootScope, $compile) {
+      element = $compile('<input type="text" ng-blur="blur()" ng-model="value">')($rootScope);
+      $rootScope.blur = jasmine.createSpy('blur').andCallFake(function() {
+        $rootScope.value = 'newValue';
+      });
+
+      element.triggerHandler('blur');
+
+      expect($rootScope.blur).toHaveBeenCalledOnce();
+      expect(element.val()).toBe('newValue');
+    }));
+
+  });
 });

test/ng/directive/ngKeySpec.js

@@ -34,23 +34,5 @@ describe('ngKeyup and ngKeydown directives', function() {
     expect($rootScope.touched).toEqual(true);
   }));
 
-  it('should get called on focus', inject(function($rootScope, $compile) {
-    element = $compile('<input ng-focus="touched = true">')($rootScope);
-    $rootScope.$digest();
-    expect($rootScope.touched).toBeFalsy();
-
-    browserTrigger(element, 'focus');
-    expect($rootScope.touched).toEqual(true);
-  }));
-
-  it('should get called on blur', inject(function($rootScope, $compile) {
-    element = $compile('<input ng-blur="touched = true">')($rootScope);
-    $rootScope.$digest();
-    expect($rootScope.touched).toBeFalsy();
-
-    browserTrigger(element, 'blur');
-    expect($rootScope.touched).toEqual(true);
-  }));
-
 });