decrementListenerCount: TypeError: Cannot read property '$destroy' of null

[ppawel]

With AngularJS v1.3.0-build.2533+sha.ff5cf73 I get the following in my application. It occurs during navigation, it looks as if Angular tries to destroy one of the scopes in my application twice.

TypeError: Cannot read property '$destroy' of null
    at decrementListenerCount (http://localhost:9000/bower_components/angular/angular.js:12686:32)
    at http://localhost:9000/bower_components/angular/angular.js:1012:18
    at forEach (http://localhost:9000/bower_components/angular/angular.js:330:20)
    at Scope.$destroy (http://localhost:9000/bower_components/angular/angular.js:12306:9)
    at HTMLDivElement.<anonymous> (http://localhost:9000/bower_components/angular/angular.js:1017:18)
    at HTMLDivElement.jQuery.event.dispatch (http://localhost:9000/bower_components/jquery/jquery.js:5095:9)
    at HTMLDivElement.elemData.handle (http://localhost:9000/bower_components/jquery/jquery.js:4766:28)
    at Object.jQuery.event.trigger (http://localhost:9000/bower_components/jquery/jquery.js:5007:12)
    at jQuery.fn.extend.triggerHandler (http://localhost:9000/bower_components/jquery/jquery.js:5697:24)
    at removePatch [as remove] (http://localhost:9000/bower_components/angular/angular.js:2213:21) angular.js:9735
(anonymous function) angular.js:9735
(anonymous function) angular.js:7169
Scope.$broadcast angular.js:12640
$state.transition.resolved.then.$state.transition angular-ui-router.js:2114
wrappedCallback angular.js:11272
(anonymous function) angular.js:11358
Scope.$eval angular.js:12359
Scope.$digest angular.js:12177
Scope.$apply angular.js:12463
(anonymous function) angular.js:9524
jQuery.event.dispatch jquery.js:5095
elemData.handle

Scope looks like this at this point:

ChildScope {$id: null, this: null, $$listeners: null, $$listenerCount: null, $parent: null…}
$$childHead: null
$$childTail: null
$$destroyed: true
$$listenerCount: null
$$listeners: null
$$nextSibling: null
$$prevSibling: null
$$watchers: null
$id: null
$parent: null
data: null
selectSection: null
selectTab: null
tabs: null
this: null

[Narretz]

Suspect: f552f25

[ppawel]

BTW it works with 1.2.15 and also I'm pretty sure that it worked with 1.3 at some point.

[Narretz]

Does it happen in FF and Chrome (or other browsers)?

[ppawel]

Happens on both Firefox 28 and Chromium 33.0.1750.152 (OS is Linux).

[Narretz]

Can you try with v1.3.0-build.2531+sha.ec8e395? If it doesn't happen there it's 50% in the commit I referenced. It'll also be helpful if you had a minimal reproduction.

[lgalfaso]

looking into this

[lgalfaso]

Ok, was able to reproduce this, there are a few small issues here:

• Trying to listen to an event on a child scope of an already destroyed scope throws
• Trying to deregister an event on a child scope of an already destroyed scope throws

[ppawel]

Just curious, shouldn't you fix the cause and not the symptoms here? I mean it looks like attempt to destroy a scope twice is the real bug here and not the exception which is just a symptom.

Anyway, I won't be able to prepare a minimal test case for this, best I can do is try different builds to help you bisect if needed.

[lgalfaso]

@ppawel a scope cannot be destroyed twice, the first check that is done on the $destroy method is that the scope is not destroyed. The issue is on the the event system when it tries to update the number of listeners for a particular event. There are several occasions when this can happens, when destroying a scope, when adding a listener or when removing a listener (in a strict sense, the case when removing a listener and destroying the scope is the same case).

The fact that you are seeing a scope that is destroyed, does not mean that this is the scope that we are attempting to destroy twice, but the fact that when some of the previous operations is performed on a child scope, it needs to modify the parent hierarchy.

[IgorMinar]

@jeffbcross this is related to the mem leak issue I'm dealing with, so I'll take over the ownership of this one.

[IgorMinar]

ok, I reverted the commit that introduced this. we still need some solution to deal with the V8 bug that the reverted commit worked around, but we need to do implement it better.

@lgalfaso I'm trying other strategies, but will keep your PR in mind in case I don't come up with another workaround.

[ppawel]

Just to confirm - it works for me now.

[e-oz]

I see this message in v1.3.0-build.3024+sha.60c13a1
code is pretty simple:

    $scope.$on('$destroy', function () {
      cancelComet = true;
    });

[yu521088]

I am still seeing this issue when doing like these:

• set title like below:

    <ion-nav-title ng-if="boolean">xxx</ion-nav-title>
    <ion-nav-title ng-if="!boolean">xxxxx</ion-nav-title>

• go to this page, and go back to parent view, this message will occur

here is the error message:

TypeError: Cannot read property '$destroy' of undefined
    at Object.IonicModule.controller.self.createHeaderBar.headerBarInstance.removeItem (ionic.bundle.js:47770)
    at Object.IonicModule.controller.self.createHeaderBar.headerBarInstance.setItem (ionic.bundle.js:47746)
    at ionic.bundle.js:47890
    at forEach (ionic.bundle.js:9150)
    at IonicModule.controller.self.update (ionic.bundle.js:47889)
    at IonicModule.controller.self.beforeEnter (ionic.bundle.js:48315)
    at IonicModule.controller.self.beforeEnter (ionic.bundle.js:50259)
    at Scope.$get.Scope.$emit (ionic.bundle.js:23474)
    at Object.IonicModule.factory.ionicViewSwitcher.create.switcher.emit (ionic.bundle.js:46814)
    at Object.IonicModule.factory.ionicViewSwitcher.create.switcher.transition (ionic.bundle.js:46672)