Memory leak with $setValidity

[dlongley]

If ng-model is used within a form and toggled with ng-if and $setValidity is called on the ngModelController, then a memory leak occurs.

Specifically, the $setValidity call in ngModel (line 3172) adds a validity entry to the parent form controller that keeps a reference to the ngModelController. There's nothing in place to remove this entry if that controller gets destroyed, so these references stick around. Worse, the $setValidity call is added to the ngModelController by creating a closure that wraps the ngModel's element, which can result in leaking quite a bit of memory in complex applications.

This plunker demonstrates the issue by printing out the number of ngModelController references maintained by the form controller each time you toggle a form input off/on.

[pkozlowski-opensource]

Oh, this sounds bad. We need to fix it in the next patch release.

[manikantag]

Now that new versions of input.js file doesn't have 3172 line, correct line number referred by @dlongley is in v1.3.7: https://github.com/angular/angular.js/blob/v1.3.7/src/ng/directive/input.js#L3172