fix(ngModel): remove reference to parentForm from removed control

Otherwise, once the removed control's validity changes,
it will continue to be reflected on its former parent form.

Fixes angular#12263

Author: Narretz

Diff for: src/ng/directive/form.js

@@ -168,6 +168,7 @@ function FormController(element, attrs, $scope, $animate, $interpolate) {
     });
 
     arrayRemove(controls, control);
+    control.$$parentForm = nullFormCtrl;
   };
 
 

Diff for: src/ng/directive/ngModel.js

@@ -237,6 +237,7 @@ var NgModelController = ['$scope', '$exceptionHandler', '$attrs', '$element', '$
   this.$pending = undefined; // keep pending keys here
   this.$name = $interpolate($attr.name || '', false)($scope);
 
+  var parentForm = this.$$parentForm = $element.inheritedData('$formController') || nullFormCtrl
 
   var parsedNgModel = $parse($attr.ngModel),
       parsedNgModelAssign = parsedNgModel.assign,
@@ -316,8 +317,7 @@ var NgModelController = ['$scope', '$exceptionHandler', '$attrs', '$element', '$
     return isUndefined(value) || value === '' || value === null || value !== value;
   };
 
-  var parentForm = $element.inheritedData('$formController') || nullFormCtrl,
-      currentValidationRunId = 0;
+  var currentValidationRunId = 0;
 
   /**
    * @ngdoc method
@@ -350,7 +350,6 @@ var NgModelController = ['$scope', '$exceptionHandler', '$attrs', '$element', '$
     unset: function(object, property) {
       delete object[property];
     },
-    parentForm: parentForm,
     $animate: $animate
   });
 
@@ -1258,7 +1257,6 @@ function addSetValidityMethod(context) {
       classCache = {},
       set = context.set,
       unset = context.unset,
-      parentForm = context.parentForm,
       $animate = context.$animate;
 
   classCache[INVALID_CLASS] = !(classCache[VALID_CLASS] = $element.hasClass(VALID_CLASS));
@@ -1310,7 +1308,7 @@ function addSetValidityMethod(context) {
     }
 
     toggleValidationCss(validationErrorKey, combinedState);
-    parentForm.$setValidity(validationErrorKey, combinedState, ctrl);
+    ctrl.$$parentForm.$setValidity(validationErrorKey, combinedState, ctrl);
   }
 
   function createAndSet(name, value, controller) {

Diff for: test/ng/directive/formSpec.js

@@ -58,6 +58,50 @@ describe('form', function() {
     expect(form.alias).toBeUndefined();
   });
 
+  it('should ignore the validity of removed form control references', function() {
+    doc = $compile(
+      '<form name="myForm">' +
+        '<input name="control" ng-maxlength="1" ng-model="value" store-model-ctrl/>' +
+        '<ng-form name="childform">' +
+          '<input name="childformcontrol" ng-maxlength="1" ng-model="value"/>' +
+        '</ng-form>' +
+      '</form>')(scope);
+
+    var form = scope.myForm;
+    var childformController = doc.find('ng-form').eq(0).controller('form');
+
+    var input = doc.find('input').eq(0);
+    var childforminput = doc.find('input').eq(1);
+
+    changeInputValue(input, 'ab');
+    changeInputValue(childforminput, 'ab');
+    scope.$apply();
+
+    expect(form.$error.maxlength).toBeTruthy();
+    expect(form.$error.maxlength[0].$name).toBe('control');
+    expect(form.$error.maxlength[1].$name).toBe('childform');
+
+    // remove child form
+    form.$removeControl(childformController);
+    expect(form.childform).toBeUndefined();
+
+    expect(form.$error.maxlength.length).toBe(1);
+    expect(form.$error.maxlength[0].$name).toBe('control');
+
+    // remove control
+    form.$removeControl(form.control);
+    expect(form.control).toBeUndefined();
+
+    expect(form.$error.maxlength).toBeFalsy();
+
+    changeInputValue(input, 'abc');
+    changeInputValue(childforminput, 'abc');
+    scope.$apply();
+
+    expect(form.$error.maxlength).toBeFalsy();
+  });
+
+
   it('should remove scope reference when form with no parent form is removed from the DOM', function() {
     var formController;
     scope.ctrl = {};