feat(input): support dynamic element validation

Interpolates the form and form control attribute name, so that dynamic form controls (such as those
rendered in an ngRepeat) will always have their expected interpolated name.

The control will be present in its parent form controller with the interpolated property name, and
this name can change when the interpolated value changes.

Closes #4791
Closes #1404

src/ng/directive/form.js

@@ -4,6 +4,7 @@
  */
 var nullFormCtrl = {
   $addControl: noop,
+  $$renameControl: nullFormRenameControl,
   $removeControl: noop,
   $setValidity: noop,
   $$setPending: noop,
@@ -14,6 +15,10 @@ var nullFormCtrl = {
 },
 SUBMITTED_CLASS = 'ng-submitted';
 
+function nullFormRenameControl(control, name) {
+  control.$name = name;
+}
+
 /**
  * @ngdoc type
  * @name form.FormController
@@ -51,17 +56,18 @@ SUBMITTED_CLASS = 'ng-submitted';
  *
  */
 //asks for $scope to fool the BC controller module
-FormController.$inject = ['$element', '$attrs', '$scope', '$animate'];
-function FormController(element, attrs, $scope, $animate) {
+FormController.$inject = ['$element', '$attrs', '$scope', '$animate', '$interpolate'];
+function FormController(element, attrs, $scope, $animate, $interpolate) {
   var form = this,
-      parentForm = element.parent().controller('form') || nullFormCtrl,
       controls = [];
 
+  var parentForm = form.$$parentForm = element.parent().controller('form') || nullFormCtrl;
+
   // init state
   form.$error = {};
   form.$$success = {};
   form.$pending = undefined;
-  form.$name = attrs.name || attrs.ngForm;
+  form.$name = $interpolate(attrs.name || attrs.ngForm || '')($scope);
   form.$dirty = false;
   form.$pristine = true;
   form.$valid = true;
@@ -127,6 +133,17 @@ function FormController(element, attrs, $scope, $animate) {
     }
   };
 
+  // Private API: rename a form control
+  form.$$renameControl = function(control, newName) {
+    var oldName = control.$name;
+
+    if (form[oldName] === control) {
+      delete form[oldName];
+    }
+    form[newName] = control;
+    control.$name = newName;
+  };
+
   /**
    * @ngdoc method
    * @name form.FormController#$removeControl
@@ -466,13 +483,20 @@ var formDirectiveFactory = function(isNgForm) {
               });
             }
 
-            var parentFormCtrl = formElement.parent().controller('form'),
-                alias = attr.name || attr.ngForm;
+            var parentFormCtrl = controller.$$parentForm,
+                alias = controller.$name;
 
             if (alias) {
               setter(scope, alias, controller, alias);
+              attr.$observe(attr.name ? 'name' : 'ngForm', function(newValue) {
+                if (alias === newValue) return;
+                setter(scope, alias, undefined, alias);
+                alias = newValue;
+                setter(scope, alias, controller, alias);
+                parentFormCtrl.$$renameControl(controller, alias);
+              });
             }
-            if (parentFormCtrl) {
+            if (parentFormCtrl !== nullFormCtrl) {
               formElement.on('$destroy', function() {
                 parentFormCtrl.$removeControl(controller);
                 if (alias) {

src/ng/directive/input.js

@@ -1657,8 +1657,8 @@ var VALID_CLASS = 'ng-valid',
  *
  *
  */
-var NgModelController = ['$scope', '$exceptionHandler', '$attrs', '$element', '$parse', '$animate', '$timeout', '$rootScope', '$q',
-    function($scope, $exceptionHandler, $attr, $element, $parse, $animate, $timeout, $rootScope, $q) {
+var NgModelController = ['$scope', '$exceptionHandler', '$attrs', '$element', '$parse', '$animate', '$timeout', '$rootScope', '$q', '$interpolate',
+    function($scope, $exceptionHandler, $attr, $element, $parse, $animate, $timeout, $rootScope, $q, $interpolate) {
   this.$viewValue = Number.NaN;
   this.$modelValue = Number.NaN;
   this.$validators = {};
@@ -1675,7 +1675,7 @@ var NgModelController = ['$scope', '$exceptionHandler', '$attrs', '$element', '$
   this.$error = {}; // keep invalid keys here
   this.$$success = {}; // keep valid keys here
   this.$pending = undefined; // keep pending keys here
-  this.$name = $attr.name;
+  this.$name = $interpolate($attr.name || '', false)($scope);
 
 
   var parsedNgModel = $parse($attr.ngModel),
@@ -2387,6 +2387,12 @@ var ngModelDirective = function() {
         // notify others, especially parent forms
         formCtrl.$addControl(modelCtrl);
 
+        attr.$observe('name', function(newValue) {
+          if (modelCtrl.$name !== newValue) {
+            formCtrl.$$renameControl(modelCtrl, newValue);
+          }
+        });
+
         scope.$on('$destroy', function() {
           formCtrl.$removeControl(modelCtrl);
         });

test/ng/directive/formSpec.js

@@ -782,6 +782,57 @@ describe('form', function() {
     });
   });
 
+
+  it('should rename nested form controls when interpolated name changes', function() {
+    scope.idA = 'A';
+    scope.idB = 'X';
+
+    doc = $compile(
+      '<form name="form">' +
+        '<div ng-form="nested{{idA}}">' +
+          '<div ng-form name="nested{{idB}}"' +
+          '</div>' +
+        '</div>' +
+      '</form'
+    )(scope);
+
+    scope.$digest();
+    var formA = scope.form.nestedA;
+    expect(formA).toBeDefined();
+    expect(formA.$name).toBe('nestedA');
+
+    var formX = formA.nestedX;
+    expect(formX).toBeDefined();
+    expect(formX.$name).toBe('nestedX');
+
+    scope.idA = 'B';
+    scope.idB = 'Y';
+    scope.$digest();
+
+    expect(scope.form.nestedA).toBeUndefined();
+    expect(scope.form.nestedB).toBe(formA);
+    expect(formA.nestedX).toBeUndefined();
+    expect(formA.nestedY).toBe(formX);
+  });
+
+
+  it('should rename forms with no parent when interpolated name changes', function() {
+    var element = $compile('<form name="name{{nameID}}"></form>')(scope);
+    var element2 = $compile('<div ng-form="name{{nameID}}"></div>')(scope);
+    scope.nameID = "A";
+    scope.$digest();
+    var form = element.controller('form');
+    var form2 = element2.controller('form');
+    expect(form.$name).toBe('nameA');
+    expect(form2.$name).toBe('nameA');
+
+    scope.nameID = "B";
+    scope.$digest();
+    expect(form.$name).toBe('nameB');
+    expect(form2.$name).toBe('nameB');
+  });
+
+
   describe('$setSubmitted', function() {
     beforeEach(function() {
       doc = $compile(

test/ng/directive/inputSpec.js

@@ -1289,6 +1289,42 @@ describe('input', function() {
     }
   }));
 
+
+  it('should interpolate input names', function() {
+    scope.nameID = '47';
+    compileInput('<input type="text" ng-model="name" name="name{{nameID}}" />');
+    expect(scope.form.name47.$pristine).toBeTruthy();
+    changeInputValueTo('caitp');
+    expect(scope.form.name47.$dirty).toBeTruthy();
+  });
+
+
+  it('should rename form controls in form when interpolated name changes', function() {
+    scope.nameID = "A";
+    compileInput('<input type="text" ng-model="name" name="name{{nameID}}" />');
+    expect(scope.form.nameA.$name).toBe('nameA');
+    var oldModel = scope.form.nameA;
+    scope.nameID = "B";
+    scope.$digest();
+    expect(scope.form.nameA).toBeUndefined();
+    expect(scope.form.nameB).toBe(oldModel);
+    expect(scope.form.nameB.$name).toBe('nameB');
+  });
+
+
+  it('should rename form controls in null form when interpolated name changes', function() {
+    var element = $compile('<input type="text" ng-model="name" name="name{{nameID}}" />')(scope);
+    scope.nameID = "A";
+    scope.$digest();
+    var model = element.controller('ngModel');
+    expect(model.$name).toBe('nameA');
+
+    scope.nameID = "B";
+    scope.$digest();
+    expect(model.$name).toBe('nameB');
+  });
+
+
   describe('"change" event', function() {
     function assertBrowserSupportsChangeEvent(inputEventSupported) {
       // Force browser to report a lack of an 'input' event

test/ng/directive/selectSpec.js

@@ -148,6 +148,33 @@ describe('select', function() {
     });
 
 
+    it('should interpolate select names', function() {
+      scope.robots = ['c3p0', 'r2d2'];
+      scope.name = 'r2d2';
+      scope.nameID = 47;
+      compile('<select ng-model="name" name="name{{nameID}}">' +
+                '<option ng-repeat="r in robots">{{r}}</option>' +
+              '</select>');
+      expect(scope.form.name47.$pristine).toBeTruthy();
+      browserTrigger(element.find('option').eq(0));
+      expect(scope.form.name47.$dirty).toBeTruthy();
+      expect(scope.name).toBe('c3p0');
+    });
+
+
+    it('should rename select controls in form when interpolated name changes', function() {
+      scope.nameID = "A";
+      compile('<select ng-model="name" name="name{{nameID}}"></select>');
+      expect(scope.form.nameA.$name).toBe('nameA');
+      var oldModel = scope.form.nameA;
+      scope.nameID = "B";
+      scope.$digest();
+      expect(scope.form.nameA).toBeUndefined();
+      expect(scope.form.nameB).toBe(oldModel);
+      expect(scope.form.nameB.$name).toBe('nameB');
+    });
+
+
     describe('empty option', function() {
 
       it('should select the empty option when model is undefined', function() {