feat(form): support dynamic form validation

Author: caitp

src/ng/directive/form.js

@@ -52,8 +52,8 @@ 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 = [];
@@ -62,7 +62,7 @@ function FormController(element, attrs, $scope, $animate) {
   form.$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;
@@ -485,10 +485,21 @@ var formDirectiveFactory = function(isNgForm) {
             }
 
             var parentFormCtrl = formElement.parent().controller('form'),
-                alias = attr.name || attr.ngForm;
+                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);
+                if (parentFormCtrl) {
+                  parentFormCtrl.$$renameControl(controller, alias);
+                } else {
+                  controller.$name = alias;
+                }
+              });
             }
             if (parentFormCtrl) {
               formElement.on('$destroy', function() {

test/ng/directive/formSpec.js

@@ -782,6 +782,40 @@ 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.$digest();
+
+    expect(scope.form.nestedA).toBeUndefined();
+    expect(scope.form.nestedB).toBe(formA);
+    expect(formA.nestedX).toBeUndefined();
+    expect(formA.nestedY).toBe(formX);
+  });
+
+
   describe('$setSubmitted', function() {
     beforeEach(function() {
       doc = $compile(