fix(ngModel): allow non-assignable binding when getterSetter is used

Closes #8704

src/ng/directive/input.js

@@ -1599,10 +1599,14 @@ var NgModelController = ['$scope', '$exceptionHandler', '$attrs', '$element', '$
       pendingDebounce = null,
       ctrl = this;
 
-  if (!ngModelSet) {
-    throw $ngModelMinErr('nonassign', "Expression '{0}' is non-assignable. Element: {1}",
-        $attr.ngModel, startingTag($element));
-  }
+  this.$$setOptions = function(options) {
+    ctrl.$options = options;
+
+    if (!ngModelSet && (!options || !options.getterSetter)) {
+      throw $ngModelMinErr('nonassign', "Expression '{0}' is non-assignable. Element: {1}",
+          $attr.ngModel, startingTag($element));
+    }
+  };
 
   /**
    * @ngdoc method
@@ -2293,16 +2297,12 @@ var ngModelDirective = function() {
     controller: NgModelController,
     link: {
       pre: function(scope, element, attr, ctrls) {
-        // Pass the ng-model-options to the ng-model controller
-        if (ctrls[2]) {
-          ctrls[0].$options = ctrls[2].$options;
-        }
-
-        // notify others, especially parent forms
-
         var modelCtrl = ctrls[0],
             formCtrl = ctrls[1] || nullFormCtrl;
 
+        modelCtrl.$$setOptions(ctrls[2] && ctrls[2].$options);
+
+        // notify others, especially parent forms
         formCtrl.$addControl(modelCtrl);
 
         scope.$on('$destroy', function() {

test/ng/directive/inputSpec.js

@@ -32,26 +32,6 @@ describe('NgModelController', function() {
   });
 
 
-  it('should fail on non-assignable model binding', inject(function($controller) {
-    var exception;
-
-    try {
-      $controller(NgModelController, {
-        $scope: null,
-        $element: jqLite('<input ng-model="1+2">'),
-        $attrs: {
-          ngModel: '1+2'
-        }
-      });
-    } catch (e) {
-      exception = e;
-    }
-
-    expect(exception.message).
-        toMatch(/^\[ngModel:nonassign\] Expression '1\+2' is non\-assignable\. Element: <input( value="")? ng-model="1\+2">/);
-  }));
-
-
   it('should init the properties', function() {
     expect(ctrl.$untouched).toBe(true);
     expect(ctrl.$touched).toBe(false);
@@ -1581,6 +1561,18 @@ describe('input', function() {
       expect(scope.name).toBe('d');
     });
 
+    it('should fail on non-assignable model binding if getterSetter is false', function() {
+      expect(function() {
+        compileInput('<input type="text" ng-model="accessor(user, \'name\')" />');
+      }).toThrowMinErr('ngModel', 'nonassign', 'Expression \'accessor(user, \'name\')\' is non-assignable.');
+    });
+
+    it('should not fail on non-assignable model binding if getterSetter is true', function() {
+      compileInput(
+        '<input type="text" ng-model="accessor(user, \'name\')" '+
+          'ng-model-options="{ getterSetter: true }" />');
+    });
+
   });
 
   it('should allow complex reference binding', function() {