fix(ngOptions): don't throw if options are unset inside writeValue

This can happen in the following case:
- there's a blank option inside the select
- another directive on the select element compiles the contents of it before ngOptions is linked.

Now this happens:
- the option directive is compiled and adds an element $destroy listener that calls ngModel.$render
- when ngOptions processes the blank option, it removes the element, and
triggers the $destroy listener
- ngModel.$render delegates to selectCtrl.writeValue, which accesses the options
- in that phase, the options aren't yet set

Fixes angular#11685

Author: Narretz

src/ng/directive/ngOptions.js

@@ -453,7 +453,7 @@ var ngOptionsDirective = ['$compile', '$parse', function($compile, $parse) {
       if (!multiple) {
 
         selectCtrl.writeValue = function writeNgOptionsValue(value) {
-          var option = options.getOptionFromViewValue(value);
+          var option = options && options.getOptionFromViewValue(value);
 
           if (option && !option.disabled) {
             if (selectElement[0].value !== option.selectValue) {

test/ng/directive/ngOptionsSpec.js

@@ -104,6 +104,17 @@ describe('ngOptions', function() {
     });
   });
 
+  beforeEach(module(function($compileProvider) {
+    $compileProvider
+      .directive('compileContents', function($compile) {
+        return {
+          link: function(scope, element) {
+            $compile(element.contents())(scope);
+          }
+        };
+    });
+  }));
+
   beforeEach(inject(function($rootScope, _$compile_) {
     scope = $rootScope.$new(); //create a child scope because the root scope can't be $destroy-ed
     $compile = _$compile_;
@@ -2119,6 +2130,18 @@ describe('ngOptions', function() {
       option = element.find('option').eq(0);
       expect(option.text()).toBe('A');
     });
+
+
+    it('should not throw when a directive compiles the blank option before ngOptions is linked', function() {
+      expect(function() {
+          createSelect({
+          'compile-contents': '',
+          'name': 'select',
+          'ng-model': 'value',
+          'ng-options': 'item for item in items',
+        }, true);
+      }).not.toThrow();
+    });
   });