ENH Update code to reflect changes in silverstripe/cms

src/Forms/GridFieldSiteTreeAddNewButton.php

@@ -2,10 +2,11 @@
 
 namespace SilverStripe\Lumberjack\Forms;
 
-use SilverStripe\CMS\Controllers\CMSPageAddController;
+use SilverStripe\CMS\Controllers\CMSMain;
 use SilverStripe\CMS\Model\SiteTree;
 use SilverStripe\Control\Controller;
 use SilverStripe\Control\HTTPResponse;
+use SilverStripe\Core\ClassInfo;
 use SilverStripe\Core\Config\Config;
 use SilverStripe\Core\Injector\Injector;
 use SilverStripe\Forms\DropdownField;
@@ -42,7 +43,8 @@ public function getAllowedChildren(SiteTree $parent = null)
             return array();
         }
 
-        $nonHiddenPageTypes = SiteTree::page_type_classes();
+        $nonHiddenPageTypes = ClassInfo::getValidSubClasses(SiteTree::class);
+        SiteTree::singleton()->updateAllowedSubClasses($nonHiddenPageTypes);
         $allowedChildren = $parent->allowedChildren();
         $children = array();
         foreach ($allowedChildren as $class) {
@@ -131,7 +133,7 @@ public function getActions($gridField)
     }
 
     /**
-     * Handles the add action, but only acts as a wrapper for {@link CMSPageAddController::doAdd()}
+     * Handles the add action, but only acts as a wrapper for CMSMain
      *
      * @param GridField $gridField
      * @param string $actionName
@@ -151,16 +153,16 @@ public function handleAction(GridField $gridField, $actionName, $arguments, $dat
                 'PageType' => $tmpData['pageType']
             );
 
-            $controller = Injector::inst()->create(CMSPageAddController::class);
+            $controller = Injector::inst()->create(CMSMain::class);
+            $form = $controller->AddForm();
 
-            // pass current request to newly created controller
+            // pass current request down in case either of these needs it
             $request = Controller::curr()->getRequest();
             $controller->setRequest($request);
+            $form->getRequestHandler()->setRequest($request);
 
-            $form = $controller->AddForm();
             $form->loadDataFrom($data);
-
-            return $controller->doAdd($data, $form);
+            return $form->doAdd($data, $form);
         }
 
         return null;