add controller_name config var to SiteTree for easier override

code/Model/SiteTree.php

@@ -185,6 +185,15 @@ class SiteTree extends DataObject implements PermissionProvider, i18nEntityProvi
      */
     private static $hide_ancestor = null;
 
+    /**
+     * You can define the class of the controller that maps to your SiteTree object here if
+     * you don't want to rely on the magic of appending Controller to the Classname
+     *
+     * @config
+     * @var string
+     */
+    private static $controller_name = null;
+
     private static $db = array(
         "URLSegment" => "Varchar(255)",
         "Title" => "Varchar(255)",
@@ -2763,11 +2772,16 @@ class SiteTree extends DataObject implements PermissionProvider, i18nEntityProvi
 
     /**
      * Find the controller name by our convention of {$ModelClass}Controller
+     * Can be overriden by config variable
      *
      * @return string
      */
     public function getControllerName()
     {
+        if ($controller = Config::inst()->get(static::class, 'controller_name')) {
+            return $controller;
+        }
+
         //default controller for SiteTree objects
         $controller = ContentController::class;
 

tests/php/Model/SiteTreeTest.php

@@ -1504,6 +1504,16 @@ class SiteTreeTest extends SapphireTest
         $this->assertSame('PageController', $class->getControllerName());
     }
 
+    /**
+     * Test that the controller name for a SiteTree instance can be gathered when set directly via config var
+     */
+    public function testGetControllerNameFromConfig()
+    {
+        Config::inst()->update(Page::class, 'controller_name', 'This\\Is\\A\\New\\Controller');
+        $class = new Page;
+        $this->assertSame('This\\Is\\A\\New\\Controller', $class->getControllerName());
+    }
+
     /**
      * Test that underscored class names (legacy) are still supported (deprecation notice is issued though).
      */