FIX: VirtualPage not using target page's template (fixes #2039) (#2041)

* FIX: VirtualPage refreshFromCopied creates duplicate URLSegments on first write

* FIX: VirtualPage not using target page's template (fixes #2039)

code/Controllers/ContentController.php

@@ -440,16 +440,24 @@ HTML;
             $action = '_' . $action;
         }
 
-        $templates = array_merge(
+        $templatesFound = [];
-            // Find templates by dataRecord
+        // Find templates for the record + action together - e.g. Page_action.ss
-            SSViewer::get_templates_by_class(get_class($this->dataRecord), $action, "SilverStripe\\CMS\\Model\\SiteTree"),
+        if ($this->dataRecord instanceof SiteTree) {
-            // Next, we need to add templates for all controllers
+            $templatesFound[] = $this->dataRecord->getViewerTemplates($action);
-            SSViewer::get_templates_by_class(static::class, $action, "SilverStripe\\Control\\Controller"),
+        }
-            // Fail-over to the same for the "index" action
-            SSViewer::get_templates_by_class(get_class($this->dataRecord), "", "SilverStripe\\CMS\\Model\\SiteTree"),
-            SSViewer::get_templates_by_class(static::class, "", "SilverStripe\\Control\\Controller")
-        );
 
+        // Find templates for the controller + action together - e.g. PageController_action.ss
+        $templatesFound[] = SSViewer::get_templates_by_class(static::class, $action, Controller::class);
+
+        // Find templates for the record without an action - e.g. Page.ss
+        if ($this->dataRecord instanceof SiteTree) {
+            $templatesFound[] = $this->dataRecord->getViewerTemplates();
+        }
+
+        // Find the templates for the controller without an action - e.g. PageController.ss
+        $templatesFound[] = SSViewer::get_templates_by_class(static::class, "", Controller::class);
+
+        $templates = array_merge(...$templatesFound);
         return SSViewer::create($templates);
     }
 

code/Model/VirtualPage.php

@@ -2,6 +2,7 @@
 
 namespace SilverStripe\CMS\Model;
 
+use Page;
 use SilverStripe\Core\Convert;
 use SilverStripe\Forms\FieldList;
 use SilverStripe\Forms\LiteralField;
@@ -9,9 +10,9 @@ use SilverStripe\Forms\ReadonlyTransformation;
 use SilverStripe\Forms\TreeDropdownField;
 use SilverStripe\ORM\DataObject;
 use SilverStripe\ORM\ValidationResult;
-use SilverStripe\Versioned\Versioned;
 use SilverStripe\Security\Member;
-use Page;
+use SilverStripe\Versioned\Versioned;
+use SilverStripe\View\SSViewer;
 
 /**
  * Virtual Page creates an instance of a  page, with the same fields that the original page had, but readonly.
@@ -277,8 +278,8 @@ class VirtualPage extends Page
 
     public function onBeforeWrite()
     {
-        parent::onBeforeWrite();
         $this->refreshFromCopied();
+        parent::onBeforeWrite();
     }
 
     /**
@@ -368,6 +369,22 @@ class VirtualPage extends Page
         return parent::CMSTreeClasses() . ' VirtualPage-' . $this->CopyContentFrom()->ClassName;
     }
 
+    /**
+     * Use the target page's class name for fetching templates - as we need to take on its appearance
+     *
+     * @param string $suffix
+     * @return array
+     */
+    public function getViewerTemplates($suffix = '')
+    {
+        $copy = $this->CopyContentFrom();
+        if ($copy && $copy->exists()) {
+            return $copy->getViewerTemplates($suffix);
+        }
+
+        return parent::getViewerTemplates($suffix);
+    }
+
     /**
      * Allow attributes on the master page to pass
      * through to the virtual page

tests/php/Model/VirtualPageTest.php

@@ -632,6 +632,18 @@ class VirtualPageTest extends FunctionalTest
             $this->assertEquals(200, $response->getStatusCode());
             $this->assertContains('TestContent', $response->getBody());
             $this->assertNotContains('NotThisContent', $response->getBody());
+
+            // VirtualPageTest_ClassB doesn't have an associated controller for
+            // ModelAsController::controller_for() to find
+            $page = new VirtualPageTest_ClassB();
+            $page->Title = 'Test Page B';
+            $page->write();
+            $vp = new VirtualPage();
+            $vp->CopyContentFromID = $page->ID;
+            $vp->write();
+            $response = $this->get($vp->Link());
+            $this->assertEquals(200, $response->getStatusCode());
+            $this->assertContains('Test Page B', $response->getBody());
         });
     }
 

tests/php/Model/themes/virtualpagetest/templates/SilverStripe/CMS/Tests/Model/VirtualPageTest_ClassB.ss

@@ -0,0 +1 @@
+<div>$Title</div>