Issue #2569083 by dsnopek, tim.plunkett, Wim Leers: Allow passing cacheable metadata to display variants (to enable Panels Everywhere)

core/lib/Drupal/Core/Display/VariantBase.php

@@ -7,6 +7,7 @@
 
 namespace Drupal\Core\Display;
 
+use Drupal\Core\Cache\RefinableCacheableDependencyTrait;
 use Drupal\Core\Form\FormStateInterface;
 use Drupal\Core\Plugin\PluginBase;
 use Drupal\Core\Plugin\PluginDependencyTrait;
@@ -23,6 +24,7 @@ use Drupal\Core\Session\AccountInterface;
 abstract class VariantBase extends PluginBase implements VariantInterface {
 
   use PluginDependencyTrait;
+  use RefinableCacheableDependencyTrait;
 
   /**
    * {@inheritdoc}

core/lib/Drupal/Core/Display/VariantInterface.php

@@ -9,6 +9,7 @@ namespace Drupal\Core\Display;
 
 use Drupal\Component\Plugin\ConfigurablePluginInterface;
 use Drupal\Component\Plugin\PluginInspectionInterface;
+use Drupal\Core\Cache\RefinableCacheableDependencyInterface;
 use Drupal\Core\Plugin\PluginFormInterface;
 use Drupal\Core\Session\AccountInterface;
 
@@ -20,7 +21,7 @@ use Drupal\Core\Session\AccountInterface;
  * @see \Drupal\Core\Display\VariantManager
  * @see plugin_api
  */
-interface VariantInterface extends PluginInspectionInterface, ConfigurablePluginInterface, PluginFormInterface {
+interface VariantInterface extends PluginInspectionInterface, ConfigurablePluginInterface, PluginFormInterface, RefinableCacheableDependencyInterface {
 
   /**
    * Returns the user-facing display variant label.
@@ -79,6 +80,10 @@ interface VariantInterface extends PluginInspectionInterface, ConfigurablePlugin
   /**
    * Builds and returns the renderable array for the display variant.
    *
+   * The variant can contain cacheability metadata for the configuration that
+   * was passed in setConfiguration(). In the build() method, this should be
+   * added to the render array that is returned.
+   *
    * @return array
    *   A render array for the display variant.
    */

core/lib/Drupal/Core/Render/MainContent/HtmlRenderer.php

@@ -236,6 +236,7 @@ class HtmlRenderer implements MainContentRendererInterface {
       }
       $page_display
         ->setMainContent($main_content)
+        ->addCacheableDependency($event)
         ->setConfiguration($event->getPluginConfiguration());
       // Some display variants need to be passed an array of contexts with
       // values because they can't get all their contexts globally. For example,

core/lib/Drupal/Core/Render/PageDisplayVariantSelectionEvent.php

@@ -7,6 +7,8 @@
 
 namespace Drupal\Core\Render;
 
+use Drupal\Core\Cache\RefinableCacheableDependencyInterface;
+use Drupal\Core\Cache\RefinableCacheableDependencyTrait;
 use Drupal\Core\Routing\RouteMatchInterface;
 use Symfony\Component\EventDispatcher\Event;
 
@@ -17,11 +19,14 @@ use Symfony\Component\EventDispatcher\Event;
  * information along to the selected variant:
  * - self::setPluginConfiguration()
  * - self::setContexts()
+ * - self::addCacheableDependency()
  *
  * @see \Drupal\Core\Render\RenderEvents::SELECT_PAGE_DISPLAY_VARIANT
  * @see \Drupal\Core\Render\MainContent\HtmlRenderer
  */
-class PageDisplayVariantSelectionEvent extends Event {
+class PageDisplayVariantSelectionEvent extends Event implements RefinableCacheableDependencyInterface {
+
+  use RefinableCacheableDependencyTrait;
 
   /**
    * The selected page display variant plugin ID.

core/modules/system/src/Tests/Render/DisplayVariantTest.php

@@ -33,6 +33,7 @@ class DisplayVariantTest extends WebTestBase {
     $this->drupalGet('<front>');
     $this->assertRaw('A very important, required value.');
     $this->assertRaw('Explicitly passed in context.');
+    $this->assertCacheTag('custom_cache_tag');
   }
 
 }

core/modules/system/tests/modules/display_variant_test/src/EventSubscriber/TestPageDisplayVariantSubscriber.php

@@ -27,6 +27,7 @@ class TestPageDisplayVariantSubscriber implements EventSubscriberInterface {
   public function onSelectPageDisplayVariant(PageDisplayVariantSelectionEvent $event) {
     $event->setPluginId('display_variant_test');
     $event->setPluginConfiguration(['required_configuration' => 'A very important, required value.']);
+    $event->addCacheTags(['custom_cache_tag']);
 
     $context = new Context(new ContextDefinition('string', NULL, TRUE));
     $context->setContextValue('Explicitly passed in context.');

core/modules/system/tests/modules/display_variant_test/src/Plugin/DisplayVariant/TestDisplayVariant.php

@@ -7,6 +7,7 @@
 
 namespace Drupal\display_variant_test\Plugin\DisplayVariant;
 
+use Drupal\Core\Cache\CacheableMetadata;
 use Drupal\Core\Display\VariantBase;
 use Drupal\Core\Display\PageVariantInterface;
 use Drupal\Core\Display\ContextAwareVariantInterface;
@@ -86,6 +87,9 @@ class TestDisplayVariant extends VariantBase implements PageVariantInterface, Co
     $build['content']['default'] = [
       '#markup' => $config['required_configuration'] . ' ' . $contexts['context']->getContextValue(),
     ];
+
+    CacheableMetadata::createFromObject($this)->applyTo($build);
+
     return $build;
   }