Issue #2460911 by Wim Leers, jhodgdon: Search reindexing should invalidate cache tags

core/modules/node/src/Plugin/Search/NodeSearch.php

@@ -174,6 +174,13 @@ public function isSearchExecutable() {
     return !empty($this->keywords) || (isset($this->searchParameters['f']) && count($this->searchParameters['f']));
   }
 
+  /**
+   * {@inheritdoc}
+   */
+  public function getType() {
+    return $this->getPluginId();
+  }
+
   /**
    * {@inheritdoc}
    */

core/modules/search/search.module

@@ -8,6 +8,7 @@
 use Drupal\Component\Utility\SafeMarkup;
 use Drupal\Component\Utility\Html;
 use Drupal\Component\Utility\Unicode;
+use Drupal\Core\Cache\Cache;
 use Drupal\Core\Form\FormStateInterface;
 use Drupal\Core\Routing\RouteMatchInterface;
 
@@ -152,6 +153,15 @@ function search_index_clear($type = NULL, $sid = NULL, $langcode = NULL) {
 
   $query_index->execute();
   $query_dataset->execute();
+
+  if ($type) {
+    // Invalidate all render cache items that contain data from this index.
+    Cache::invalidateTags(['search_index:' . $type]);
+  }
+  else {
+    // Invalidate all render cache items that contain data from any index.
+    Cache::invalidateTags(['search_index']);
+  }
 }
 
 /**
@@ -499,6 +509,8 @@ function search_index($type, $sid, $langcode, $text) {
     $tag = !$tag;
   }
 
+  // Remove the item $sid from the search index, and invalidate the relevant
+  // cache tags.
   search_index_clear($type, $sid, $langcode);
 
   // Insert cleaned up data into dataset

core/modules/search/src/Controller/SearchController.php

@@ -7,6 +7,7 @@
 
 namespace Drupal\search\Controller;
 
+use Drupal\Core\Cache\Cache;
 use Drupal\Core\Config\ConfigFactory;
 use Drupal\Core\Controller\ControllerBase;
 use Drupal\search\SearchPageInterface;
@@ -127,6 +128,14 @@ public function view(Request $request, SearchPageInterface $entity) {
       ),
     );
 
+    // If this plugin uses a search index, then also add the cache tag tracking
+    // that search index, so that cached search result pages are invalidated
+    // when necessary.
+    if ($plugin->getType()) {
+      $build['search_results']['#cache']['tags'][] = 'search_index';
+      $build['search_results']['#cache']['tags'][] = 'search_index:' . $plugin->getType();
+    }
+
     $build['pager'] = array(
       '#type' => 'pager',
     );

core/modules/search/src/Plugin/SearchInterface.php

@@ -64,6 +64,18 @@ public function getAttributes();
    */
   public function isSearchExecutable();
 
+  /**
+   * Returns the search index type this plugin uses.
+   *
+   * @return string|null
+   *   The type used by this search plugin in the search index, or NULL if this
+   *   plugin does not use the search index.
+   *
+   * @see search_index()
+   * @see search_index_clear()
+   */
+  public function getType();
+
   /**
    * Executes the search.
    *

core/modules/search/src/Plugin/SearchPluginBase.php

@@ -85,6 +85,13 @@ public function isSearchExecutable() {
     return !empty($this->keywords);
   }
 
+  /**
+   * {@inheritdoc}
+   */
+  public function getType() {
+    return NULL;
+  }
+
   /**
    * {@inheritdoc}
    */

core/modules/search/src/Tests/SearchPageCacheTagsTest.php

@@ -13,6 +13,7 @@
  * @group search
  */
 class SearchPageCacheTagsTest extends SearchTestBase {
+
   /**
    * {@inheritdoc}
    */
@@ -25,11 +26,33 @@ class SearchPageCacheTagsTest extends SearchTestBase {
    */
   protected $searchingUser;
 
+  /**
+   * A node that is indexed by the search module.
+   *
+   * @var \Drupal\node\NodeInterface
+   */
+  protected $node;
+
+  /**
+   * {@inheritdoc}
+   */
   protected function setUp() {
     parent::setUp();
 
+    // Enable the page cache.
+    // @todo Remove in https://www.drupal.org/node/606840.
+    $config = $this->config('system.performance');
+    $config->set('cache.page.use_internal', 1);
+    $config->set('cache.page.max_age', 300);
+    $config->save();
+
     // Create user.
     $this->searchingUser = $this->drupalCreateUser(array('search content', 'access user profiles'));
+
+    // Create a node and update the search index.
+    $this->node = $this->drupalCreateNode(['title' => 'bike shed shop']);
+    $this->container->get('plugin.manager.search')->createInstance('node_search')->updateIndex();
+    search_update_totals();
   }
 
   /**
@@ -40,26 +63,47 @@ function testSearchText() {
 
     // Initial page for searching nodes.
     $this->drupalGet('search/node');
-    $cache_tags = explode(' ', $this->drupalGetHeader('X-Drupal-Cache-Tags'));
-    $this->assertTrue(in_array('config:search.page.node_search', $cache_tags));
+    $this->assertCacheTag('config:search.page.node_search');
+    $this->assertCacheTag('search_index:node_search');
 
     // Node search results.
     $edit = array();
     $edit['keys'] = 'bike shed';
     $this->drupalPostForm('search/node', $edit, t('Search'));
-    $cache_tags = explode(' ', $this->drupalGetHeader('X-Drupal-Cache-Tags'));
-    $this->assertTrue(in_array('config:search.page.node_search', $cache_tags));
+    $this->assertText('bike shed shop');
+    $this->assertCacheTag('config:search.page.node_search');
+    $this->assertCacheTag('search_index');
+    $this->assertCacheTag('search_index:node_search');
+
+    // Updating a node should invalidate the search plugin's index cache tag.
+    $this->node->title = 'bike shop';
+    $this->node->save();
+    $this->drupalPostForm('search/node', $edit, t('Search'));
+    $this->assertText('bike shop');
+    $this->assertCacheTag('config:search.page.node_search');
+    $this->assertCacheTag('search_index');
+    $this->assertCacheTag('search_index:node_search');
+
+    // Deleting a node should invalidate the search plugin's index cache tag.
+    $this->node->delete();
+    $this->drupalPostForm('search/node', $edit, t('Search'));
+    $this->assertText('Your search yielded no results.');
+    $this->assertCacheTag('config:search.page.node_search');
+    $this->assertCacheTag('search_index');
+    $this->assertCacheTag('search_index:node_search');
 
     // Initial page for searching users.
     $this->drupalGet('search/user');
-    $cache_tags = explode(' ', $this->drupalGetHeader('X-Drupal-Cache-Tags'));
-    $this->assertTrue(in_array('config:search.page.user_search', $cache_tags));
+    $this->assertCacheTag('config:search.page.user_search');
+    $this->assertNoCacheTag('search_index');
+    $this->assertNoCacheTag('search_index:user_search');
 
     // User search results.
     $edit['keys'] = $this->searchingUser->getUsername();
     $this->drupalPostForm('search/user', $edit, t('Search'));
-    $cache_tags = explode(' ', $this->drupalGetHeader('X-Drupal-Cache-Tags'));
-    $this->assertTrue(in_array('config:search.page.user_search', $cache_tags));
+    $this->assertCacheTag('config:search.page.user_search');
+    $this->assertNoCacheTag('search_index');
+    $this->assertNoCacheTag('search_index:user_search');
   }
 
 }

core/modules/simpletest/src/WebTestBase.php

@@ -2762,4 +2762,15 @@ protected function assertCacheTag($expected_cache_tag) {
     $this->assertTrue(in_array($expected_cache_tag, $cache_tags), "'" . $expected_cache_tag . "' is present in the X-Drupal-Cache-Tags header.");
   }
 
+  /**
+   * Asserts whether an expected cache tag was absent in the last response.
+   *
+   * @param string $cache_tag
+   *   The cache tag to check.
+   */
+  protected function assertNoCacheTag($cache_tag) {
+    $cache_tags = explode(' ', $this->drupalGetHeader('X-Drupal-Cache-Tags'));
+    $this->assertFalse(in_array($cache_tag, $cache_tags), "'" . $cache_tag . "' is absent in the X-Drupal-Cache-Tags header.");
+  }
+
 }