Do not invalidate group content list cache tags when the group itself…

… changes (#509)

Do not invalidate group content list cache tags when the group itself changes

og.module

@@ -329,12 +329,10 @@ function og_theme($existing, $type, $theme, $path) {
 function og_invalidate_group_content_cache_tags(EntityInterface $entity) {
   // If group content is created or updated, invalidate the group content cache
   // tags for each of the groups this group content belongs to. This allows
-  // group listings to be cached effectively. Also invalidate the tags if the
-  // group itself changes. The cache tag format is
+  // group listings to be cached effectively. The cache tag format is
   // 'og-group-content:{group entity type}:{group entity id}'.
   $is_group_content = Og::isGroupContent($entity->getEntityTypeId(), $entity->bundle());
-  $group_is_updated = Og::isGroup($entity->getEntityTypeId(), $entity->bundle()) && !empty($entity->original);
-  if ($group_is_updated || $is_group_content) {
+  if ($is_group_content) {
     /** @var \Drupal\og\MembershipManagerInterface $membership_manager */
     $membership_manager = \Drupal::service('og.membership_manager');
     $tags = [];
@@ -345,7 +343,7 @@ function og_invalidate_group_content_cache_tags(EntityInterface $entity) {
     // the tags of the old group(s).
     /** @var \Drupal\Core\Entity\FieldableEntityInterface $entity */
     $original = !empty($entity->original) ? $entity->original : NULL;
-    if ($is_group_content && $original) {
+    if ($original) {
       /** @var \Drupal\og\OgGroupAudienceHelperInterface $group_audience_helper */
       $group_audience_helper = \Drupal::service('og.group_audience_helper');
       /** @var \Drupal\Core\Entity\FieldableEntityInterface $original */

tests/src/Kernel/Entity/CacheInvalidationOnGroupChangeTest.php

@@ -1,20 +1,30 @@
 <?php
 
+declare(strict_types = 1);
+
 namespace Drupal\Tests\og\Kernel\Entity;
 
 use Drupal\Core\Cache\Cache;
+use Drupal\Core\Entity\ContentEntityInterface;
 use Drupal\entity_test\Entity\EntityTest;
 use Drupal\KernelTests\KernelTestBase;
 use Drupal\og\Og;
 use Drupal\og\OgGroupAudienceHelperInterface;
 
 /**
- * Tests if the cache is correctly invalidated on group change.
+ * Tests if group content listings are invalidated when group audience changes.
  *
  * @group og
  */
 class CacheInvalidationOnGroupChangeTest extends KernelTestBase {
 
+  /**
+   * The cache backend.
+   *
+   * @var \Drupal\Core\Cache\CacheBackendInterface
+   */
+  protected $cache;
+
   /**
    * {@inheritdoc}
    */
@@ -35,6 +45,8 @@ protected function setUp() {
     $this->installEntitySchema('entity_test');
     $this->installEntitySchema('user');
 
+    $this->cache = $this->container->get('cache.default');
+
     // Add a OG group audience.
     Og::groupTypeManager()->addGroup('entity_test', 'group');
     $settings = [
@@ -61,39 +73,126 @@ protected function setUp() {
    */
   public function testCacheInvalidationOnGroupChange() {
     // Create two groups.
-    $group1 = EntityTest::create([
-      'type' => 'group',
-      'name' => $this->randomString(),
-    ]);
-    $group1->save();
-    $group2 = EntityTest::create([
-      'type' => 'group',
-      'name' => $this->randomString(),
-    ]);
-    $group2->save();
+    $groups = [];
+    for ($i = 0; $i < 2; $i++) {
+      $groups[$i] = EntityTest::create([
+        'type' => 'group',
+        'name' => $this->randomString(),
+      ]);
+      $groups[$i]->save();
+    }
 
-    // Create a group content.
+    // Create a group content entity that belong to the first group.
     $group_content = EntityTest::create([
       'type' => 'group_content',
       'name' => $this->randomString(),
-      OgGroupAudienceHelperInterface::DEFAULT_FIELD => $group1->id(),
+      OgGroupAudienceHelperInterface::DEFAULT_FIELD => $groups[0]->id(),
     ]);
     $group_content->save();
 
-    // Cache some arbitrary data tagged with the OG group content tag.
-    $bin = \Drupal::cache();
-    $cid = strtolower($this->randomMachineName());
-    $tags = Cache::buildTags('og-group-content', $group1->getCacheTagsToInvalidate());
-    $bin->set($cid, $this->randomString(), Cache::PERMANENT, $tags);
+    // Cache some arbitrary data tagged with the OG group content tags for both
+    // groups.
+    $this->populateCache($groups[0]);
+    $this->populateCache($groups[1]);
 
+    // Sanity check, the cached content listings of both groups should be
+    // populated.
+    $this->assertCachePopulated($groups[0]);
+    $this->assertCachePopulated($groups[1]);
+
+    // Change the label of group 1. This should not affect any of the cached
+    // listings.
+    $groups[0]->setName($this->randomString())->save();
+    $this->assertCachePopulated($groups[0]);
+    $this->assertCachePopulated($groups[1]);
+
+    // Move the group content from group 1 to group 2. This should invalidate
+    // the group content list cache tags of both groups.
     $group_content
-      ->set(OgGroupAudienceHelperInterface::DEFAULT_FIELD, $group2->id())
+      ->set(OgGroupAudienceHelperInterface::DEFAULT_FIELD, $groups[1]->id())
       ->save();
 
     // Cache entries tagged with 'og-group-content:entity_type:{$group->id()}'
     // should have been invalidated at this point because the content members of
-    // $group1 have changed.
-    $this->assertFalse($bin->get($cid));
+    // both groups have changed.
+    $this->assertCacheNotPopulated($groups[0]);
+    $this->assertCacheNotPopulated($groups[1]);
+
+    // Now populate both caches while including the cache tags of the group
+    // itself. This can happen for example if a listing of group content is
+    // shown that includes the group name in its content.
+    $this->populateCache($groups[0], TRUE);
+    $this->populateCache($groups[1], TRUE);
+
+    // Change the label of group 1. This should invalidate the cache of the
+    // group content listing for group 1, but not for group 2.
+    $groups[0]->setName($this->randomString())->save();
+    $this->assertCacheNotPopulated($groups[0]);
+    $this->assertCachePopulated($groups[1]);
+  }
+
+  /**
+   * Caches a listing of group content that belongs to the given group.
+   *
+   * @param \Drupal\Core\Entity\ContentEntityInterface $group
+   *   The group for which to cache a group content listing.
+   * @param bool $include_group_cache_tag
+   *   Whether or not the group content listing is tagged with the group's cache
+   *   tags.
+   */
+  protected function populateCache(ContentEntityInterface $group, bool $include_group_cache_tag = FALSE): void {
+    $cid = $this->generateCid($group);
+    $tags = Cache::buildTags('og-group-content', $group->getCacheTagsToInvalidate());
+    if ($include_group_cache_tag) {
+      $tags = Cache::mergeTags($tags, $group->getCacheTagsToInvalidate());
+    }
+    $this->cache->set($cid, $this->randomString(), Cache::PERMANENT, $tags);
+  }
+
+  /**
+   * Generates a cache ID for a group content listing of the given group.
+   *
+   * @param \Drupal\Core\Entity\ContentEntityInterface $group
+   *   The group for which to generate a group content listing cache ID.
+   *
+   * @return string
+   *   The cache ID.
+   */
+  protected function generateCid(ContentEntityInterface $group): string {
+    return implode(':', ['my_group_content_listing', $group->id()]);
+  }
+
+  /**
+   * Checks if the group content listing cache for a given group is populated.
+   *
+   * @param \Drupal\Core\Entity\ContentEntityInterface $group
+   *   The group for which to perform the check.
+   */
+  protected function assertCachePopulated(ContentEntityInterface $group): void {
+    $this->assertTrue($this->getCachedData($group));
+  }
+
+  /**
+   * Checks if the group content listing cache for a given group is unpopulated.
+   *
+   * @param \Drupal\Core\Entity\ContentEntityInterface $group
+   *   The group for which to perform the check.
+   */
+  protected function assertCacheNotPopulated(ContentEntityInterface $group): void {
+    $this->assertFalse($this->getCachedData($group));
+  }
+
+  /**
+   * Returns the cached group content listing for a given group, if available.
+   *
+   * @param \Drupal\Core\Entity\ContentEntityInterface $group
+   *   The group for which to return the cached group content listing.
+   *
+   * @return false|object
+   *   The cache item or FALSE on failure.
+   */
+  protected function getCachedData(ContentEntityInterface $group) {
+    return $this->cache->get($this->generateCid($group));
   }
 
 }