[SD-1497] Added cachebale dependencies for publication navigation computed fields.

modules/tide_publication/src/Navigation/Children.php

@@ -5,7 +5,7 @@
 use Drupal\Core\Cache\CacheableMetadata;
 
 /**
- * Class Root.
+ * Class Children for navigation.
  */
 class Children extends Base {
 
@@ -44,6 +44,10 @@ protected function computeValue() {
 
       $this->list[] = $this->createItem($weight, ['target_id' => $child_id]);
     }
+
+    // Add the collected cacheable metadata to the parent entity.
+    // If any child changes, the cache for this field is invalidated.
+    $entity->addCacheableDependency($cache);
   }
 
 }

modules/tide_publication/src/Navigation/Next.php

@@ -31,11 +31,16 @@ protected function computeValue() {
           $next = $delta + 1;
           if (isset($hierarchy[$next])) {
             $this->list[] = $this->createItem(0, ['target_id' => $hierarchy[$next]['entity_id']]);
-            return;
+            // Break the loop and proceed to add cache metadata.
+            break;
           }
         }
       }
     }
+
+    // Add the collected cacheable metadata to the parent entity.
+    // Make sure field invalidates if the root or any hierarchy node changes.
+    $entity->addCacheableDependency($cache);
   }
 
 }

modules/tide_publication/src/Navigation/Previous.php

@@ -5,7 +5,7 @@
 use Drupal\Core\Cache\CacheableMetadata;
 
 /**
- * Class Next.
+ * Class Previous for navigation.
  */
 class Previous extends Base {
 
@@ -31,11 +31,16 @@ protected function computeValue() {
           $prev = $delta - 1;
           if (isset($hierarchy[$prev])) {
             $this->list[] = $this->createItem(0, ['target_id' => $hierarchy[$prev]['entity_id']]);
-            return;
+            // Use break instead of return so we reach the cache dependency call below.
+            break;
           }
         }
       }
     }
+
+    // Attach the collected cache metadata to the entity.
+    // Tells Drupal field depends on all nodes in the hierarchy.
+    $entity->addCacheableDependency($cache);
   }
 
 }