[4.0] Get categories from component

administrator/components/com_fields/src/Model/FieldsModel.php

@@ -11,7 +11,8 @@
 
 \defined('_JEXEC') or die;
 
-use Joomla\CMS\Categories\Categories;
+use Joomla\CMS\Categories\CategoryServiceInterface;
+use Joomla\CMS\Categories\SectionNotFoundException;
 use Joomla\CMS\Factory;
 use Joomla\CMS\MVC\Factory\MVCFactoryInterface;
 use Joomla\CMS\MVC\Model\ListModel;
@@ -199,14 +200,43 @@ protected function getListQuery()
 
 			if ($parts)
 			{
-				// Get the category
-				$cat = Categories::getInstance(str_replace('com_', '', $parts[0]) . '.' . $parts[1]);
+				// Get the categories for this component (and optionally this section, if available)
+				$cat = (
+					function () use ($parts) {
+						// Get the CategoryService for this component
+						$componentObject = $this->bootComponent($parts[0]);
 
-				// If there is no category for the component and section, so check the component only
-				if (!$cat)
-				{
-					$cat = Categories::getInstance(str_replace('com_', '', $parts[0]));
-				}
+						if (!$componentObject instanceof CategoryServiceInterface)
+						{
+							// No CategoryService -> no categories
+							return null;
+						}
+
+						$cat = null;
+
+						// Try to get the categories for this component and section
+						try
+						{
+							$cat = $componentObject->getCategory([], $parts[1] ?: '');
+						}
+						catch (SectionNotFoundException $e)
+						{
+							// Not found for component and section -> Now try once more without the section, so only component
+							try
+							{
+								$cat = $componentObject->getCategory();
+							}
+							catch (SectionNotFoundException $e)
+							{
+								// If we haven't found it now, return (no categories available for this component)
+								return null;
+							}
+						}
+
+						// So we found categories for at least the component, return them
+						return $cat;
+					}
+				)();
 
 				if ($cat)
 				{