comparison core/lib/Drupal/Core/Theme/ThemeManager.php @ 18:af1871eacc83

Update to Drupal core 8.7.1

       if (empty($extra_types)) {
         unset($extra_types);
       }
     }
 
-    $theme_keys = [];
-    foreach ($theme->getBaseThemes() as $base) {
-      $theme_keys[] = $base->getName();
-    }
-
+    $theme_keys = array_keys($theme->getBaseThemeExtensions());
     $theme_keys[] = $theme->getName();
     $functions = [];
     foreach ($theme_keys as $theme_key) {
       $function = $theme_key . '_' . $type . '_alter';
       if (function_exists($function)) {