简化代码

application/common/controller/Backend.php

@@ -581,7 +581,7 @@ class Backend extends Controller
                 } else {
                     $result = array_intersect_key(($item instanceof Model ? $item->toArray() : (array)$item), array_flip($fields));
                 }
-                $result['pid'] = isset($item['pid']) ? $item['pid'] : (isset($item['parent_id']) ? $item['parent_id'] : 0);
+                $result['pid'] = (int)($item['pid'] ?? $item['parent_id'] ?? 0);
                 // 修改为安全的htmlentities调用，兼容php8+版本
                 $result = array_map(function($value) {
                     return $value === null ? '' : htmlentities((string)$value);