minor defensive coding improvements

Author: dannyvankooten

src/admin/class-admin.php

@@ -734,6 +734,9 @@ public function flush_rules($post_id)
             foreach ($boxes as $box) {
                 // get box meta data
                 $box_meta = get_post_meta($box->ID, 'boxzilla_options', true);
+                if (! $box_meta || ! is_array($box_meta) || empty($box_meta['rules'])) {
+                    continue;
+                }
 
                 // add box rules to all rules
                 $rules[ $box->ID ]                = (array) $box_meta['rules'];

src/admin/class-menu.php

@@ -2,13 +2,9 @@
 
 namespace Boxzilla\Admin;
 
-use Boxzilla\Plugin;
-use Boxzilla\Box;
-use Boxzilla\Boxzilla;
-
 class Menu
 {
-    public function init()
+    public function init(): void
     {
         add_action('admin_head-nav-menus.php', [ $this, 'add_nav_menu_meta_boxes' ]);
 
@@ -48,6 +44,9 @@ private function get_boxes()
     public function nav_menu_links()
     {
         $posts = $this->get_boxes();
+        if (count($posts) === 0) {
+            return;
+        }
 
         ?>
         <div id="posttype-boxzilla-boxes" class="posttypediv">

src/class-box.php

@@ -41,10 +41,13 @@ class Box
      */
     public function __construct($post)
     {
-
         // fetch post if it hasn't been fetched yet
         if (! $post instanceof WP_Post) {
             $post = get_post($post);
+
+            if ($post === null) {
+                throw new \InvalidArgumentException('No post found with ID ' . $post);
+            }
         }
 
         // store ref to post