我正在使用以下函数（不记得在哪里找到它，但我认为它是由pippin编写的，多亏了他）来测试一个短代码。

function has_shortcode($shortcode = \'\') {

   $post_to_check = get_post( get_the_ID() );

   // false because we have to search through the post content first
   $found = false;

   // if no short code was provided, return false
   if ( !$shortcode ) {
      return $found;
   }

   if (  stripos( $post_to_check->post_content, \'[\' . $shortcode ) !== false ) {
      // we have found the short code
      $found = true;
   }

   // return our final results
   return $found;
}

问题是，在404页这样的页面上，我会遇到以下错误：

Notice: Trying to get property of non-object in /wp-includes/post-template.php on line 30
Notice: Trying to get property of non-object in theme-functions.php on line 49

第49行中的主题函数是上述函数的这一行

if (  stripos( $post_to_check->post_content, \'[\' . $shortcode ) !== false ) {

如果我删除函数调用if( has_shortcode(\'gallery\') ) ... 从另一个文件中，这两个错误消失了。我相信这两者是相关的，如果我修复了该功能，它将同时清除它们。我可以“有点”理解为什么会这样。。。我的理解是，在404页面上没有$post变量集，因此我需要修改函数以首先进行测试。我说得对吗？

function has_shortcode($shortcode = \'\') {
  global $post;
 // false because we have to search through the post content first
 $found = false;

 // if no short code was provided, return false
 if ( !$shortcode ) {
    return $found;
 }

 if (  is_object( $post ) && stripos( $post->post_content, \'[\' . $shortcode ) !== false ) {
     // we have found the short code
  $found = true;
 }

// return our final results
return $found;
}