Fix Warning: in_array() expects parameter 2 to be array, null given

I have tried to enable the script tag in the posts/pages by using the following approach in one of my Wordpress blog (version 4.9)

steps to reproduce:

1. add define define('CUSTOM_TAGS', true); in wp_config.php
2. add the following to functions.php template

function add_scriptfilter( $string ) {
  global $allowedtags;
  $allowedtags['script'] = array( 'src' => array () );
  return $string;
}
add_filter( 'pre_kses', 'add_scriptfilter' );

and it will show this warnings to all pages/posts:

Warning: in_array() expects parameter 2 to be array, null given in wp-includes/kses.php on line 1416

The error is quite straightforward, and therefore I fix it and create a PR, which I hope that can be merged into next release!

The PR is at:
https://github.com/WordPress/WordPress/pull/321

---

Posted on Utopian.io - Rewarding Open Source Contributors

---