Title: PHP Fatal error : callback is_numeric
Last modified: June 11, 2022

---

# PHP Fatal error : callback is_numeric

 *  [JP3](https://wordpress.org/support/users/jp3/)
 * (@jp3)
 * [3 years, 11 months ago](https://wordpress.org/support/topic/php-fatal-error-callback-is_numeric/)
 * Took me a while to find the source of these messages, but I finally did.
 * Message showing up in my debug log on every “save_post” call, regardless of whether
   I used your plugin to set a custom permalink for that post_id or not:
 * > `PHP Fatal error: Uncaught ArgumentCountError: is_numeric() expects exactly
   > 1 argument, 3 given in /path/to/wp-includes/rest-api/class-wp-rest-request.
   > php:910
   >  Stack trace: #0 /path/to/wp-includes/rest-api/class-wp-rest-request.
   > php(910): is_numeric(‘118’, Object(WP_REST_Request), ‘id’) #1 /path/to/wp-includes/
   > rest-api/class-wp-rest-server.php(979): WP_REST_Request->has_valid_params()#
   > 2 /path/to/wp-includes/rest-api/class-wp-rest-server.php(414): WP_REST_Server-
   > >dispatch(Object(WP_REST_Request)) #3 /path/to/wp-includes/rest-api.php(394):
   > WP_REST_Server->serve_request(‘/custom-permali…’) #4 /path/to/wp-includes/class-
   > wp-hook.php(307): rest_api_loaded(Object(WP)) #5 /path/to/wp-includes/class-
   > wp-hook.php(331): WP_Hook->apply_filters(”, Array) #6 /path/to/wp-includes/
   > plugin.php(524): WP_Hook->do_action(Array) #7 /path/to/wp-includes/class-wp.
   > php(398): do_action_ref_array(‘parse_request’, Array) #8 /path/to/wp-includes/
   > class-wp.php(770): WP->parse_request(”) #9 /path/to/wp-includes/functions.php(
   > 1330): WP->main(”) #10 /path/to/wp-blog-header.php(16): wp() #11 /path/to/index.
   > php(17): require(‘/path/to/wp-blog-header.php’) #12 {main} thrown in /path/
   > to/wp-includes/rest-api/class-wp-rest-request.php on line 910`
 * Here’s the WP Core topic on it:
    [https://core.trac.wordpress.org/ticket/54043](https://core.trac.wordpress.org/ticket/54043)
 * Apparently prior to PHP 8, it just kicked out a warning, but as of PHP 8 it’s
   a fatal error.
 * WP suggestion as per the link above: contact you and let you know.
 * The problem is in /path/to/wp-content/plugins/custom-permalink-editor/includes/
   class-custom-permalink-editor-form.php
 * Specifically the method “rest_edit_form” on line 857 (plugin version 1.0.3), 
   and even more specifically the line (line # 866) that says:
    `'validate_callback'
   => 'is_numeric',`
 * Any “save_post” action that uses more than 1 parameter kicks out this error. 
   For example:
 *     ```
       function intercept_post_save( $post_id, $post, $update ) {
       	// code to process input before saving post data to DB	
       }
       add_action( 'save_post', 'intercept_post_save', 5, 3 );
       ```
   
 * I wish I had a solution to offer you. One suggestion is to only call the “rest_edit_form”
   method or only “register_rest_route” if/when there’s actually a custom permalink
   set. Would get rid of the majority of errors, but not all of them. Not sure about
   how this issue/solution affects rest routes (broken?).
 * Wish I had more to offer, but this should help resolve it.

The topic ‘PHP Fatal error : callback is_numeric’ is closed to new replies.

 * ![](https://ps.w.org/custom-permalink-editor/assets/icon-256x256.png?rev=2624415)
 * [Custom Permalink Editor](https://wordpress.org/plugins/custom-permalink-editor/)
 * [Frequently Asked Questions](https://wordpress.org/plugins/custom-permalink-editor/#faq)
 * [Support Threads](https://wordpress.org/support/plugin/custom-permalink-editor/)
 * [Active Topics](https://wordpress.org/support/plugin/custom-permalink-editor/active/)
 * [Unresolved Topics](https://wordpress.org/support/plugin/custom-permalink-editor/unresolved/)
 * [Reviews](https://wordpress.org/support/plugin/custom-permalink-editor/reviews/)

## Tags

 * [fatal error](https://wordpress.org/support/topic-tag/fatal-error/)
 * [rest](https://wordpress.org/support/topic-tag/rest/)
 * [Uncaught ArgumentCountError](https://wordpress.org/support/topic-tag/uncaught-argumentcounterror/)

 * 0 replies
 * 1 participant
 * Last reply from: [JP3](https://wordpress.org/support/users/jp3/)
 * Last activity: [3 years, 11 months ago](https://wordpress.org/support/topic/php-fatal-error-callback-is_numeric/)
 * Status: not resolved