Use of Undefined Constant X SLUG Warning

[WPDave]

I recently started receiving this warning message when editing in Cornerstone on one of my sites. At the moment it doesn’t seem to be a problem but it says that in the future it will throw an error.

What is causing this?

[jade]

Hello Dave,

Please check if you have the latest version of X and Cornerstone and that your site meets the general requirements to run X and Cornerstone smoothly:

Version Compatibility | Themeco Docs

Hope this helps.

[WPDave]

I checked all my versions and they’re all up to date and meet the stated requirements for use with Cornerstone. This is a site which had been running Cornerstone with no problems for over a year. It’s a SiteGround server where I also host a dozen other Pro/X/Cornerstone sites with no errors.

Cornerstone V4.2.3
WordPress 5.4.1
PHP Version 7.3.16
Themes, plugins all up to date

DB Server
Server: Localhost via UNIX socket
Server type: Percona Server
Server version: 5.6.40-84.0-log - Percona Server (GPL), Release 84.0, Revision 47234b3
Protocol version: 10

But I continue to get this warning:

Warning: Use of undefined constant X_SLUG - assumed ‘X_SLUG’ (this will throw an Error in a future version of PHP) in /home/videope1/public_html/lagunawoodsdemocrats.org/wp-content/plugins/cornerstone/includes/classes/app/class-app-preferences.php on line 96
…

Any further thoughts?
David Salahi

[friech]

Hi David,

Thank you for writing in, please do the common troubleshooting guide provided here.

Let us know how it goes,
Cheers!

[WPDave]

I disabled all plugins except for the Classic Editor and Cornerstone but the problem persists.

I hesitate to switch themes as I wonder what will happen after I switch to a different theme and then switch back. Will I lose all my Cornerstone settings? Will existing posts come right back formatted & laid out as they are now?

[christian]

Hey David,

I have replicated the warning in my test site so I’ll post this in our issue tracker so it issue will be queued for fixing.

For now, please add the following code in your wp-config.php below the WP_DEBUG line. By the way, set WP_DEBUG to true. What the code will do is enable debugging but not display warnings and errors.

  // Enable Debug logging to the /wp-content/debug.log file
  define( 'WP_DEBUG_LOG', true );

  // Disable display of errors and warnings 
  define( 'WP_DEBUG_DISPLAY', true );
  @ini_set( 'display_errors', 0 );

Please stay tuned for product updates.

Thanks.

[WPDave]

Thank you!

[nabeel]

You’re most welcome David.

Cheers!