PHP, WP/CP | Type: PHPPatch count(): countable in wp-includes/post-template.php on line 284

Normally a bad idea to patch a WP core file, but here’s the patch:

// original code:
if ( $page > count( $pages ) )
//add BEFORE above code:
if (empty($pages)) $pages = [];

Reference Links

https://generatepress.com/forums/topic/php-warning-count-countable-in-wp-includes-post-template-php-on-line-284/