Ticket #54160: 54160.diff

wp-includes/formatting.php

@@ -2125 +2125 @@
 }
 
 /**
  * Sanitizes a string key.
  *
  * Keys are used as internal identifiers. Lowercase alphanumeric characters,
  * dashes, and underscores are allowed.
  *
  * @since 3.0.0
  *
  * @param string $key String key
  * @return string Sanitized key
  */
 function sanitize_key( $key ) {
         $raw_key = $key;
-        $key     = strtolower( $key );
-        $key     = preg_replace( '/[^a-z0-9_\-]/', '', $key );
+        if ( ! is_string( $key ) ) {
+                $key = '';
+        }
+
+        $key = strtolower( $key );
+        $key = preg_replace( '/[^a-z0-9_\-]/', '', $key );
 
         /**
          * Filters a sanitized key string.
          *
          * @since 3.0.0
          *
          * @param string $key     Sanitized key.
          * @param string $raw_key The key prior to sanitization.
          */
         return apply_filters( 'sanitize_key', $key, $raw_key );
 }
 
 /**
  * Sanitizes a string into a slug, which can be used in URLs or HTML attributes.
  *