[wp-trac] [WordPress Trac] #57271: Cron unschedule / reschedule event errors

[WordPress Trac]

#57271: Cron unschedule / reschedule event errors
--------------------------------------+------------------------------
 Reporter:  domainsupport             |       Owner:  audrasjb
     Type:  defect (bug)              |      Status:  assigned
 Priority:  normal                    |   Milestone:  Awaiting Review
Component:  Cron API                  |     Version:  6.0
 Severity:  normal                    |  Resolution:
 Keywords:  has-patch has-unit-tests  |     Focuses:
--------------------------------------+------------------------------

Comment (by Andy Schmidt):

 Ultimately, one problem is a lack of differentiating the possible outcome
 of database updates:

 - WHERE matched, and value set.
 - WHERE matched, and **value already set.**
 - WHERE did not match.

 In most situations, the third outcome would truly be "unintended" and
 require error handling.

 However, the **second outcome** might be "unexpected", but still perfectly
 ACCEPTABLE for the subsequent program flow (after all the value still DOES
 have the intended value once the UPDATE was issued).

 Ideally, the WPDB class would offer an additional method/property that
 returns the mysqli_info, similar to this:

 {{{
 if ( 1 === preg_match(
 '/^(?:.+\s+)*([\w]+):\s+(\d+)\s+([\w]+):\s+(\d+)\s+([\w]+):\s+(\d+)\s*$/U',
 strtolower( (string) mysqli_info( $this->dbh ) ), $matches,
 PREG_UNMATCHED_AS_NULL ) ) {
         $this->mysql_info = array( $matches[1] => (int) $matches[2],
 $matches[3] => (int) $matches[4], $matches[5] => (int) $matches[6] );
 }
 }}}

 This way, callers could opt to confirm
 {{{
 $wpdb->mysql_info['matched'] > 1
 }}}
 whenever mysqli_affected_rows === 0, and treat this as an acceptable
 outcome.

 I realize that it's unlikely that WPDB be improved - so for now, I'm
 trying this patch to cron.php:


 {{{
 function _set_cron_array( $cron, $wp_error = false ) {
         if ( ! is_array( $cron ) ) {
                 $cron = array();
         }

         $cron['version'] = 2;

         $result = update_option( 'cron', $cron );

         /* PATCH: Allow option_value to already contain intended value
 *************  */
         if ( 0 === $result ) {
                 // Qualify why 0 rows were affected.
                 global $wpdb;
                 if ( 1 === sscanf( (string) mysqli_info( $wpdb->dbh ),
 'Rows matched: %d', $mysql_matched ) and $mysql_matched > 0 )
                         // Rows did match; fields just had intended
 content already.
                         return $result;
         }
         /* PATCH END
 **************************************************************** */

         if ( $wp_error && ! $result ) {
                 return new WP_Error(
                         'could_not_set',
                         __( 'The cron event list could not be saved.' )
                 );
         }

         return $result;
 }

 }}}

-- 
Ticket URL: <https://core.trac.wordpress.org/ticket/57271#comment:93>
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