Fatal Error – Upgrading 4.5.1

Hi Pierre

I was running on 4.5.0 perfectly and got a Fatal Error when upgrading to 4.5.1

Not even recovery mode was able to handle it as I was getting “ERR_TOO_MANY_REDIRECTS” errors on any page and had to disable plugin via FTP to get back online.

Not sure if there are any relation but I’m running on Cloudflare and use Super Page Cache that’s more suitable for Cloudflare in my case as well as WP Asset Clean UP

Checking error logs, I can see multiple similar errors below:

PHP Fatal error:  Uncaught TypeError: Cannot access offset of type string on string in /home/user/domain.com/wp-content/plugins/apcu-manager/includes/api/object-class.php:642
Stack trace:
#0 /home/user/domain.com/wp-content/plugins/apcu-manager/includes/api/object-class.php(590): WP_Object_Cache->partial_flush_persistent(Array)
#1 /home/user/domain.com/wp-content/object-cache.php(310): WP_Object_Cache->flush_group('options')
#2 /home/user/domain.com/wp-content/plugins/ws-action-scheduler-cleaner/includes/class-scheduler.php(239): wp_cache_flush_group('options')
#3 /home/user/domain.com/wp-content/plugins/ws-action-scheduler-cleaner/includes/class-scheduler.php(443): WSACSC_Scheduler::invalidate_cron_cache()
#4 /home/user/domain.com/wp-content/plugins/ws-action-scheduler-cleaner/includes/class-scheduler.php(671): WSACSC_Scheduler::schedule_with_retry(1784806927, 'wsacsc_every_10...', 'wsacsc_cleanup_...')
#5 /home/user/domain.com/wp-includes/class-wp-hook.php(341): WSACSC_Scheduler::maybe_schedule_cleanup('')
#6 /home/user/domain.com/wp-includes/class-wp-hook.php(365): WP_Hook->apply_filters(Object(WPMailSMTP\ConnectionsManager), Array)
#7 /home/user/domain.com/wp-includes/plugin.php(522): WP_Hook->do_action(Array)
#8 /home/user/domain.com/wp-settings.php(622): do_action('plugins_loaded')
#9 /home/user/domain.com/wp-config.php(90): require_once('/home/user...')
#10 /home/user/domain.com/wp-load.php(50): require_once('/home/user...')
#11 /home/user/domain.com/wp-admin/admin-ajax.php(22): require_once('/home/cpcinst10...')
#12 {main}
  thrown in /home/user/domain.com/wp-content/plugins/apcu-manager/includes/api/object-class.php on line 642