JezK

Edit File: class-admin-messages.php

<?php

defined('ABSPATH') or exit;

/**
 * Class MC4WP_Admin_Messages
 *
 * @ignore
 * @since 3.0
 */
class MC4WP_Admin_Messages
{
    /**
     * @var array
     */
    protected $bag;

/**
     * @var bool
     */
    protected $dirty = false;

/**
     * Add hooks
     */
    public function add_hooks()
    {
        add_action('admin_notices', [ $this, 'show' ]);
        register_shutdown_function([ $this, 'save' ]);
    }

private function load()
    {
        if (is_null($this->bag)) {
            $this->bag = get_option('mc4wp_flash_messages', []);
        }
    }

// empty flash bag
    private function reset()
    {
        $this->bag   = [];
        $this->dirty = true;
    }

/**
     * Flash a message (shows on next pageload)
     *
     * @param string $message
     * @param string $type
     */
    public function flash($message, $type = 'success')
    {
        $this->load();
        $this->bag[] = [
            'text' => $message,
            'type' => $type,
        ];
        $this->dirty = true;
    }

/**
     * Show queued flash messages
     */
    public function show()
    {
        $this->load();

$allowed_html = [
            'a' => [ 'href' => [] ],
            'br' => [],
            'strong' => [],
        ];

foreach ($this->bag as $message) {
            printf('<div class="notice notice-%s is-dismissible"><p>%s</p></div>', esc_attr($message['type']), wp_kses($message['text'], $allowed_html));
        }

$this->reset();
    }

/**
     * Save queued messages
     *
     * @hooked `shutdown`
     */
    public function save()
    {
        if ($this->dirty) {
            update_option('mc4wp_flash_messages', $this->bag, false);
        }
    }
}