fix Got error 'PHP message: PHP Fatal error: Unparenthesized `a ? b : c ? d : e` is not supported. Use either `(a ? b : c) ? d : e` or `a ? b : (c ? d : e)` in public_html/system/helpers/url_helper.php on line 162'

rl_helper.php

/*
php -v
PHP 8.0.28 (cli) (built: Feb 14 2023 18:33:29) ( NTS )
Copyright (c) The PHP Group
Zend Engine v4.0.28, Copyright (c) Zend Technologies
    with Zend OPcache v8.0.28, Copyright (c), by Zend Technologies

grep CI_VERSION system/core/CodeIgniter.php
        define('CI_VERSION', '3.0.0');
*/

// {{ your path }}/system/helpers/url_helper.php

if ( ! function_exists('anchor'))
{
        /**
         * Anchor Link
         *
         * Creates an anchor based on the local URL.
         *
         * @param       string  the URL
         * @param       string  the link title
         * @param       mixed   any attributes
         * @return      string
         */
        function anchor($uri = '', $title = '', $attributes = '')
        {
                $title = (string) $title;

                // original code
                // $site_url = is_array($uri) ? site_url($uri) : preg_match('#^(\w+:)?//#i', $uri) ? $uri : site_url($uri);

                // fixed code
                // https://github.com/bcit-ci/CodeIgniter/issues/3761
                // https://forum.codeigniter.com/thread-61352.html
                $site_url = is_array($uri) ? site_url($uri) : ( preg_match('#^(\w+:)?//#i', $uri) ? $uri : site_url($uri) );

                if ($title === '')
                {
                        $title = $site_url;
                }

                if ($attributes !== '')
                {
                        $attributes = _stringify_attributes($attributes);
                }

                return '<a href="'.$site_url.'"'.$attributes.'>'.$title.'</a>';
        }
}