check_course_mappings_duplicates.php

<?php
// This file is part of Moodle - http://moodle.org/
//
// Moodle is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// Moodle is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.

/**
 * @author  Erlend Strømsvik - Ny Media AS
 * @license http://www.gnu.org/copyleft/gpl.html GNU Public License
 * @package auth/saml
 *
 * Authentication Plugin: SAML based SSO Authentication
 *
 * Authentication using SAML2 with SimpleSAMLphp.
 *
 * Based on plugins made by Sergio Gómez (moodle_ssp) and Martin Dougiamas (Shibboleth).
 */

// We load all moodle config and libs.
require_once(dirname(dirname(__DIR__)).'/config.php');
require_once($CFG->dirroot.'/auth/saml/locallib.php');

// Validate that the user has admin rights.
if (!is_siteadmin()) {
    die('Only admins can execute this action.');
}

$pluginconfig = get_config('auth_saml');

$coursemapping = get_course_mapping_for_sync($pluginconfig, true);

$reversecoursemapping = [];
foreach ($coursemapping as $key => $values) {
    foreach ($values as $value) {
        if (!isset($reversecoursemapping[$value])) {
            $reversecoursemapping[$value] = [];
        }
        $reversecoursemapping[$value][] = $key;
    }
}

foreach ($reversecoursemapping as $key => $values) {
    if (count($values) > 1) {
        print "Duplicate mapping <b>".$key.'</b> on Moodle courses: <b>'.implode('</b>, <b>', $values).'</b><br>';
    }
}