public static function submit_tags_form($questionid, $contextid, $formdata) {
        global $DB, $CFG;

        $data = [];
        $result = ['status' => false];

        // Parameter validation.
        $params = self::validate_parameters(self::submit_tags_form_parameters(), [
            'questionid' => $questionid,
            'contextid' => $contextid,
            'formdata' => $formdata
        ]);

        $editingcontext = \context::instance_by_id($contextid);
        self::validate_context($editingcontext);
        parse_str($params['formdata'], $data);

        if (!$question = $DB->get_record_sql('
                SELECT q.*, qc.contextid
                FROM {question} q
                JOIN {question_categories} qc ON qc.id = q.category
                WHERE q.id = ?', [$questionid])) {
            print_error('questiondoesnotexist', 'question');
        }

        require_once($CFG->libdir . '/questionlib.php');
        require_once($CFG->dirroot . '/question/type/tags_form.php');

        $cantag = question_has_capability_on($question, 'tag');
        $questioncontext = \context::instance_by_id($question->contextid);
        $contexts = new \question_edit_contexts($editingcontext);

        $formoptions = [
            'editingcontext' => $editingcontext,
            'questioncontext' => $questioncontext,
            'contexts' => $contexts->all()
        ];

        $mform = new \core_question\form\tags(null, $formoptions, 'post', '', null, $cantag, $data);

        if ($validateddata = $mform->get_data()) {
            if ($cantag) {
                if (isset($validateddata->tags)) {
                    // Due to a mform bug, if there's no tags set on the tag element, it submits the name as the value.
                    // The only way to discover is checking if the tag element is an array.
                    $tags = is_array($validateddata->tags) ? $validateddata->tags : [];

                    core_tag_tag::set_item_tags('core_question', 'question', $validateddata->id,
                        $questioncontext, $tags);

                    $result['status'] = true;
                }

                if (isset($validateddata->coursetags)) {
                    $coursetags = is_array($validateddata->coursetags) ? $validateddata->coursetags : [];
                    core_tag_tag::set_item_tags('core_question', 'question', $validateddata->id,
                        $editingcontext->get_course_context(false), $coursetags);

                    $result['status'] = true;
                }
            }
        }

        return $result;
    }