retrieve post slug by post_tags taxonomy

i am not sure but try this:

query_posts('category_name=". $category[0]->cat_name);
                if (have_posts()) : while (have_posts()) : the_post();
                    $posttags = get_the_tags();
                    if ($posttags) {
                        foreach($posttags as $tag) {
                            $all_tags_arr[] = array($tag->name,wp_basename(get_permalink())); 
                        }
                    }

                endwhile; endif; 

                foreach ($all_tags_arr as $cat_by_tag) {
                    $output_promotion .= "<li><a href="' . get_bloginfo('url'). "https://wordpress.stackexchange.com/" . $cat_by_tag[1] . "https://wordpress.stackexchange.com/">'. $cat_by_tag[0] .'</a></li>';
                }

                print_r($output_promotion);