ngx_conf_t args count

[Jeffrey Walton]

>From Miller's http://www.evanmiller.org/nginx-modules-guide.html, section 5.2:

ngx_http_upstream_hash(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
 {
    ngx_http_upstream_srv_conf_t  *uscf;
    ngx_http_script_compile_t      sc;
    ngx_str_t                     *value;
    ngx_array_t                   *vars_lengths, *vars_values;

    value = cf->args->elts;

    /* the following is necessary to evaluate the argument to "hash"
as a $variable */
    ngx_memzero(&sc, sizeof(ngx_http_script_compile_t));

    vars_lengths = NULL;
    vars_values = NULL;

    sc.cf = cf;
    sc.source = &value[1];
    ...
}

How does one know that value[1] is valid? Shouldn't cf->args->nelts be
checked first? Or does ngx_conf_t always have at least two options?

Related: why was value[0] not chosen?

Jeff