Function get_xname_from_xname_hostlist 

pub fn get_xname_from_xname_hostlist(
    node_vec: &[String],
    node_metadata_available_vec: &[Component],
) -> Result<Vec<String>, Error>

Filter available node metadata to only those xnames present in node_vec.

Inputs not appearing in node_metadata_available_vec are silently dropped — the caller decides whether an empty result should be an error (see from_hosts_expression_to_xname_vec, which does).

Errors

Returns Ok even when the result is empty; this helper is infallible at the parse layer.