let o = make_changelist(&repo.changes, &to_upload)?;
            let u = parse_changelist(&edit::edit_bytes(&o[..])?);
            check_deps(&repo.changes, &to_upload, &u)?;
            u

            let mut o = make_changelist(&repo.changes, &to_upload)?;
            loop {
                let d = parse_changelist(&edit::edit_bytes(&o[..])?);
                let comp = complete_deps(&repo.changes, &to_upload, &d)?;
                if comp.len() == d.len() {
                    break comp
                }
                o = make_changelist(&repo.changes, &comp)?
            }

            let o = make_changelist(&repo.changes, &to_download)?;
            let d = parse_changelist(&edit::edit_bytes(&o[..])?);
            check_deps(&repo.changes, &to_download, &d)?;

            let mut o = make_changelist(&repo.changes, &to_download)?;
            let d = loop {
                let d = parse_changelist(&edit::edit_bytes(&o[..])?);
                let comp = complete_deps(&repo.changes, &to_download, &d)?;
                if comp.len() == d.len() {
                    break comp
                }
                o = make_changelist(&repo.changes, &comp)?
            };

fn complete_deps<C: ChangeStore>(
    c: &C,
    original: &[libpijul::pristine::Hash],
    now: &[libpijul::pristine::Hash],
) -> Result<Vec<libpijul::pristine::Hash>, anyhow::Error> {
    let original_: HashSet<_> = original.iter().collect();
    let mut now_ = HashSet::new();
    let mut result = Vec::new();
    for n in now {
        // check that all of `now`'s deps are in now or not in original
        for d in c.get_dependencies(n)? {
            if original_.get(&d).is_some() && now_.get(&d).is_none() {
                result.push(d);
                now_.insert(d);
            }
        }
        now_.insert(*n);
        result.push(*n)
    }
    Ok(result)
}