Some(SubCommand::Checkout { tag, to_channel }) => {

            Some(SubCommand::Checkout {
                mut tag,
                to_channel,
            }) => {
                let mut tag_path = repo.path.join(libpijul::DOT_DIR);
                tag_path.push("tags");

                    libpijul::changestore::filesystem::push_filename(&mut tag_path, &h);

                } else if tag.len() < 2 {
                    bail!("Ambiguous tag hash, need at least two characters")

                    bail!("Invalid tag {:?}", tag)

                    find_tag(&mut tag_path, &tag)?

                let mut txn = repo.pristine.mut_txn_begin()?;
                tag = h.to_base32();

                let mut txn = repo.pristine.mut_txn_begin()?;

                let mut tag_path = repo.path.join(libpijul::DOT_DIR);
                tag_path.push("tags");
                libpijul::changestore::filesystem::push_filename(&mut tag_path, &h);

fn find_tag(tag_path: &mut PathBuf, tag: &str) -> Result<libpijul::Hash, anyhow::Error> {
    let (a, b) = tag.split_at(2);
    tag_path.push(a);
    let mut result = None;
    for f in std::fs::read_dir(&tag_path)? {
        let e = f?;
        let p = if let Ok(p) = e.file_name().into_string() {
            p
        } else {
            continue;
        };
        if p.starts_with(b) {
            if result.is_none() {
                result = Some(p)
            } else {
                bail!("Ambiguous tag hash");
            }
        }
    }
    if let Some(mut r) = result {
        tag_path.push(&r);
        if let Some(i) = r.find('.') {
            r.truncate(i)
        }
        let f = format!("{}{}", a, r);
        if let Some(h) = libpijul::Hash::from_base32(f.as_bytes()) {
            return Ok(h);
        }
    }
    bail!("Tag not found")
}