let change = libpijul::change::Change::deserialize(&ch, None)?;

                let change = libpijul::change::Change::deserialize(&ch, None);
                let change = match change {
                    Ok(change) => change,
                    Err(libpijul::change::ChangeError::Io(e)) => {
                        if let std::io::ErrorKind::NotFound = e.kind() {
                            let extra = if std::path::Path::new(&ch).is_relative() {
                                " Using the full path to the change file may help."
                            } else {
                                ""
                            };
                            bail!("File {} not found, and not recognised as a prefix of a known change identifier.{}", ch, extra)
                        } else {
                            return Err(e.into())
                        }
                    }
                    Err(e) => return Err(e.into())
                };

                txn.apply_change_rec(&repo.changes, &mut channel, hash)?;

                txn.apply_change_rec(&repo.changes, &mut channel, hash)?