Method append_line

src/storage.rs:473–481

Appends one line via a single `O_APPEND` write so concurrent hook processes never interleave partial lines or lose each other's entries the way read-modify-rewrite appends do.

(path: &Path, line: &str)

    /// processes never interleave partial lines or lose each other's entries
    /// the way read-modify-rewrite appends do.
    pub fn append_line(path: &Path, line: &str) -> io::Result<()> {
        if let Some(parent) = path.parent() {
            Self::create_dir_all(parent)?;
        }
        reject_symlink_components(path, "private store file")?;
        Self::open_private(path, fs::OpenOptions::new().append(true))?
            .write_all(format!("{line}\n").as_bytes())?;
        set_private_file_permissions(path)
    }

    /// Opens `path` for writing, creating it if missing with owner-only
    /// permissions applied at create time (Unix), so a fresh file never