Im pretty new to rust and for learning, I'm developing a Tauri desktop app similar to obsidian, the frontend has a file explorer showing the users Vault, the user can change his vault so i need some global accesible variable for all the methods in the backend that need access to the Vault. This path needs to be:

• Globally accessible across multiple Tauri commands.
• Mutable (the user can change it later).
• Thread-safe (since Tauri commands run in different threads).

Current Approach I tried using OnceCell + Mutex, but it prevents updates after the first set:

static VAULT_PATH: OnceCell<Mutex<PathBuf>> = OnceCell::new();

#[tauri::command]
fn set_vault_path(path: String) -> Result<(), String> {
    VAULT_PATH.set(Mutex::new(PathBuf::from(path)))
        .map_err(|_| "Path already initialized!".to_string())?;
    Ok(())
}

i researched and found that using global variables in rust are mostly not the best practice, but i dont know how to solve this.

Question: What is the most idiomatic and safe way to handle this in Rust + Tauri?