Function manifest_path

atomic-cli/src/commands/update.rs:170–179

Resolve the install manifest path the same way the installer does: `${XDG_STATE_HOME:-${HOME}/.local/state}/atomic/install.json`. We deliberately do NOT use `dirs::state_dir()` — that returns `None` on macOS, but install.sh writes the manifest on macOS too (via the `$HOME` fallback). We must mirror the shell behavior exactly so the router finds what the installer wrote.

(env: &dyn EnvLookup)

/// `$HOME` fallback). We must mirror the shell behavior exactly so the
/// router finds what the installer wrote.
fn manifest_path(env: &dyn EnvLookup) -> PathBuf {
    let state_dir = match env.var("XDG_STATE_HOME") {
        Some(v) if !v.is_empty() => PathBuf::from(v),
        _ => {
            let home = env.var("HOME").unwrap_or_default();
            PathBuf::from(home).join(".local").join("state")
        }
    };
    state_dir.join("atomic").join("install.json")
}

/// Determine the install source for a binary at `current_exe`.
///