Function create_watcher

atomic-agent/src/watcher/mod.rs:292–309

Create a [`FileWatcher`] using the best available backend. Attempts to connect to Watchman first. If Watchman is not running or the connection fails, falls back to the snapshot-based watcher. # Arguments `config` — Watcher configuration (repo root, ignore patterns) # Returns A boxed `FileWatcher` implementation. The caller does not need to know which backend was selected. # Implementation St

(config: WatcherConfig)

/// Currently returns a `FallbackWatcher` unconditionally. The Watchman
/// backend will be implemented in Phase 16.2–16.3.
pub async fn create_watcher(config: WatcherConfig) -> AgentResult<Box<dyn FileWatcher>> {
    // Watchman backend (Phase 16.2-16.3 in ATOMIC-AGENT-TASKS.md):
    //
    // When implemented, this function will attempt to connect to the Watchman
    // daemon first. If successful, it returns a WatchmanTurnWatcher that uses
    // clock + since queries for O(changed-files) detection. If Watchman is not
    // running, it falls through to the snapshot-based fallback below.
    //
    // The Watchman backend will use:
    //   - watchman_client::Connector::new().connect() for connection
    //   - client.clock() + client.query(since: ...) for turn boundary diffing
    //   - client.state_enter/state_leave("atomic-turn") for subscriber coordination
    //   - Expr::Not(DirName(".atomic")) to exclude the repo metadata directory

    // Fall back to snapshot-based watcher (always available, O(all files) per boundary)
    log::info!("Using fallback file watcher (install Watchman for faster change detection)");
    Ok(Box::new(fallback::FallbackWatcher::new(config)))
}

// Tests