nautechsystems/nautilus_trader · error

invalid `CacheConfig`

Error message

invalid `CacheConfig`

What it means

Cache::new unwraps Cache::try_new and panics with this message when the provided CacheConfig fails validation. The library requires tick and bar cache capacities to be within [1, 1_000_000]; any config outside that range (or otherwise rejected by try_new) makes construction a hard panic instead of returning a Result.

Source

Thrown at crates/common/src/cache/mod.rs:2273

        Self::new(Some(CacheConfig::default()), None)
    }
}

impl Cache {
    /// Creates a new [`Cache`] instance with optional configuration and database adapter.
    #[must_use]
    /// # Note
    ///
    /// Uses provided `CacheConfig` or defaults, and optional `CacheDatabaseAdapter` for persistence.
    ///
    /// # Panics
    ///
    /// Panics if the cache config has a tick or bar capacity outside `[1, 1_000_000]`.
    pub fn new(
        config: Option<CacheConfig>,
        database: Option<Box<dyn CacheDatabaseAdapter>>,
    ) -> Self {
        Self::try_new(config, database).expect("invalid `CacheConfig`")
    }

    /// Creates a new [`Cache`] instance with optional configuration and database adapter.
    ///
    /// # Errors
    ///
    /// Returns a [`crate::config::ConfigError`] if the cache configuration is invalid.
    pub fn try_new(
        config: Option<CacheConfig>,
        database: Option<Box<dyn CacheDatabaseAdapter>>,
    ) -> crate::config::ConfigResult<Self> {
        let config = config.unwrap_or_default();
        config.validate()?;

        Ok(Self {
            config,
            index: CacheIndex::default(),
            database,

View on GitHub (pinned to 18893faf8b)

Solutions

1. Validate the CacheConfig before passing it: ensure tick_capacity and bar_capacity are within [1, 1_000_000]
2. Use Cache::try_new instead and handle the Err to get the real validation message
3. Clamp or sanitize values read from env/config files (e.g. max(1).min(1_000_000))
4. Check the log/panic payload from try_new for which specific field was rejected

Example fix

// before
let cache = Cache::new(Some(config), database);
// after
let cache = Cache::try_new(Some(config), database).expect("valid CacheConfig");

fn is_valid_cache_config(cfg: &CacheConfig) -> bool {
    (1..=1_000_000).contains(&cfg.tick_capacity)
        && (1..=1_000_000).contains(&cfg.bar_capacity)
}

// Rust panics cannot be caught; use the fallible API instead
let cache = Cache::try_new(config, database)
    .expect("cache config rejected — check tick/bar capacities in [1, 1_000_000]");

When it happens

Trigger: Calling Cache::new(Some(config), ...) where config has tick_capacity or bar_capacity equal to 0, greater than 1_000_000, or another value rejected by CacheConfig validation inside try_new.

Common situations: Loading cache capacities from environment variables or config files without clamping; a default of 0 for 'unbounded'; copy-pasting a config from another system; hand-rolled struct construction bypassing CacheConfig builders.

Understand the failure class

Background: "Invalid value" and "allowed values are" config errors: what your library rejected and how to fix it — this error's family across 41 libraries.

Related errors

• Order {client_order_id} not found
• Position {position_id} not found
• Order for {} not found to determine position ID
• Order {client_order_id} not found in cache.
• venue-leg quantity calculation validated cumulative fills

AI-assisted analysis of nautechsystems/nautilus_trader@18893faf8b (2026-09-08). Data as JSON: /api/errors/3a317c6787c51dfa. Report an issue: GitHub.