Trait NodeRegistry 

pub trait NodeRegistry: Send + Sync {
    // Required methods
    fn node_meta(&self, node_id: &str) -> Option<NodeMeta>;
    fn config_hash(&self, node_id: &str) -> Option<CacheKey>;

    // Provided method
    fn meta(&self, node_id: &str) -> Option<FilterMeta> { ... }
}

Registry that maps node IDs to their metadata.

The compiler needs metadata (cacheable, differentiable, schemas) but not the implementations behind it. One required accessor, answering for both kinds of node: an optional step_meta alongside a required meta is how half the schema validation came to be skipped by whichever registry forgot to override it.

Required Methods

fn node_meta(&self, node_id: &str) -> Option<NodeMeta>

A node’s contract — schemas, cacheability, effectfulness — whichever kind it is. None means the graph names a node nobody registered, which the compiler reports rather than guesses around.

fn config_hash(&self, node_id: &str) -> Option<CacheKey>

The node’s configuration identity, folded into cache keys. Required rather than derived because only the registry knows how a node’s configuration is canonicalized (Rust: canonical CBOR of fields; Python: qualname + config + source hash).

Provided Methods

fn meta(&self, node_id: &str) -> Option<FilterMeta>

The computational view, for the phases that only make sense for a filter: gradient flow, differentiable collapsing.

None for an effectful node — deliberately. Those phases ask “should a gradient pass through here”, and the answer for a step is not “no, and warn about it” but “the question does not apply”.

Implementors

impl NodeRegistry for SimpleNodeRegistry