Trait Channel

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pub trait Channel: Send + Sync {
    // Required methods
    fn kind(&self) -> &'static str;
    fn merge(&self, current: Option<Value>, incoming: Value) -> Result<Value>;
    fn clone_box(&self) -> Box<dyn Channel>;

    // Provided methods
    fn allows_concurrent(&self) -> bool { ... }
    fn is_ephemeral(&self) -> bool { ... }
    fn is_tracked(&self) -> bool { ... }
    fn is_ready(&self, _current: Option<&Value>) -> bool { ... }
}

Expand description

A single named state channel: it owns the merge rule that folds an incoming update value into the channel’s current value at a superstep boundary.

Channels are object-safe and value-typed (serde_json::Value) so a ChannelSet can hold a heterogeneous map of Box<dyn Channel>. Each channel decides:

Channel::merge — how an incoming write combines with the current value.
Channel::allows_concurrent — whether two branches in the same step may both write this channel (aggregates: yes; last-value: no, see crate::TinyAgentsError::InvalidConcurrentUpdate).
Channel::is_ephemeral — whether the value is cleared at the start of the next step (one-shot channels).
Channel::is_tracked — whether the value appears in ChannelSet::snapshot and is considered part of durable state.
Channel::is_ready — barrier readiness (defaults to always ready).

Required Methods§

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fn kind(&self) -> &'static str

A short, stable kind tag used for debugging and topology export.

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fn merge(&self, current: Option<Value>, incoming: Value) -> Result<Value>

Folds incoming into the channel’s current value, returning the new value. current is None the first time the channel is written.

Takes current by value so accumulating channels (topics, barriers, message logs) can reuse the existing backing Vec/Map in place instead of cloning the entire accumulated value on every merge, which was O(existing) allocation per write.

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fn clone_box(&self) -> Box<dyn Channel>

Clones the channel into a fresh box (enables Clone for ChannelSet).

Provided Methods§

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fn allows_concurrent(&self) -> bool

Whether more than one concurrent branch may write this channel within a single superstep. Aggregates (append/fold/accumulate/barrier) return true; overwrite-style channels return false and trigger crate::TinyAgentsError::InvalidConcurrentUpdate on a same-step clash.

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