Enum DecodedLine 

pub enum DecodedLine {
    Message(Box<Message>),
    Control(Box<ControlRequest>),
    ControlCancel {
        request_id: String,
    },
    ControlResponse {
        request_id: String,
        raw: Value,
    },
    Unknown {
        type_str: String,
        raw: Value,
    },
    Malformed {
        line: u64,
        reason: String,
    },
}

A single stream-json line from the subprocess - either a regular message or a control request.

Variants

Message(Box<Message>)

An assistant/user/system/result message.

Boxed: a Message is 536 bytes and every other variant here is a fraction of that (clippy::large_enum_variant). The value is decoded once per line and moved straight into the reader, so the indirection costs one allocation and saves the enum being 536 bytes wherever a line is passed around.

Control(Box<ControlRequest>)

A control request (e.g. permission check, MCP message, hook callback).

Boxed for the same reason as Self::Message: it is 312 bytes of its own and is dispatched once and dropped.

ControlCancel

The CLI has withdrawn a previously-issued control_request - the handler matching request_id should be cancelled if still in flight. Wire shape {"type":"control_cancel_request","request_id":"..."} .

Fields

request_id: String

request_id of the control_request being withdrawn.

ControlResponse

The CLI is responding to an outbound control_request we sent (initialize, interrupt, set_permission_mode, …). These arrive on stdout and are normally consumed synchronously by the client’s outbound-control wait loop - the read-dispatch loop in the events stream returned by Client::spawn never sees them. Represented here so downstream tools (the wire-conformance replay harness, debug captures) can recognise and categorise the frame instead of mis-flagging it as Unknown.

Fields

request_id: String

request_id of the outbound control_request this responds to.

raw: Value

Full JSON payload - useful for inspection and replay.

Unknown

Forward-compat fallback: the CLI emitted a frame with an unrecognised top-level type field. Forge-sdk doesn’t crash on these - it logs a warning via tracing::warn! in the dispatch path and lets the reader continue. Callers (like the wire-conformance harness) can detect and report these explicitly by matching this variant.

type_str is the raw type field value the CLI sent; raw is the full JSON object for inspection / logging / replay. Neither is typed - by definition, we don’t know what this frame is.

Fields

type_str: String

The unrecognised type field value.

raw: Value

Full JSON payload for later inspection.

Malformed

A line that failed to decode: not valid JSON, or valid JSON that matched no message shape. Typed rather than an Err so the read loop skips the line and continues - a per-line decode failure must not end the session, the same rule Unknown applies to unknown types. The reader warns with the line number, reason and a 160-char excerpt, and answers a corrupt control_request that carries a request_id.

Fields

line: u64

1-based number of the offending line.

reason: String

Why the line failed to decode.

Trait Implementations

impl Clone for DecodedLine

fn clone(&self) -> Self

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for DecodedLine

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.