Method decode

atomic-agent/src/envelope.rs:254–289

Decode a `SessionEnvelope` from `HashedChange.metadata` bytes. Validates the magic prefix and schema version before deserializing. # Errors Returns `AgentError::EnvelopeCodecError` if: - The data is too short - The magic prefix doesn't match - The schema version is unsupported - Postcard deserialization fails

(data: &[u8])

    /// - The schema version is unsupported
    /// - Postcard deserialization fails
    pub fn decode(data: &[u8]) -> AgentResult<Self> {
        if data.len() < MAGIC.len() + 1 {
            return Err(AgentError::EnvelopeCodecError {
                reason: format!(
                    "data too short: {} bytes (minimum {})",
                    data.len(),
                    MAGIC.len() + 1
                ),
            });
        }

        // Check magic
        if &data[..4] != MAGIC {
            return Err(AgentError::EnvelopeCodecError {
                reason: format!("invalid magic: expected {:?}, got {:?}", MAGIC, &data[..4]),
            });
        }

        // Deserialize payload (includes schema_version field)
        let envelope: Self =
            postcard::from_bytes(&data[4..]).map_err(|e| AgentError::EnvelopeCodecError {
                reason: format!("postcard deserialize failed: {}", e),
            })?;

        // Check version from the deserialized struct
        if envelope.schema_version > SCHEMA_VERSION {
            return Err(AgentError::EnvelopeCodecError {
                reason: format!(
                    "unsupported schema version: {} (max supported: {})",
                    envelope.schema_version, SCHEMA_VERSION
                ),
            });
        }

        Ok(envelope)
    }

    /// Check whether a byte slice looks like a `SessionEnvelope`.
    ///