Struct ForkEngine 

pub struct ForkEngine;

Forks a session at a given seq, producing a new, fully self-contained child session.

Implementations

impl ForkEngine

pub async fn fork( data_dir: &Path, src_id: &str, new_id: &str, at_seq: Option<u64>, store: &SessionStore, owner: Option<&str>, ) -> Result<ForkResult, SessionError>

Fork src_id at at_seq into a caller-allocated new_id (at_seq is an exclusive upper bound — matches ReplayEngine::replay’s up_to semantics: the child receives events [0, at_seq) from the parent, plus a synthetic SessionStarted header recording forked_from). at_seq = None forks at the current end of the log (copies everything) — the default for callers with no explicit cut point (ACP’s fork_session, which has no seq parameter, and the CLI’s optional --at).

new_id is caller-supplied rather than minted internally: callers such as ACP’s do_fork_session need the id before the fork call completes (to construct the session’s LoopbackChannel/entry), and the CLI mints a fresh SessionId::generate() before calling in.

owner stamps the child row’s owner_key (#5868) — see SessionStore::record_fork.

Errors

Returns SessionError::NotFound if src_id has no session-store row, SessionError::InvalidForkPoint if at_seq exceeds the parent log’s event count, or SessionError::Io/SessionError::Db if the copy or store update fails.