Struct PreparedSave 

pub struct PreparedSave { /* private fields */ }

A detached copy of the session, taken by SessionState::prepare_save() while the caller may hold the live session lock.

Taking it is memory work only: no file, configuration or policy input is read, so nothing a caller holds can wait on a policy refresh (#1783). The copy is NOT admitted for storage yet and carries no publishable bytes. Storage admission, serialization and the commit all run in write_to_disk() / publish(), after the lock has been released.

Contract: the copy is admitted under the Gateway and project policy that are current when it is ADMITTED, not when it was prepared — no policy state is captured here. If the policy is tightened between prepare and publication, records it withholds are omitted and the admitted remainder is published. Only a change between admission and the commit refuses the whole save (SaveError::AuthorityChanged).

Implementations

impl PreparedSave

pub fn write_to_disk(self) -> Result<(), String>

Admits the detached session for storage, then writes the session data, latest pointer, compaction snapshot and project index atomically. A per-session file lock and version check make deferred saves monotonic even when background tasks finish out of order.

This is the step that reads configuration and policy inputs and the disk; run it after the live session lock has been released. Nothing is written when admission refuses the session or when the admitting authority no longer holds at the commit.

The lock has a deadline. A save that cannot get it reports that instead of waiting, because SessionState::save restores unsaved_changes on Err and the next batch tries again — whereas a caller stuck in an unbounded wait keeps whatever it holds until the other side lets go (#1783).

pub fn publish(self) -> Result<(), SaveError>

write_to_disk with the refusal classified.