Module journal 

The record a run leaves before its first replacement.

Without it, a process that dies partway through a multi-file write leaves no statement of what it was doing, and the in-memory backup map that would restore it dies with the process. The journal names every destination, the digest of what was there, and the digest of what the run intends to put there, and it is written and synced before the first rename.

Recovery goes one way: back to what was there. Both writers use it, the skill install and the repository apply alike. A run that did not finish is undone whole, including its record, so the target returns to one state it was in rather than to a mixture of two. Completing forward would need a durable commit marker and a second recovery path, and the cost of rolling back instead is one re-run of a plan that is still stored under its own id.

Structs

Entry

One destination a run touches.

Journal

An open journal. Its file exists until Journal::finish removes it.

Record

What one journal file holds.

Enums

EntryState

How far one destination has got.

Constants

SCHEMA_VERSION

The journal schema this binary writes and recovers.

Functions

recover

Roll back an outstanding run, if one is there.