pub fn fold_ancestors(
stored: &Revision,
incoming: &[Revision],
current: Option<&Record>,
cap: usize,
) -> Vec<Revision>Expand description
The ancestor list to persist for a record whose revision is stored,
replacing current (if any), given the ancestors the writer supplied.
dedup(incoming ∪ {current.revision} ∪ current.ancestors) − {stored},
sorted by (counter desc, hash desc) and truncated to cap. The order is
total, so every substrate persists byte-identical lists.