Skip to main content

join

maw::model::join

Function join 

Source 
pub fn join(a: &PatchSet, b: &PatchSet) -> Result<JoinResult, EpochMismatch>
Expand description

Join (CRDT merge) two PatchSets that share the same base epoch.

§Precondition

Both patch-sets must share the same base_epoch. If they don’t, EpochMismatch is returned.

§Algorithm

  1. Iterate the union of all paths from both patch-sets (BTreeMap ensures sorted, deterministic order).
  2. For each path:
    • Present in only one side → take it (disjoint union).
    • Present in both, identical → keep one copy (idempotent).
    • Present in both, different → classify as compatible or conflicting.

§CRDT guarantees

  • Commutativity: join(a, b) == join(b, a) — ensured by sorting conflict sides canonically.
  • Associativity: join(join(a, b), c) == join(a, join(b, c)) — ensured by deterministic conflict detection and identical-entry collapse.
  • Idempotency: join(a, a) == a — identical entries collapse.