FugueGcCoordinator
Coordinator that drives tombstone GC for a Fugue CRDT replicated via Quilter, gated by the eviction-safe causal-stability barrier (ADR-003 addendum v3, #262).
Mirrors RgaGcCoordinator exactly, substituting Fugue for Rga and FugueOp.Compact for RgaOp.Compact.
Role
The Fugue op-log grows without bound unless tombstones are periodically garbage-collected, but a tombstoned Insert(I, …) cannot be purged while a concurrent Insert(J, parent=I) minted by a different author may still exist undelivered — purging I would leave J's subtree unreachable. The sound condition is causal stability, not a scalar watermark.
Quilter publishes the two version-vector quantities the barrier needs:
Quilter.cutFrontier — an atomically-published CutFrontier carrying the stable cut
Sand the frontier maxF.Quilter.deliveredLocal — this replica's own contiguous delivered VV.
Parameters
the atomically-published causal-stability cut + frontier from Quilter.cutFrontier.
this replica's contiguous delivered VV from Quilter.deliveredLocal.
called with each compaction Patch; the caller wires this to Quilter.apply so the delta propagates to all peers.
the CoroutineScope for background coroutines.