Artifact Description [c88e5c31b2]

Artifact c88e5c31b2bfd41da1c5890fcf9716d979e4a3d294e5c4416bfdb8b4e9276153:

• File internal/sync/sparse_walk.go
  • 2026-10-22 12:02:50 — part of check-in [352a0d9e0b] on branch feat/horizon-cones — feat(sync): serve the content horizon and send its pragma

    A horizon store asked every peer for the whole history and threw away what fell below C on arrival, so a horizon clone cost a dense clone's bandwidth. draft-fossil-horizon-00 §6 lets the request carry the horizon and the origin restrict what it sends.

    The client sends `pragma horizon HASH RULE` after its path-cone pragmas on every clone and pull, never horizon-structural, and counts the replies that say `pragma horizon-served content` (HorizonServed on the clone and sync results, internal and public). It still classifies every reply locally, so a horizon-ignorant peer stays correct (§6.3).

    The handler reads the pragma into the request's cone and serves it through the existing keep machinery rather than a parallel path: the pull inventory's keep set drops the blobs below the horizon (via ConeReferences.HorizonBelow) and every cluster; the clone walk walks the tree of a held-set check-in only, counts a parent as sent only inside the held set, and sends every sub-manifest node at its row while sending no cluster. A crossing delta is inflated through the same sourceKept test the path cone uses, charged to the round's batch. req-clusters under a horizon answers nothing, and every reply says horizon-served content.

    A horizon store refuses, through refuseClone, a dense clone and a horizon whose held set is not inside its own, both computed over the store with horizon.Place. That is the spec's subset test; zit refuses any other C or rule. A path-only store now also refuses a horizon-only request, which keeps every path.

    Interop with zit at horizon-rfc bbd1435674 holds both ways: zit clones and pulls at a horizon from the handler, the client from `zit serve`, and each side's horizon store refuses the other's dense clone. (user: [email protected], size: 8276) [annotate] [blame] [check-ins using]

  • 2026-10-22 14:33:38 — part of check-in [84be5ad824] on branch feat/horizon-cones — Merge branch 'wip/horizon-serve' into feat/horizon-cones

    Appendix A step 3 without the cursor: the client sends pragma horizon, the origin computes the held set over its dense graph, sends only the blobs above the horizon, inflates crossing deltas, sends no cluster, answers horizon-served content and refuses what it cannot cover (§6.4). Against a horizon-ignorant origin the client requests what its clusters name, as transit (§4.5 after zit#266). Interoperates with zit both ways. (user: [email protected], size: 8276) [annotate] [blame] [check-ins using]