Timeline

An origin answering a horizon request never sends a cluster, even one a gimme names; an origin may name a history URL in horizon-served (horizon-history-url), which the client reports; and a merge with no peer to ask refuses whenever either side's ancestry crosses the horizon. Conflicts in the changelog and the CLI horizon tests kept both sides. leaf check-in: c4b191ed05 user: [email protected] tags: feat/horizon-cones, trunk

The horizon draft pinned at zit horizon-rfc 5d618aaeb1: an origin with no tag in force mints no seed and serves the content level, and choosing C is shown with each rule's cost (repo cone cost, Repo.HorizonCost). check-in: 77e74bd011 user: [email protected] tags: feat/horizon-cones, trunk

Draft §3.4 asks a tool that suggests a horizon to show, before the choice, what each rule would hold in check-ins and bytes. repo cone cost <check-in> prints that for descendants and leaves from the local repository, and Repo.HorizonCost returns the figures. The --horizon help of repo clone and repo cone store points to it, noting that a clone has no repository yet. check-in: 834b28d9fe user: [email protected] tags: feat/horizon-cones, trunk

The draft now says an origin mints no seed, and serves the content level, when no tag is in force at any check-in the seed would cover, since a control artifact needs a T card. HZ-5.2-2 loses its scope note and the new HZ-5.2-7 row is proven by a case that mints none, advertises horizon-served content and leaves the clone holding no seed. HZ-3.4-1 is restated as guidance for the tool; it is covered with the cost report in the next commit. check-in: 4e9dea8cc1 user: [email protected] tags: feat/horizon-cones, trunk

Annotate in a structural store marks the lines that reach the horizon and names the deepen that would show their origin (§5.5); the origin memo keeps the trees a horizon's walk reads in a bounded cache, so a second horizon over the same store reads only trees the first did not. check-in: 479cbaad12 user: [email protected] tags: feat/horizon-cones, trunk

draft-fossil-horizon-00 §6.2 asks an origin to read each structural artifact's references once per store and classify every cone over that graph. The memo did so for kinds and P, B, S and A cards, but the F cards of a horizon's trees were walked from the store by the first classification of each horizon, so a second horizon under another C or rule re-read every tree it shared with the first.

The memo now keeps, per store lineage, each manifest, baseline and node a walk read: its own F-card targets and its B and S references, so a delta manifest shares its baseline's entry. A view stages what it reads and the memo takes it on Publish, so a request that rolls back leaves nothing; a kept piece serves a view only when its rid is held at that view's prefix, and its size is charged as a read would charge it, so budgets fail where a fresh walk fails. Names are interned and the cache is capped at 64MiB with LRU eviction: fossil-scm's history names about 21M F entries, over 300MiB uncapped.

On a copy of a 21k-check-in fossil repository, horizon B (2000 check-ins back) classified after horizon A (1000 back) took 2.5-3.0s and now 1.6s, reading 995 trees instead of 1995; A is unchanged at about 1.3-1.6s. check-in: 13f8021952 user: [email protected] tags: feat/horizon-cones, trunk