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

draft-fossil-horizon-00 §5.5 has a structural clone ask the origin for the base whenever either side's ancestry crosses the horizon, even when its own walk finds a common ancestor: over part of the graph that ancestor need not be the nearest. Without a peer Checkout.Merge and Repo.Merge refused only when the walk itself crossed, and merged over a held base whose sides' ancestry crossed below it.

Both now refuse such a merge with an error matching ErrBelowHorizon that names the horizon and points to Checkout.MergeContext with a Peer; MergeContext refuses the same way when the origin does not answer. A merge whose ancestry stays above the horizon, or one given its base, still merges locally. The CLI's merge already falls back to asking the remote on ErrBelowHorizon, so it now asks in these cases too. check-in: 263de5a736 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

draft-fossil-horizon-00 §6.2.5 lets an origin append to pragma horizon-served the URL of an interface outside the protocol at which history below a horizon can be queried, and §5.5 has a client direct the user there. go-libfossil emitted the level alone and dropped any URL a reply carried.

An origin now appends its horizon-history-url setting when set. The value rides the pragma as one raw card token, so SetConfig refuses anything but a single http or https URL with a host and no white space or credentials, and the handler emits nothing for a value stored past that check. The client records a valid URL from any origin in its clone and sync results, exported additively on the public results, and the CLI's clone and cone store/deepen print it. check-in: fe06d02a12 user: [email protected] tags: feat/horizon-cones, trunk

draft-fossil-horizon-00 §5.5 requires an operation needing history below the horizon to detect the crossing and name the horizon. Annotating back past C stopped at the parent the store does not hold and credited every remaining line to the oldest version it reached, presenting a guess as an attribution.

The walk now asks content.BelowHorizon about the parent it could not load; when it lies below the structural horizon, the lines left without credit are marked BelowHorizon and reported against the horizon's check-in. The public AnnotatedLine carries the flag, and repo annotate prints such lines against ^<horizon> with one trailing note naming the horizon and repo cone deepen. A content horizon holds every manifest, so BelowHorizon never fires there; a conformance case clones both depths to show it. HZ-5.5-1 is now covered for every operation it lists. check-in: 1823fe8ca8 user: [email protected] tags: feat/horizon-cones, trunk

An origin answering a horizon-scoped request already announced no cluster in its clone, pull or sync inventory and answered req-clusters with nothing, but a gimme naming a cluster still got the cluster's file card. A horizon clone that learned a cluster's name anywhere could so still be sent one, against draft-fossil-horizon-00 §4.5 and §6.2.

The handler now drops a cluster from a gimme's answer when the request carries a horizon pragma. A new conformance case records the origin's replies to a horizon clone, pull and sync across freshly minted clusters, with and without a cursor, and to every gimme and req-clusters shape, and checks no cluster name crosses; an interop test checks zit's origin the same way. check-in: 5768a5342d user: [email protected] tags: feat/horizon-cones, trunk