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

The horizon draft re-pinned to zit horizon-rfc 24457c7dd6, the batch agreed with zit's author: the list-form merge-base query (at most two secondaries; silence when a named check-in is unknown), must-ask when either ancestry crosses the horizon, deepen refusing without a common ancestor, boundary labels over every held manifest, the seed's date and label, the structural fallback dropping the seed, and cursors voided when the leaves rule's held set grows below them. check-in: c216f38b6a user: [email protected] tags: feat/horizon-cones, trunk

Record what the re-pin changed in behavior: the list-form merge-base query and when a merge asks it, the seed's U label, the deepen refusal's remedy, and the cursor voided by a leaves-rule fork. check-in: bb5fc8ebff user: [email protected] tags: feat/horizon-cones, trunk

The re-pinned draft makes the parents of a held baseline below C boundary hashes (5.3, 6.2.2) and states the structural store's fallback for a pull or sync (6.2.5, 6.3). go-libfossil already met both; these cases check them against the final text.

A case on the delta-baseline fixture (c3 and c4 delta manifests on c2, C = c3) checks that c1, the baseline's parent, is labelled no later than the reply delivering c2 and is held as an elided phantom the clone never asks for. An interop test runs the fallback with zit both ways: zit's structural store pulls from go-libfossil serving as a horizon-ignorant peer, and go-libfossil's pulls from a zit that cannot place C; each falls back to the content horizon, discards its seed and fetches the manifests below C. The recording origin gains an ignorant mode for it. check-in: a553cc1e11 user: [email protected] tags: feat/horizon-cones, trunk

Under the leaves rule a new childless check-in forked below C can move the meeting point of its ancestry with C's deeper, and older check-ins join K together with their blobs. Those sit below every cursor the origin had handed out, so a client holding one was never told of them: the origin recorded a reclassification only when a phantom was filled (6.2.6 requires recording any change of the classification).

The origin now also voids a cursor when K holds a check-in at or below it that the held set computed over the check-ins it held through that cursor lacked (horizon.Graph.JoinedAfter, a walk bounded by rid). Like the slot walk's void it is a function of the store, so the memo and a fresh classification agree: TestHorizonMemoEqualsFresh compares them at every cursor and now requires some world to void this way, and a cursor conformance case pulls under the leaves rule across such a fork, the stale cursor answered as if absent once and the next one honoured. check-in: 2c0329ede4 user: [email protected] tags: feat/horizon-cones, trunk

The re-pinned draft's 5.8 has a deepen that finds no common ancestor of C and its target, here or at the origin, refuse and name the remedy, a fresh clone with an earlier horizon, and never move C to a check-in that is not its ancestor. Deepen already refused with ErrNoDeepenPoint and left C and the seed in place, but its message named no remedy; it now does. A conformance case covers both refusals (the origin answers -, and the origin does not answer) and checks that C, the seed and the derived state stay as they were. check-in: 7a2c0b3bc3 user: [email protected] tags: feat/horizon-cones, trunk

The re-pinned draft's 6.2.4 query is a primary and one or two secondaries, `pragma horizon-mergebase <primary> <secondary>...`, and the answer repeats the query in order and appends Fossil's pivot over the set. A two-hash query was answered as the base of a pair, so a merge into a checkout with a merge already pending could be told a base Fossil's merge would not choose. The origin now takes the list (sync.MergeBaseQuery), answers nothing when it lacks any named check-in or is asked more secondaries than a six-token card can repeat, and the client takes only an answer that repeats its query.

5.5 now has the clone ask whenever either side's ancestry crosses the horizon, not only when its own walk does: over part of the graph the common ancestor found need not be the nearest. MergeContext, given a peer, checks the ancestry of the merged-in version, the checkout and its pending plain merges (content.AncestryCrosses), asks the pivot of the merged-in version over the checkout and those merges, and merges over the answer, falling back to Merge when the origin does not answer, as zit's merge does. With two merges already pending the query cannot carry them, and asking without them would name another base, so the merge is refused before anything changes.

The deepen point's query names the target over C, as zit asks it. check-in: 78483726d9 user: [email protected] tags: feat/horizon-cones, trunk

The re-pinned draft (5.2.2) makes a seed's U card the origin's own label for the minting implementation, as zit writes zit-serve, never a user's login: a seed is a tag application no user made. The origin wrote the role name "origin"; it now writes "go-libfossil".

The seed-date case is restated to the final text: D is the latest summarized tag event rounded up to a whole second and written with no fraction, checked with an event a quarter second past the second, and the dropped clause (D strictly later than the seed replaced) is no longer asserted. The structural fallback case moves to the new 6.3 row for a store already at the structural horizon. check-in: fe7d47778e user: [email protected] tags: feat/horizon-cones, trunk

zit's horizon-rfc check-in 24457c7dd6 revises the horizon draft; the other six drafts are byte-identical at it and at 3a2df62515. Each change has its own Appendix C bullet: the seed's D card is the latest summarized tag event rounded up to a whole second with no fraction, its U card the origin's label for the minting implementation, and the strictly-later clause is dropped (5.2.2); a merge asks the origin whenever either side's ancestry crosses the horizon (5.5); a deepen with no known common ancestor of C and the target is refused naming the remedy (5.8); the merge-base query takes a list of secondaries (6.2.4); a boundary hash is a parent of any held manifest, a baseline below C included (5.3, 6.2.2); and a store already at the structural horizon falls back to the content horizon, discarding its seed, when its replies lack horizon-served structural (6.3). The 3.4 cost note changes no rule.

Restate the rows whose text changed (5.2.1, 5.2.2, 5.3, 5.6, 6.2.2, 6.2.3, 6.2.4, 6.3) and add rows for the new statements (5.3, 5.5, 5.8, 6.2.4, 6.3), so each is checked against the final text. check-in: 9a0f07fe70 user: [email protected] tags: feat/horizon-cones, trunk

The horizon draft re-pinned to zit horizon-rfc 3a2df62515, and its new rule: under either horizon a path cone elides the sub-manifest nodes no in-cone slot reaches, and an origin withholds them. Interoperates with zit at 3a2df62515 both ways. check-in: 113123abae user: [email protected] tags: feat/horizon-cones, trunk