Timeline

A structural clone holds the manifests of the held set and everything they reach through B and S cards (draft-fossil-horizon-00 §5.1), so a delta manifest's baseline below C is held. Its parents were labelled by nobody: boundaryOf took the parents of K's check-ins only. The clone then classified such a parent as transit and requested it, and the origin, which withholds manifests below C, never sent it; the clone stalled with one phantom outstanding. zit's origin has the same gap (sparse.zig 758-783), and zit's author agreed the draft will define a boundary hash as an unheld parent of any manifest the clone holds. boundaryOf now labels the parents of K and of every check-in the reach holds.

The regression is the HZ-3.1-4 case for a delta manifest in K whose baseline lies below C: the clone completes, the baseline is held but not a leaf, and K's check-ins derive the dense repository's tags. check-in: f0354673e2 user: [email protected] tags: feat/horizon-cones, trunk

The origin's classification memo (draft-fossil-horizon-00 §6.2): the reference graph and each cone's classification kept per store prefix and extended by appended artifacts, recomputed in full only when an arrival was already cited. A pull after a one-artifact push on fossil-scm.org's repository answers in about 0.25 s instead of 2.7 to 4.5 s. check-in: 7dec3e4fb3 user: [email protected] tags: feat/horizon-cones, trunk

HZ-6.2-9 and HZ-6.2-10 were gaps. The new cases read, from the handler's report of what each request's classification read, that a pull over an unchanged store reads nothing, one after a commit reads what it appended, a blob after its manifest is classified alone, a parent after the child citing it forces a full read, and a cone never classified is classified without re-reading the store; and that every reply announces what a second handle with an empty memo announces. HZ-6.2-10 is partial: a horizon's first classification walks its held set's trees from the store, as zit's does.

The case list joins the horizon suite from the coverage table, leaving the horizon case files to the work in flight there. check-in: 6f8176bb93 user: [email protected] tags: feat/horizon-cones, trunk

A store crosslinked only locally has no non-artifact record until its first received artifact is crosslinked, so the first push to an origin made the memo read the whole store again. The record appearing is every version it names being named at once; those were read raw, and reading file content raw adds nothing, so the extension takes them as files and goes on. Only a version whose raw read added a record or an unreadable name still forces a full read. check-in: bdff158325 user: [email protected] tags: feat/horizon-cones, trunk

Measured on a dense 68k-artifact, 21k check-in repository, a horizon pull after a one-artifact push still spent most of its time scanning every blob's metadata to extend the memo, and a structural request extended it twice: once to place the horizon ahead of the request's transaction, unpublished, and again inside it.

An extension now carries the artifact names over and reads metadata only for the arrivals and the delta ancestors their reads expand. A structural request places its horizon in a read-only transaction of its own, a committed snapshot, and publishes that view, so the inventory finds the memo current.

TestCorpusHorizonPullAfterPush (LIBFOSSIL_CORPUS) times it: a pull after a one-artifact push goes from about 2.7s to 0.2s for a content horizon, and from about 4.4s to 0.3s for a structural one. check-in: 62ffc8ff92 user: [email protected] tags: feat/horizon-cones, trunk

Each request re-read the store to classify its cone, so a pull after a one-artifact push to a large origin cost a full read. The handler now takes each store's classification memo (one per pool DB, dropped with it) and classifies its inventory and its structural reach through a view of it. The view is published only once the request has committed and stored no artifact: the inventory classifies before received files are crosslinked, so such a view describes a store that never committed. A caller holding its own transaction (a bound DB) classifies afresh.

SparseClassified now reports what the classification read: the whole store on a full read, the arrivals on an extension, none when the memo covers the store.

A property test drives random commits in every manifest form, pushes in any order and announcements against an origin and checks, after each step, that the memo keeps exactly what a fresh classification keeps for path cones, content and structural horizons under both rules. check-in: 83f8e43ebd user: [email protected] tags: feat/horizon-cones, trunk

A go-libfossil store is not append-only: a phantom fills at its old rid, and the crosslinker can link an old artifact once what it waited on arrives. An extension by the appended and filled rids alone would miss that, so the memo counts the check-in and plink rows at or below its prefix and reads the store in full when they move other than by a fill, or when a filled phantom is the base of a stored delta (the delta was unreadable before the fill). A new check-in's mlink rows naming an old file version no longer force a full read: reading file content raw adds nothing to the facts, so only a version that did is a change. check-in: 423b5535d4 user: [email protected] tags: feat/horizon-cones, trunk

An origin re-reads its store for every horizon request: the reference facts behind the path classification and the trees of the whole held set. draft-fossil-horizon-00 §6.2 asks it to keep the classification keyed by cone digest and store prefix, extend it by the artifacts appended since, and recompute in full only when an arrival carries a name a held P, B or S card cited while it was absent.

Memo keeps the store's cone-independent references (the reference facts, the check-in graph and the dangling P/B/S names) at a prefix, and per cone digest and per horizon the classification over them. A view extends each by the appended and filled rids: the loader's decisions for those rids alone, classification of the facts' new tails, and the tree walk of the check-ins K gained. Anything other than an append or an uncited fill (a cited arrival, a deleted or phantomized row, a first tree) reads the store in full. Views are copy-on-write and reach the memo only when published, so a rolled-back request leaves nothing behind. check-in: e5bdac3d33 user: [email protected] tags: feat/horizon-cones, trunk

An origin computes K for every horizon request by reading every plink edge and held check-in from the store. draft-fossil-horizon-00 §6.2 asks it to read those references once into a graph keyed to the store prefix and extend that graph by the artifacts appended since. Graph is that graph: loaded once, extended copy-on-write by the rids that changed, and HeldSet over it equals HeldSet over the store. check-in: b1933e5f82 user: [email protected] tags: feat/horizon-cones, trunk

HZ-3.1-2: the leaves rule's cost is stated where it is chosen. HZ-3.4-2: a horizon reaches the wire only as a full hash and a rule name. check-in: c79a113e0c user: [email protected] tags: feat/horizon-cones, trunk

A client that wants to merge across live branches offline should pick the leaves rule knowingly (HZ-3.1-2). The rule holds every descendant of where each childless check-in's history meets C's, which on a repository with old unmerged branches is nearly the whole history. clone and cone store --leaves now warn once on stderr, the flag help says so, and HorizonLeaves documents the cost for library callers.

HZ-3.4-2 asks that a horizon never be a count or a date on the wire. A case records the request cards of a horizon clone and pull under both rules and asserts one pragma of a full hash and a rule name; the CLI's clone refuses a name, and its store cone resolves a branch name to the full hash first. check-in: d7a8b71b9b user: [email protected] tags: feat/horizon-cones, trunk

A sparse or horizon store of a real-sized repository rebuilds: deferred check-ins are linked after the sweep and its non-artifact record, so reference loading answers from the tables instead of reading every blob against the budget. check-in: ba1e308608 user: [email protected] tags: feat/horizon-cones, trunk

A sparse rebuild must load whole-store references once the sweep has filled the tables they are answered from, or it reads every blob raw and exceeds the reference budget. The loader is now a seam the test observes, and the corpus test checks every phantom classifies as before a rebuild. check-in: 1faf2d23c3 user: [email protected] tags: feat/horizon-cones, trunk