Timeline

Issues #27 and #28.

deriveCandidateHints walked each check-in's whole S-card tree and its parent's, for every check-in. Shared subtrees can never pair -- an unchanged node has the same rid on both sides, so pairAgainstParent skips it -- and their blobs were already recorded at introduction, which Pass 2 relies on only as a distinct set (it compacts with dedupSortedRids). So the walk now descends lockstep and prunes any subtree whose S node is the same artifact in both. O(check-ins x tree) becomes O(check-ins x changed paths): sub-manifest loads drop 56 percent on libfossil, to near the distinct-node floor, and the ratio grows with tree size.

The visits that remain were re-inflating. contentOfEntry memoized only .delta frames, so a .zlib sub-manifest re-inflated on every visit -- which is why a pack profile is dominated by flate.Decompress.streamInner rather than by tree-walk arithmetic. PlaintextCache gains memoize_undeltaed, off by default because a linear sweep that reads each artifact once would only duplicate bytes, and opted into by this walk, which revisits.

Output is byte-identical: the wapp store hashes unchanged, and a 189,251 artifact fossil-corpus repack is a fixpoint at 176,143,384 bytes with the same 146,059 re-deltaed.

test 3495/3495, gate, dst 6x1000, e2e 718/718, git-import-e2e, git-import-cli. check-in: a89b63ad05 user: dmestas tags: sub-manifest

pickBase reconstructed each of its five candidates through the delta chain on every call, and the candidate window slides by one artifact per write, so consecutive calls re-read almost the same set. A store-owned memo cuts frame reads 49.7 percent on pack.

The memo is a LogStore field rather than a caller-owned cache threaded through pickBase and putArtifact. A memo keyed by frame offset goes stale when rollbackArtifactBatch truncates and later writes reuse those offsets, and only the store sees that happen -- a caller-owned cache would hand callers an obligation they cannot discharge. It also changes no signature.

assertBaseMemoBelowEnd enforces the invariant at all three post-open truncation sites. Removing the clear from rollbackArtifactBatch makes it fire from a general import-path test, not only its own regression test. check-in: c075a01cfa user: dmestas tags: sub-manifest

wapp import, user CPU: safe 1076s -> 540s, fast 95s -> 53s. Byte-identical output; the 14 pinned vectors are unchanged.

std.AutoHashMap(u64,u32) + Wyhash is gone. The window is now a comptime 16-byte array read through readInt, and the table is open-addressed with capacity from a bounded counter, so it is never more than half full -- that is the probe's termination argument, asserted rather than assumed.

Most of the safe-side win is not bounds checks. Wyhash.init declares a 48-byte buf as undefined, which runtime_safety poison-fills on every call, and the encoder hashed twice per position -- once for the window, once again inside the map on the resulting key. Removing the map removed both.

The probe's explicit bound sits inside `if (std.debug.runtime_safety)`: present in ReleaseSafe where it can trap, compiled out of ReleaseFast. Written unconditionally it cost 12.2% of the fast import; gated it costs nothing in either mode. check-in: bfb63af209 user: dmestas tags: sub-manifest

zit serve on the imported destination, zit clone over a real socket, then the clone compared to Git commit by commit out of its own store. Proves the packed generation is a usable repository, not merely a readable file.

The mirror fixture gains five validated pairs and an orphan look-alike, so gate 3 is exercised in both directions -- the look-alike's bytes must survive. Author and committer instants are now distinct: git's default made them equal, which left the --attribution author comparison inert, and a regression that always wrote the committer instant would have shipped green. storeHolds errors on an undecodable name instead of answering "absent" to a question it cannot ask; twenty drop-set assertions rested on that. check-in: 4a7c197abd user: dmestas tags: sub-manifest

verify_store, verify_map and after_rename_no_replace had no test; five of the eight legacy aliases were inert selectors that PUBLISH instead of failing. The boundaries are now partitioned into named classes and a gate asserts the partition covers the enum exactly, so a new boundary cannot ship an undriven fault arm.

Cancellation and child failure are exercised while generation 1 is open, with the window proven from the export stream rather than asserted in a comment. Every case asserts launched, reaped, no destination, and a fail-closed no-staging-sibling. Post-rename is inverted: the destination must survive and hold exactly the publish manifest. check-in: 67269dd361 user: dmestas tags: sub-manifest

append(gpa, try dupe(...)) evaluates the dupe first, so a growth failure inside append strands it outside the errdefer. Split into dupe, errdefer, append. checkAllAllocationFailures over mirrorDropNames, with a non-empty drop set asserted so the probe cannot pass on a run that allocated nothing. check-in: ab9a72bd10 user: dmestas tags: sub-manifest

verifyFrozen checked headers and existence -- it opened the map without reading a byte. The ordered pipeline now proves the published generation is the raw one minus exactly the candidate-only drop set: both stores reconstructed and rehashed, name sets differenced, every commit resolved and its tree flattened, tree and provenance digests recomputed, parents and attribution compared, refs and tags resolved, and the repository view derived from scratch. Each mismatch returns its own error and blocks the rename.

Eleven corruption fixtures, one per invariant, and each clause is mutation-proven: disabling it reddens its own fixture and nothing else. A clause no fixture catches is a clause that does not exist.

The ledger's strings borrow the importer, which the freeze destroys before verification runs, so the pipeline captures what it needs before the freeze rather than reading dangling memory.

Real corpus unchanged by the added checks: 7,010,160 bytes published, 0 faults, fixpoint byte-identical.

test 3484/3484, gate, e2e 716/716, git-import-e2e 11/11, git-import-cli 247/247, dst 6x1000. check-in: 60d9edab68 user: dmestas tags: sub-manifest

Translation writes a raw generation, packing writes a second through the classifier's candidate-only drop set, verification reopens both, and only the packed one is published. Stages are one-way and publish rejects every earlier state.

Measured end to end on the wapp mirror at k=5: a fresh import publishes 7.0 MB where the unpacked baseline was 63 MB. zit verify on the result reports 944 artifacts and 0 faults, a second pack is a no-op, and a second import into the same destination refuses with DEST byte-identical.

The catastrophic mode this task introduces -- the 66 MB raw generation riding the whole-directory rename into DEST -- was guarded only by statement order, since .verified is both the pre- and post-discard stage. Two guards now: publish refuses while a raw generation is present, and a staging manifest requires exactly {.zit, .zit-checkout, .zit-import-map.jsonl, refs} immediately before the sync.

Also fixes a use-after-free introduced with the S-tree hints: the partition-key map borrowed an S card's filename, which every frame below the root frees on return. The key is owned now, pinned by a pack-level test that segfaults without it.

test 3471/3471, gate, e2e 716/716, git-import-e2e 11/11, git-import-cli 234/234, dst 6x1000. check-in: 8530aa1440 user: dmestas tags: sub-manifest

deriveCandidateHints read only a check-in's F run, and an S-bearing check-in keeps its files in sub-manifests -- so a tree-shaped repository got no same-path hints at all and every blob fell back to the chronological window. Pack was almost inert on exactly the shape sub-manifests produce.

Measured on the wapp mirror imported at k=5: 66.0 MB packs to 63.9 MB before (508 re-deltaed), 7.2 MB after (1028). 89% instead of 3%. zit verify on the result: 1518 artifacts, 0 faults. Fixpoint holds -- a second pack is byte-identical.

Two lanes, per design §6: blobs take earlier same-path versions nearest-first from the shared map, unchanged in shape and now fed by the full recursive enumeration; S nodes take the PRIMARY PARENT's node under an exactly equal canonical partition key, which needs both trees walked and cannot be an offset-nearest pool -- that is the heuristic the design forbids. Check-in lineage is untouched.

Recursion is bounded by max_tree_depth; a seen-set collapses diamonds and rejects cycles. A referenced S node that will not resolve is corruption and aborts, as the design requires.

test 3461/3461, gate, e2e 716/716, git-import-e2e 11/11, dst 6x1000. check-in: 6e2fc456f8 user: dmestas tags: sub-manifest

A Fossil->Git mirror carries root manifest/manifest.uuid/manifest.tags that are not project content: wapp has 252 distinct manifest blobs across 252 commits while its native history tracks no such file. The classifier proves per commit that those bytes are reconstructible from what the import already holds, so packing can drop them.

Fail-closed and cryptographic: stripped-manifest hash equals the uuid, F cards equal the tree, P cards equal validated parents, D card equals the committer instant. A real top-level file named manifest cannot satisfy that by chance, and any inconclusive signal retains every present candidate -- never a strict subset.

Three corrections to the design, all established against the corpus: presence is per-repository (fossil's manifest setting emits each of the three independently), gate 6 must exclude every present candidate since F cards list none of them, and gate 3 must strip the sterilizer line the export appends or the uuid never matches. update.zig's manifest_paths and sterilizer are now public rather than duplicated -- it already had all three names and the exact trailer.

Measured on the pinned wapp corpus: 252/252 commits validate, drop set 512 = 252 manifest + 252 manifest.uuid + 8 distinct manifest.tags.

test 3461/3461, gate, e2e 716/716, git-import-e2e 11/11, dst 6x1000. check-in: d189b0da1d user: dmestas tags: sub-manifest

applyDirect's >= skip means a tag on a separate control artifact, rather than on the check-in manifest, depends on crosslink order; names emitBranchControls as the dependent. Also corrects branchValueOf's doc, left stale by c8c7c2696e. check-in: 941ddcb981 user: dmestas tags: sub-manifest

fast-export emits each commit once, under whichever ref reached it first, so that header was provenance and not branch. A single-branch repository imported with ZERO branches; multi-head repositories were scrambled in proportion to merge activity, which at sqlite scale read as 7,421 leaves on master under repo-state §7.2's same-branch leaf test. Issue #26.

labelBranches claims the primary's first-parent chain, then each head shallowest tip first, then inherits; emitBranchControls writes one control per segment root. Two things the plan did not anticipate: objects are folded to check-ins by hash first, because two git commits can translate to one byte-identical check-in and §5.2 allows one branch tag per rid; and controls are emitted deepest-first, because §5.3's timestamp skip would otherwise let an ancestor's propagation win over a root whose commit shares its second.

source_ref is deleted rather than demoted -- after the change it had no readers. makeBranchControl now composes the §6.2 pair through artifact.composeCommitTags instead of a lone *branch card.

Content was never affected: artifacts, parent links and tip content were always correct. Only derived branch state was wrong, which is why a full benchmark ran clean through it. Repairing an existing imported store means re-importing; check-in hashes survive, since branch state lives in separate controls.

Two pre-existing expectations were rewritten, deliberately: both demanded two active branch tags on one rid, which §5.2 forbids, and were unsatisfiable rather than merely stale.

Verified: fmt, test 3281/3281, gate, e2e 716/716, git-import-e2e 11/11, dst 6x1000. Shapes A/B/C match git branch exactly, 11/11 tip parity. check-in: 4d7a22b93c user: dmestas tags: sub-manifest

repo-state §6.1 requires reading the configured value and falling back to trunk only when main-branch is unset -- "MUST NOT assume a fixed string in the presence of an explicit setting". branchValueOf, which backs the §7.2 same-branch leaf test, used the literal.

It hid because all three uses are comparisons: when both sides fall back identically the result is unchanged. It bites when one check-in is tagged and another is not, which is the imported-repository shape -- displayed as one branch by branchOf, leaf-tested as another by branchValueOf.

The name is now a field on RepoState, set through one RepoView setter so the two readers cannot drift, with branchOf asserting its argument agrees. That assert immediately found a second source: update.zig re-read the config itself and passed a value the state never saw. It also treats an empty stored name as unset, as the view already did. check-in: c8c7c2696e user: dmestas tags: sub-manifest

An S-bearing manifest carries its files in sub-manifests, not in its own F run, so reading bare .f found none of them and every tracked path was classified `added` -- identical output whether or not anything had changed. Issue #25.

CheckinBaseline and DiffBaselineResolver now flatten first, the same step commit already performs. §5.1's "downstream MUST NOT distinguish" is exactly this: a raw .f read is how a reader opts out of the derivation seam.

Submanifest-specific, confirmed both ways: a --no-submanifests import was already clean. Not import-specific though -- any tree-shaped checkout hits it, so a clone from a tree-emitting peer would too.

Regression test asserts clean status and empty diff after materializing a tree check-in, and that a real edit still reports `edited`. check-in: 1e8c8a198d user: dmestas tags: sub-manifest

hexToDigest required exactly digest_len*2 hex characters. zit init writes the sha3-256 policy, so that looked like the only case -- but import-git opens its destination under git's sha1, naming every check-in in 40 hex. So commit rejected the parent of every imported repository and reported it corrupt on a store zit verify called clean. Issue #24.

Length now comes from the name, as artifact §7.2 allows both widths. pack.zig carried the same copy and would have dropped the primary-parent hint the same way; cmd/sync.zig's callers move to the slice form.

commitParentCorrupt now names which step failed. Collapsing an undecodable name, an absent parent and real damage into one sentence is why verify and commit could disagree with no way to tell which was right.

Reproduced on 12 commits and 40 files -- not scale-dependent, and not submanifest-specific: it fires before the S-card branch, so flat imports failed identically. Regression test commits over an imported sha1 history; mutation-proved by restoring the width check. check-in: ffea6238e6 user: dmestas tags: sub-manifest

Same source, same path, two imports: check-in manifests byte-identical once F/S/Z/P are stripped, blob provenance identical, P topology re-derived through each import's own map. check-in: 81b01a1157 user: dmestas tags: sub-manifest

Imports with sub-manifests off: flat manifests throughout and the spec-default config frame (k=0, enable off). Flat is §8.1's default shape; it is this verb's analyze-and-pin that is the deviation.

TreeFormat.Shape becomes flat | tree{k, height_max}, so flat-with-a-k and tree-without-one stop being representable and every tree-only site traps on the wrong tag. buildFlat drains the same MergedCursor, so ordering, dedup and rename/copy/delete stay single-sourced. SubmanifestChoice replaces submanifest_k from Request down to UserOptions.

Publication refuses if the store holds a SUBMANIFEST anyway, derived from work done rather than from the flag. Preflight analysis still runs under flat -- skipping it would put a second divergence inside the region the benchmark times.

Closes #23. check-in: 9b96469ae6 user: dmestas tags: sub-manifest

The latch is one-way and means 'an S reference is stored here', not 'trees are enabled'. The import set enable_submanifests and left it false, which stayed hidden only because the §7.2 gate is the disjunction of the two -- a later 'zit submanifest disable' would have left the repository advertising avoid-submanifests while holding S-bearing artifacts.

Derived from emitted_nodes, not from the k pin: an import whose sources all stay flat stores no S reference and must leave the latch false. check-in: 0b6e41e54f user: dmestas tags: sub-manifest

Additive; covers the tagged trailing block and the legacy widths. check-in: 3392ff5a3e user: dmestas tags: sub-manifest

Deletes the duplicate resolver in update.zig. The surviving path decodes S-card hashes case-insensitively per §3.5; the deleted one ran them through lowercase-only validateName and rejected a legal uppercase hash. TreeError codes mapped exhaustively rather than via else. check-in: 4a3061280e user: dmestas tags: sub-manifest

Four blocks of prose attributed to §6.4 a sentence that appears nowhere in the draft; replaced with verbatim draft text.

§6.4 requires the relative margin m to be documented, which a source comment does not discharge. `zit commit --help` now states the 15% threshold, with a test that renders drift_margin_pct and requires the help to contain it -- the prose and the constant cannot drift apart.

The config frame's trailing block carries a shape tag, so an extension a reader cannot name costs one re-scan instead of an unreadable config (login, remote and project fields included). Legacy widths still parse.

Names the §7.2 avoid-submanifests predicate: the pragma keys on the setting alone, not the armed disjunction, and that divergence is now visible at the call site.

These four land together because D's deletion and E's addition are interleaved in one region of repository.zig with no hunk boundary between them. check-in: 999efb0fd9 user: dmestas tags: sub-manifest

The auto-retune erratum was accepted and is in the draft body; these comments still said it was submitted and unapplied. Comments and one test name only. check-in: a2eb78b7be user: dmestas tags: sub-manifest

Bench now builds ReleaseSafe, which is the mode the O(store) asserts fired in, so without this the clone arm hits them at width. check-in: c1f44ba0ed user: dmestas tags: sub-manifest

ReleaseSafe asserts made the clone answer O(store), and serve's 5s deadline raced read + answer + write as one unit -- so a slow answer was cancelled mid-flight and the dead pread surfaced as error.Storage.

Asserts gone (zit verify covers them); the deadline now races read and write separately. Not scale-dependent -- machine speed vs a wall clock.

Stalled peer still cut at 5.0s. test/gate/e2e/dst green. check-in: 94bebf57f1 user: dmestas tags: trunk

The emitted `optimize` field was the string "ReleaseFast", hardcoded into the JSON format string rather than derived from anything. It reported ReleaseFast for every record the benchmark has ever written, whatever the executable was actually built as - so the one field whose job is to say which binary produced a measurement could not be wrong in a detectable way, only in a silent one.

Now `@tagName(builtin.mode)`, alongside the os/arch tags beside it that were already derived that way.

Found by switching bench to ReleaseSafe and watching `executable_sha256` change while `optimize` did not. check-in: be18ff3902 user: dmestas tags: sub-manifest

`--release` resolves to ReleaseSafe here as a correctness decision: src/ carries over a thousand asserts that turn a detected inconsistency into a crash instead of a durable write, and ReleaseFast compiles every one of them away. The bench executables opted out of that on the grounds that "a benchmark must measure optimized code".

Optimized, yes - but it has to be the code users run, or the number describes a binary nobody executes. This matters more than a uniform constant would suggest, because the cost is not uniform: the same rationale block records `zit pack` at 599 ms fast against 15.2 s safe on one store. A measurement taken in the mode that strips the asserts cannot be compared against, or used to make a claim about, the shipped artifact.

`bench_zit` is the sharpest case - the serve benchmark spawns it as the real `zit` binary, so it stood in for production while being built unlike it. check-in: 30b7d5e766 user: dmestas tags: sub-manifest

The 5s per-connection deadline raced read + answer + write as one unit, so a slow answer was indistinguishable from a stalled peer -- and cancelling mid-answer surfaced as error.Storage, telling the peer the repository was damaged. Issue #22.

Read and write are raced separately, each with the full deadline; the answer runs unraced since it is bounded by the store, not the peer.

Verified: a peer that sends one body byte and stalls is still cut at 5.0s; pikchr reclone passes. test 2327/2327, gate, e2e 671/671, dst 6x1000, fuzz serve_request_garbage. closed check-in: 73bdc2fef1 user: dmestas tags: issue22-diagnostics

Under runtime_safety (ReleaseSafe -- the shipped build) emitCloneReply reconstructed every served artifact and its delta basis just to assert a declared size. That pushed a clone round past serve's 5s per-connection deadline, which cancels mid-answer; the in-flight pread then failed and the peer got HTTP 500 on a healthy store. Issue #22.

zit verify checks the same properties on demand, which is where O(store) verification belongs.

Also names the failure server-side: serve collapses every AnswerError into a bare 500, so serveAnswer now logs which one.

Reclone verified green: wapp 1038, althttpd 1695, pikchr 2842, libfossil 17218 (18 rounds). test 2327/2327, gate, e2e 671/671, dst 6x1000. check-in: 879b867bb1 user: dmestas tags: issue22-diagnostics

crashCheckOnce repairs by truncating below the earliest injected bitflip and reopening. When the truncation empties the log, that reopen writes a fresh header - and the injected short-write fault could land on it, so open returned Storage, the sweep mapped it to Io, and the run failed. Nothing there was a statement about the store: the simulator faulted its own recovery.

The repair and its reopen now run against the healthy disk phase 2 heals to, the all-zero FaultCfg. Faults come back before the invariant check, which is workload again.

Pre-existing: trunk fails seed 201 with the same Io. check-in: 9e3107e570 user: dmestas tags: sub-manifest

The generator's own note says a real check-in DAG is acyclic by construction - a manifest's hash covers its P-card - while the phantom-parent flavor lets a hash be named before its record exists, so a later pick can close a loop and must be checked. The check only ever walked primary_parent_of, and the merge parent was drawn by pickInsertedIndex with the comment "no cycle risk".

That holds for the primary chain alone. Section 3.3 ancestry, which the B1 tie-break walks, follows merge parents too: a merge edge into an already inserted check-in, paired with a phantom primary edge out of it, closes a loop the guard never looked at. ancestryMaximal then finds every candidate dominated and no maximal element, and panics - seed 192 built exactly that, 9 to 14 to 13 and back.

parent_indices records every parent index a record names, wouldCloseCycle walks that graph visited-once, and the merge draw is checked like the primary one. A losing draw degrades to the single-parent record rather than drawing again, so the seeded stream shifts as little as it can.

Pre-existing: trunk fails seed 192 identically, and gen.zig is byte-identical there. Only the default six seeds hid it. check-in: 992ff19a23 user: dmestas tags: sub-manifest

A name can reach the same check-in through two index entries, so one selection offers the same rid twice. MtimeMaxPick.offer keeps the first as `best` and appends the second to `tied`; winner then appends `best` back, so `tied` holds that rid twice.

Ancestor sets are self-inclusive, so each copy found itself in the other's set. Dominance skipped only the same INDEX, so both copies were dominated, every candidate was eliminated, and the maximal element a finite DAG must have came up null - a panic on `best.?`, reached through resolveName.

Dominance is about being a different check-in, not sitting at a different offset. The new test drives offer/winner directly, and also pins that a duplicate cannot shadow a real descendant. check-in: d3f58d2875 user: dmestas tags: sub-manifest

Trunk's Slice 1/2 made both open paths header-only, so a rotted payload now opens clean and surfaces at content() instead of at open. The storage sweep still assumed open was the tripwire, so two of its own claims were wrong once the merge combined them with this branch's store:

- crashCheckOnce repaired only "if the open itself reports corruption", a precondition Slice 2 removed. Injected rot reached the invariant check and read as data loss. NeedsRepair, private to the harness, now carries "refused AND genuinely damaged" to the repair that already existed.

- rotWithinFrame spelled the per-frame overhead as 22, the header alone, so a frame's own trailing frame_crc32 counted as inert pad. A bitflip in those four bytes makes a reader recompute a correct checksum, compare it to a corrupted stored one, and refuse the frame; the sweep called that data loss. logstore now exports frame_fixed_overhead and the sweep derives it instead of respelling it.

Both are trunk defects, not merge damage: trunk alone fails dst at seed 8. The merge only shifted the draws far enough to reach the first one at seed 3, inside the default gate's range.

cli.zig's verb enum was the single textual conflict: a pure union of trunk's verify and this branch's submanifest and import-git.

fmt, test, gate, dst green. check-in: 584314dcb7 user: dmestas tags: sub-manifest

"the peer answered with an unexpected HTTP status" sends an investigation nowhere. 500 (the server could not build a reply), 413 (the request exceeded the body ceiling), 400 (a malformed container) and 417 (a rejected Expect: 100-continue) are four different bugs, and the message distinguished none of them. Issue #22 has been open on exactly that sentence.

transport.zig discarded the code at the status check because Zig errors carry no payload and the closed error set is deliberate. Rather than widen TransportError with a variant per status, the status is left on the Transport as last_status for the caller to read after the error, and syncRunFail names it: "the peer answered HTTP 500 (Internal Server Error)".

Immediately useful: re-running the issue #22 gate against the fossil corpus with this build turns its failure_reason from the old sentence into HTTP 500, which -- together with the reply-size arithmetic -- narrows the cause to OutOfMemory or ServerStorage and eliminates every 4xx path. The issue's own hypothesis, a per-round shun-snapshot readiness problem, is not among the candidates: that arm is documented unreachable and the code agrees.

Also corrects three comments Slice 2 falsified, all on the same read path:

logstore's open no longer CRC-verifies payloads, so the serve snapshot's contentImpl/wireImpl read faults are no longer "post-scan EIO or bitrot after a verified scan" -- ordinary stored corruption now reaches serve there, on the read. That is a better shape (one bad frame fails the round that touches it rather than making the server refuse to serve at all) but it makes that arm live traffic, and anything reasoning about how often it fires must start from that.

runPack and runShun both claimed their read-only open was an "integrity pre-flight" that aborted a corrupt source before a byte was written. It no longer verifies payloads. The guarantee still holds -- packLog pulls every artifact through srcContent, which propagates error.Corrupt rather than skipping the frame, and readFrameAt CRC-checks every read, so a rotted payload still aborts with the temp deleted and .zit untouched -- but it is now collected during the copy loop instead of at open. Both verbs RENAME OVER the original, so runPack's comment now states the consequence plainly: if srcContent is ever changed to answer null on a corrupt read, the rewrite would silently omit the damaged artifact and then delete the only copy of it.

Verified: fmt clean, test 2327/2327, gate, e2e 671/671. The new message checked against a stub server answering 500. check-in: b4637e26df user: dmestas tags: issue22-diagnostics

openReadOnly is what every CLI verb opens through, and until now it still checksummed every payload byte on every invocation -- so nothing users ran had gotten faster. It scans header-only now:

10k frames 42 MB 42.2ms -> 10.3ms 10k frames 410 MB 298.0ms -> 12.3ms 100k frames 416 MB 511.9ms -> 115.4ms 100 frames 419 MB 321.4ms -> 0.10ms

Open cost is a function of frame count rather than repository size. On a store of a few large artifacts it is effectively free.

This completes the sequence: vendor a faster crc, measure the path production actually takes, scan header-only on the append path, ship the fsck verb, then delete the eager check. Each step was gated on the one before it, and the deletion was deliberately last because it is the only one that gives something up.

What is given up: opening a repository no longer detects payload corruption. It surfaces on the read instead -- readFrameAt crc-checks every frame unconditionally now -- or on demand through "zit verify". That is the split git draws between ordinary operation and fsck, and it was signed off knowing the tradeoff. A damaged store also stays usable for everything that does not touch the damaged bytes, which the old eager check made impossible.

Slices 0 and 4 are closed too: the 4 KiB chunk widening landed inside verify, the only place that loop still runs, and the sidecar index is dead on its own gate -- the 100k-frame shape was to justify it by exceeding 150ms and came in at 119ms. mmap is dead alongside it, separately, because a mapping would keep shunned bytes resident and readable until every mapping dropped, which defeats reclamation rather than merely slowing it. Neither rejection is recorded at the logstore extension comment yet; that is the one piece of follow-up this leaves behind.

Verified on the merged tree: fmt clean, test 2327/2327, gate 19/19. On the branch tip, additionally e2e 671/671 and dst 6 seeds x 1000 steps. check-in: 6d9172d488 user: dmestas tags: trunk

The speedup reaches production. openReadOnly is the path every CLI verb takes -- Repository.open falls back to it, and Repository.logStore, the content channel behind cat, artifact, checkout and sync, calls it with no cache in front. It scanned every payload byte on every invocation:

10k frames 42 MB 42.2ms -> 10.3ms 10k frames 410 MB 298.0ms -> 12.3ms 100k frames 416 MB 511.9ms -> 115.4ms 100 frames 419 MB 321.4ms -> 0.10ms

Open cost is now a function of frame count, not repository size.

verified_on_open was the flag openReadOnly set to tell readFrameAt that the scan had already checked every frame, so reads could skip their own crc. With no scan doing that, the exemption had nothing left to rest on and the flag is deleted. readFrameAt now crc-checks unconditionally: it is the only thing standing between a rotted payload and a caller that believes it, and restoring any skip there means restoring the scan.

Detection is relocated, not removed. A payload bitflip no longer voids the open -- the rest of the repository stays usable -- and surfaces the first time anyone reads those bytes: "zit cat" and "zit artifact" both refuse with 'repository is corrupt', and "zit verify" names the artifact and the offset. That verb shipped first for exactly this reason.

openForVerify is deleted. It existed because openReadOnly both aborted on a damaged store and granted read-time trust, neither of which verify could accept; both properties are gone, it became byte-identical to openReadOnly, and its own doc comment said to remove it in this commit.

The DST prove-it-can-fail arm is inverted rather than deleted. It asserted that openReadOnly WOULD serve latent rot silently, across a seed range where at least one corpus lands a payload rot on a raw frame whose header survived. That hazard is gone, so the same range now asserts the opposite: the read path never serves rot as success. trust_on_read goes with it -- there are no longer two paths to select between. Losing the eager whole-log scan cost nothing here, because per-read verification is what was catching this all along.

Net -40 lines.

Verified: fmt clean, test 2327/2327, gate, e2e 671/671, dst 6 seeds x 1000 steps. The Slice 1 tripwire -- the assertion that openReadOnly still rejected eagerly, written to fail if the flag was deleted without an fsck verb -- fired on this commit, which is the one it was aimed at. closed check-in: b224ffeb40 user: dmestas tags: logstore-slice2

zit now imports sqlite at defaults: 36,416 commits, 2,109 refs, 44m35s, no flags. Two independent walls stood in front of that.

Refs (issue 21). One file per ref made a ref's name a path, so the filesystem got a vote on which repositories are representable. sqlite has refs/remotes/origin/EQP-improvements and .../eqp-improvements at different commits -- legal, distinct git refs -- and on APFS the second landed on the first as a bare PathAlreadyExists, raised during publication after the whole import had run. Case was only the reachable instance; path length, reserved device names and each platform's own Unicode fold table are the same bug in other clothes.

They are one sorted file now, "refs", whose lines pair a canonical name with its target. Nothing reads it back -- "refs" is a reserved root the working-tree scan skips, and branches resolve through repostate's sym- tags -- so it is interop output and its job is to be legible. Sorting makes it byte-identical for a given ref set, so two imports of one repository can be compared.

This supersedes the ASCII-fold refusal from the previous commit. That was the right interim while a ref was a filename; with one file the collision is representable, so refusing it would be gratuitous. What survives is the genuine collision -- distinct sources normalizing to a byte-identical canonical name, refs/heads/./release against refs/heads/release -- which no layout can hold, and which now names both sources instead of only failing.

Budget (issue 20). The 4 GiB payload default refused sqlite's 12.2 GiB stream, and could not simply be raised: fileCommandCeiling divided the same number, so a larger allowance for a whole history was also a larger allowance for one commit's retained command list. Those bound different things and only one is memory -- payload streams and is released per event (sqlite's import held 21 MiB), while a commit's command list is held whole. The arena has max_command_arena_bytes of its own now and keeps the old 4 GiB; the cumulative total goes to 1 TiB.

The file-command ceiling is therefore structural: about 104 million commands in one commit, and no flag raises it. Its diagnostic says so rather than pointing at a knob that no longer moves it. The help text claimed the payload flag fixed both; it only ever fixed one. check-in: 8ae7041c2c user: dmestas tags: sub-manifest

Opening a repository checksummed every payload byte, so open cost scaled with the whole store rather than with what the caller asked for. The append path now scans header-only:

10k frames 42 MB 42.2ms -> 11.2ms 10k frames 410 MB 298.0ms -> 12.7ms 100k frames 416 MB 511.9ms -> 119.2ms 100 frames 419 MB 321.4ms -> 0.10ms

openReadOnly -- the path every CLI verb reaches -- deliberately still verifies payloads. Nothing has moved on the production path yet. That is Slice 2, and it is gated on this merge's other half: zit verify, the on-demand fsck that has to exist before eager detection is removed.

The 100k-frame run settles a question the plan left open. Slice 4's gate was 'build the sidecar index only if that shape exceeds 150ms after the scan change'; it lands at 119ms. The sidecar is dead, and mmap with it -- separately, a mapping would keep shunned bytes resident and readable until every mapping dropped, which defeats the reclamation guarantee rather than merely slowing it. Both should be recorded as evaluated-and-rejected at the logstore extension comment; that is not done here.

Also adds --mode append|read-only to the open benchmark. Every open number this effort had produced measured LogStore.open, which no CLI verb enters; the two modes agreed within noise before the scan change, which is what makes the after numbers above a comparison rather than two guesses.

Verified on the merged tree: fmt clean, test 2327/2327. gate 19/19 and e2e 671/671 were watched green at the branch tip, which is content-identical -- trunk did not move between the branch point and this merge. check-in: 90bd1b8015 user: dmestas tags: trunk

Slice 2 will extend header-only scanning to openReadOnly and delete verified_on_open, which removes eager corruption detection entirely. This is the on-demand replacement that has to exist first -- the same split git makes between normal operation and git fsck.

Two passes over the store. FrameVerifier walks every frame under .verify_payloads, which is the mode the open paths are shedding; it is built on StorageFile rather than an opened LogStore, so it still works on a store that will not open -- the case an fsck exists for. Then openForVerify opens .headers_only and reconstructs each artifact, which catches a frame whose checksum is honest about bytes that are not what their name claims.

Both passes report rather than abort. A payload CRC fault carries a header-proven frame_len, so the walk steps over it and inventories the rest; only a header-window fault, whose length cannot be trusted, stops the walk. A torn tail is not a fault -- open recovers it silently, and it means an interrupted write, not rot. An unreadable payload is a finding too, not the end of the inventory.

Exit codes stay 0/1/2 as every other verb documents them; 2 remains usage error and never corruption. Findings stream to stderr as they are found, the clean summary goes to stdout, and on any fault stdout is empty.

Scope stops at content artifacts. A manifest whose bytes hash correctly is byte-identical to what commit wrote and what sync validated on ingest, so re-parsing it would catch a zit bug rather than storage rot. The help text says so.

openForVerify is deliberately not openReadOnly: openReadOnly sets verified_on_open, which makes readFrameAt skip the per-read whole-frame CRC, and it scans .verify_payloads, so on exactly the damaged store an operator is fsck-ing it aborts before pass 2 runs. Slice 2 makes the two identical and openForVerify is deleted in that commit; its doc comment says so.

The chunk buffer in scanOneFrame's payload loop widens from 4 KiB to 64 KiB, matching cloneInto's existing precedent. Post-Slice-2 that loop runs only under verify, where an operator's wall-clock is what it costs.

zit verify is not an RFC-mandated verb. repo-state 7.3 blesses full rebuild as a fallback, but the verb's shape is a local design decision, not a protocol requirement.

Verified: fmt clean, test 2327/2327, gate 19/19, e2e 671/671. Four mutants, all compiling, each red for its own semantic reason: pointing the frame pass at .headers_only, stubbing artifact.verify to true, dropping the unreadable-store tally, and reverting the payload read to a hard error. Exit arms smoke-checked against the built binary. closed check-in: bcb9f8eb6e user: dmestas tags: logstore-open-cost

sqlite carries refs/remotes/origin/EQP-improvements and .../eqp-improvements pointing at different commits. Both are legal, distinct git refs. Zit stores a ref by creating a file at its canonical path, so on APFS the second one landed on the first: bare PathAlreadyExists, raised by writeRefs during publication, after 49 minutes of completed import. No ref name, no cause.

The refusal already existed. finalizeRefs rejects two source refs that resolve to one canonical leaf -- 'refs/heads/./release' against 'refs/heads/release' is a tested case. It just compared bytes, and a filesystem does not. Keying the canonical index by an ASCII fold makes the existing rule see the collision it was written to catch, uniformly, instead of leaving it to whichever disk the import ran against.

ASCII rather than Unicode is deliberate and documented at the fold: APFS, HFS+ and NTFS each fold a different frozen table, so following them would make the importable set depend on the volume. A-Z is what they agree on.

The error now names both source refs, both canonical spellings, and whether case alone separates them -- a normalization clash and a case clash want different fixes from the operator. Retained on the importer and formatted by the CLI, the same split FileCommandOverrun uses.

This refuses on Linux what Linux tolerated, which is the point: the repository means the same thing everywhere or it is not portable. Making sqlite importable rather than merely diagnosable is a layout question -- one file per ref cannot represent it -- and stays open. check-in: f0331d2f5a user: dmestas tags: sub-manifest

The open-time scan streamed every payload byte through the crc, making open cost O(repository bytes) rather than O(what the caller asked for). ScanMode.headers_only validates each frame's header window and then steps over the payload by frameSpan arithmetic, leaving open cost O(frame count).

Measured, same binary, both modes in one run:

10k frames 42 MB 42.2ms -> 11.2ms 10k frames 410 MB 298.0ms -> 12.7ms 100k frames 416 MB 511.9ms -> 119.2ms 100 frames 419 MB 321.4ms -> 0.10ms

Every fault that lives in a header window is still caught: readFrameHeader runs unchanged, so a bad prefix crc, a bad header crc, an out-of-range hash_len and an unknown flag kind all still void the open. Torn-tail detection survives intact -- a torn frame is a clean prefix, never damaged bytes, so offset + frame_len > total catches every truncation the payload and trailer short-read checks used to, using a length the header window already proved trustworthy. What is no longer caught at open is a bitflip in already-landed payload bytes, which becomes content()'s job; it crc-checks the frame it reads regardless.

openReadOnly -- the path every CLI verb reaches -- deliberately keeps .verify_payloads. No guarantee has moved on the production path yet, and none should until the explicit fsck verb exists to replace it. This half is what makes the cost measurable without taking on that decision.

The one test that changed is the one that had to: a corrupted payload on a complete frame no longer voids open. It now asserts the fault surfaces on the first content() read AND that openReadOnly still rejects the file eagerly. That second assertion is the tripwire for deleting verified_on_open without shipping the verb first. check-in: bae910f00e user: dmestas tags: logstore-open-cost

benchOpen timed LogStore.open -- the append path. Production never takes it: Repository.open falls back to openReadOnly, and Repository.logStore, the lazy content channel behind blob, cat, checkout and sync, calls openReadOnly with no cache in front. Every open number this effort has produced described a path no CLI verb enters.

That was survivable while the two paths ran the same scan. It stops being survivable the moment either one scans header-only, at which point the bench would report the optimized path while production still paid the full cost. --mode append|read-only defaults to append so existing invocations report unchanged numbers, and the mode is in the output line because the two are only comparable when a captured log can tell them apart.

Calibration on this tree, before any scan change: the modes agree within noise on all four shapes -- run B is 1% apart. That agreement is the check that the flag measures what it claims. check-in: e56a663b7a user: dmestas tags: logstore-open-cost

ExportPayloadLimitExceeded was a bare error name. Importing sqlite cost 17 minutes to learn a single integer, and the operator still had to guess it: the stream is 12.2 GiB against a 4 GiB default.

One error carried two unrelated bounds. max_total_data is the operator's --max-export-payload-bytes; max_data is a fixed 1 GiB per-payload ceiling no flag reaches. Reporting the wrong one sends an operator to a knob that cannot help, so PayloadOverrun records which bound refused, and the single -payload arm says plainly that no option raises it.

The cumulative arm refuses to name a remedy value. Parsing stops at the overrun, so the observed total is a lower bound; 'above 9' would name a number that fails again. It reports the bound and says the full payload is larger, which is the honest shape of what the parser knows.

Also corrects the budget's own doc comment, which claimed four GiB was 'the working set an import may claim on a commodity machine'. Measured resident size importing sqlite's 12.2 GiB stream: 21 MiB. Payload is streamed and released per event. What the cumulative half actually bounds is total history, so the default over-provisions memory by three orders of magnitude while refusing a mainstream repository. check-in: ee703cde16 user: dmestas tags: sub-manifest

Trunk since d186a44e brought the repository shun table and its whole- branch verification fixes, the release-assert guard, the `test`/`gate` lane split, the structurally bounded logstore priority window, and the vendored crc32. Eight files conflicted. The decisions worth naming:

Lanes. `git-import-e2e` was a compile-only proof hanging off `test`; that is exactly the cost trunk moved to `gate`, so it moves with `e2e` and `smoke`. `import-git-bench` stays on `test` because it registers a real unit-test run rather than a compile proof. `declared_steps` is the union plus `gate`.

Sync ingest. Both sides rewrote it: trunk added the §7.7 receive-side shun admission, this branch added §7.1 phantom minting for a pushed tree's missing sub-manifests. They compose in one direction — admission is asked first, so a card §7.7 refuses is never stored and mints no phantoms either. The S references of an artifact this repository declines to hold are not names it should then go begging for.

Client construction. Trunk factored the three verbs' `Client` literal into `syncClient` and threaded `RepoAdmission`; this branch had widened `project_code` into `RepoSyncIdentity`. The helper now carries both, which is what trunk's own comment asked for: three copies of that literal is how a repository filter comes to be wired into two verbs and not the third.

Per-round server refresh. Trunk made the snapshot mandatory — `error.ServerStorage` rather than serving with no shun table — where this branch read its four sub-manifest fields through fail-open defaults. Trunk's reading wins for all six fields: serving a stale default is the failure, not the fallback.

Two guards trunk owns caught real defects in this branch's code, which is the whole point of them:

The total switch in `shunConsequence` refused to compile against the `submanifest` artifact type, exactly as its comment promised. It has an arm now.

The release-assert guard found nine asserts on untrusted input across six functions. Two were reachable faults, not style: `lookupTree` asserted §4.4 on a sub-manifest a peer supplies, so a malformed node panicked a ReleaseSafe reader and was walked anyway under `--release=fast`. It returns `SubUnresolvable` now, which §5.2 already defines as "absent, or is not a SUBMANIFEST". The empty-S-run assert became an early `null`. The two sub-manifest writers refuse an empty group through a new `SubmanifestWriteError` rather than asserting; the builder's internal path keeps its allocation-only surface through `serializeLeafCore`, since the partitioner is what establishes non- emptiness there. The rest were tautologies or restatements of invariants the card parser already enforces, and now say so in a comment instead of carrying a panic.

Verified on the merged tree: `gate`, `e2e`, `dst` (6 seeds x 1000 steps), `smoke` (S1-S10, including trunk's new shun interop), and `git- import-e2e` all green, `zig fmt --check` clean. Beyond the suite, the importer was run for real: the empty-email repro imports and its check- in carries `U mohye77`, and marktext imports end to end with the analyzed pin at k=5. check-in: 562cf5be74 user: dmestas tags: sub-manifest

zig build test was 9m13s, and the tests it actually ran were a small fraction of that: it also compiled the e2e and smoke harnesses in the pinned ReleaseSafe and then never executed them. test is now unit tests only -- 2m54s cold, 1m42s warm -- and the new gate step carries those two compile proofs.

The dst, bench and smoke UNIT tests deliberately stay on test. They are unit tests despite their siblings' names, zig build dst/smoke run the simulation and the interop check rather than them, and CI invokes the lanes one by one and never invokes gate -- so moving them would have dropped them from CI while every step still looked green. ci_test's declared_steps records gate as intentionally not-in-CI, and names that failure mode for the next lane someone adds. check-in: 7363238ad5 user: dmestas tags: trunk

std.debug.assert is right for an internal invariant and wrong for a rule about data the function did not produce, and it is wrong in two different ways. Under the ReleaseSafe default it survives and PANICS: on the write path that is the trade we want, a crash over a durable bad frame, but on a peer-reachable path it is a remote denial of service. Under an explicitly chosen --release=fast it compiles to nothing and the input flows through unvalidated. One fix, a checked error, closes both.

Flags an assert only when all of: the fn is pub, returns an error union so a rejection was already available, the assert names one of its own parameters, and no earlier return in the body already rejects on that parameter. That last rule is what makes it signal -- delta.applyCopy returns MalformedDelta and then asserts to restate it, which is the CORRECT shape and must not be flagged.

The baseline is keyed on file, function and COUNT, never on line numbers: line numbers churn on every edit above them, while a count still catches a second bad assert added to a function that already has one. It fails in both directions, so a fixed finding must be removed from the list and the list can only shrink.

Existing findings are recorded, not fixed. Triage belongs in issue 19, where the ReleaseSafe default already reduces the write-path subset to crash-instead-of-corrupt and leaves the sync-side ones as the live exposure. check-in: 949e2b5542 user: dmestas tags: trunk

src/ carries 1086 std.debug.assert calls. They are how a detected inconsistency becomes a crash instead of a durable write -- TigerStyle's 'downgrade catastrophic correctness bugs into liveness bugs' -- and that trade exists only while the assertion does. ReleaseFast and ReleaseSmall compile every one to nothing, so a binary built that way converts each guarded corruption into an unguarded one, in a store where a bad frame is permanent and a crash is not.

Measured, not assumed. Read-side verbs are indistinguishable between the two modes: status, log and stat all sit inside noise on a 5 MB store. zit pack is not: 599ms fast against 15.2s safe, about 25x, because the delta encoder's best-of-N search is a tight per-byte loop where a bounds check is a large share of the work. That argues for setRuntimeSafety(false) on that measured loop -- local, reviewable, over code the fuzz and DST lanes already cover -- rather than stripping assertions from every other path in the binary. Not taken here.

Note the option surface changes: stating a preference replaces the -Doptimize enum with a -Drelease bool, so the deliberate escape hatch is the top-level --release=fast. -Doptimize=ReleaseFast no longer parses.

ci_test pins the preference, and says that if the project ever decides to ship unchecked, the pin should be deleted in that same commit so the decision is visible in history rather than arriving as drift. check-in: 4379187a10 user: dmestas tags: trunk

gatherCandidates capped the entries ADDED from the caller's priority slice, not the elements read: a duplicate hits ridListed and continues without advancing n, so the fill check never fires and the walk runs the caller's whole array with a linear dedup scan at each step. The only thing holding that back was an assert that the slice fits the window -- and std.debug.assert compiles to nothing in ReleaseFast and ReleaseSmall, so there was no guard in exactly the build where an unbounded scan would matter.

Slicing the prefix holds in every mode, and turns an over-length slice from a precondition violation into defined behavior: accepted, tail ignored. Both callers today are inside the window either way.

Two tests, both mutation-checked against the old shape. What is NOT pinned is the duplicate-heavy case: dedup leaves the surplus slots to the chronological walk, so the candidate set is identical either way and only the count of elements read differs. That is a cost property, not a behavioral one, and no test through this API can catch it -- the header comment says so rather than letting the pair read as covering it. check-in: bfec65b1a1 user: dmestas tags: trunk

A repository-local shun table (sync SS3.3), the zit shun verb over it, and the four suppression directions the drafts require: never requested, never announced or served, an arriving copy discarded, and the bytes reclaimed on demand through the existing atomic rewrite.

Built as eight slices, each through design review, TDD, spec audit, three review lenses, mutation proof and a full gate. Reading the eight as one change afterwards found what none of them could alone: a peer-reachable assert that crashed the client on a malformed DELTASRC, and a pre-rename guard that re-stat'ed a stale handle so two concurrent rewrites could un-shun each other.

Two defects predating the feature are fixed on the way. FileStorage.sizeImpl answers from a cached watermark, so pack's tail-revalidate compared a key against the number it was derived from and could never abort -- the guard had never worked. And a malformed file card could trap the client through PendingDeltaQueue.

Format version stays 1: an older binary meets an unknown frame kind and rejects cleanly, which is what it should do with a tombstone it cannot read. No interchange surface changed -- smoke covers ten fossil 2.28 scenarios including a fossil clone of a defer-shunned store and a real fossil push of a shunned artifact.

Known and recorded, not blocking: a running zit serve keeps serving the old inode until restarted after a --force reclaim swaps generations. check-in: e57bcceadf user: dmestas tags: trunk

Read as one change rather than eight slices, which surfaced defects no per-slice review could see.

A peer could crash us. ShunSet.contains asserted its key domain while its own vtable contract promised an out-of-domain name answers false and never traps -- and a 'file HASH zz SIZE' card reached it. It is a checked rejection now, and receiveDelta refuses a DELTASRC that is not a complete artifact name before one can mint a phantom, which also closes a pre-existing PendingDeltaQueue trap on the same card.

Two rewrites could un-shun each other. rewriteAndSwap's pre-rename guard re-stat'ed the caller's handle, which after a competing rename points at the old inode -- so the guard passed and the loser silently reverted the winner. It reopens .zit by name under the temp lock now, as shunAppendRows already did.

The client snapshot lacked the masked-basis guard the serve path has, so a kept delta rooted on a shunned base could be handed out in delta form.

shun_help denied two slices that landed after it was written: it still told operators a shunned artifact is only suppressed in one direction and can be re-announced back into the store.

Also: storestat's shun rows and bytes are wired into zit stat rather than left unused, so the printed breakdown still sums to the file size; the clone-send half is relabelled an erratum candidate against SS8.1/SS8.2 instead of claiming SS9.5, which is scoped to non-clone; and three stale doc bullets now describe the code that exists. closed check-in: d9578c6c6e user: dmestas tags: shun-implementation

A DST sweep that shuns artifacts (forcing a delta base, a manifest and a mid-chain artifact across seeds), reclaims through rewriteAndSwap, and cuts the run at sampled write/sync/rename boundaries. The oracle classifies the recovered store as the PRE image or the POST image and fails on anything else.

It earns its place: deleting packLog's pre-rename fsync is caught by this sweep and by nothing else in the suite. The concurrency-guard boundary is a second, DST-shaped pin on S3's fresh-stat fix rather than first coverage, and the module header says so.

Two oracle clauses are graded honestly as tripwires, not coverage. Surviving content is re-hashed by packLog before its own commit, so a defect that would corrupt it aborts the rewrite instead and the sweep just sees the PRE image; no mutant can make that clause fire. The PRE half of the third clause is subsumed by the byte-equality check. Both are kept cheap and labelled.

rewriteAndSwap and RewriteError are now pub: the property under test is a property of that sequence and reaching it needs the seam.

faulty_dir gains fileSetLength and fileClose wrappers, deliberately ungated so no sibling sweep's cut numbering shifts.

The default dst gate grows about 11s (~9%) for 12 sampled cuts per seed. check-in: cb22503707 user: dmestas tags: shun-implementation