* test(conformance): cover artifact K, delta-lookup and delta-size requirements

Single-name lookup in a delta manifest now follows artifact-format-01 8.4 (manifest.LookupFile), Marshal writes the K ticket ID lowercase (4.7.9), and new cases cover 3.1 size limits, 3.4 checksum mismatches and date-only timestamps. AF-6.3-5 and AF-7.1-2 stay uncovered with a reason in their rows.

* test(conformance): cover artifact K, delta-lookup and delta-size requirements (review fixes) check-in: 22b3a0f06d user: [email protected] tags: main, trunk

* fix(deck): accept every Julian-day spelling of artifact-format-01 4.6.4 (#370)

Sign, exponent, leading and trailing point are now read, hex/inf/nan stay rejected, and the bound is checked after millisecond rounding as fossil does.

Tracked in #370.

* fix(deck): test the millisecond rounding bound and drop the stale gap marker (#370) check-in: 288594db14 user: [email protected] tags: main, trunk

fossil's xfer_accept_unversioned_file stores a received file under the HASH its card gave, takes only the mtime when the content is the same and newer (status 2), and stores an omitted payload as NULL with size 0; send_unversioned_file sends nothing for a name it does not hold; and the client seeds uv_tosend from rows whose hash is not NULL (sections 7.3, 8.5.1). Both sides stored a received file under a hash computed by local policy and dropped status 2 and omitted-content cards; the server answered an absent name with a tombstone; the client queued its tombstones.

uv.Receive now owns the acceptance rule, which the server and the client share instead of each re-deriving it from uv.Read, uv.Status and uv.Write. check-in: d33a37fffd user: [email protected] tags: main, trunk

deck.Parse determined an artifact's type but then checked nothing against it, so a card a type disallows, a required card left out, or a tag that breaks a per-type semantic rule all parsed.

Add deck/legality.go with fossil's manifestCardTypes table (allowed and required cards per type) and the §5.4 semantic checks: a control artifact's tags may not target itself, a technote's tags are all self-referential singletons, and a forum post carries at most one of an H or I card and at most one parent. Parse now determines the type (inferType gains the B, J and Q type-setters it was missing and falls back to a control artifact, not an empty check-in, when nothing sets a type and there is no comment or parent), then applies legality and the semantic checks. A missing Z card is now caught by the universal required-card rule.

Several internal/manifest and internal/deck tests built incomplete artifacts fossil also rejects -- a cluster with a D card, a forum post with both an H and an I card, control-shaped D/U/Z artifacts with no T card, and single-card fixtures missing their type's required cards. Frame each as a valid artifact of its type; the behavior each test pins is unchanged.

This also makes two repostate conformance cases conform: the technote with a non-self tag is now rejected at parse (not by a later isArtifact gate), and the opaque-control rebuild case. Their marks are removed in conformance/repostate_gaps_test.go. check-in: 7b8f655da6 user: [email protected] tags: main, trunk

Marshal dropped a present-but-empty C comment, N mimetype or T value, a bare P card and an empty W body, and wrote D to the millisecond and E to the second, so an artifact carrying any of those did not round-trip through Parse and Marshal.

Carry the presence of a C, N or P card, and of a T value, in unexported Deck/TagCard fields that Parse sets and Marshal reads, and re-emit the W card whenever its body is non-nil (a parsed empty body is a non-nil empty slice). The public API is unchanged: a caller that sets a non-empty value still has it marshalled. Write the D and E timestamps at their writer precision -- millisecond and second -- extended to keep whatever finer fraction the parser read, so a sub-second timestamp survives the round trip. Remove the three FuzzArtifactRoundTrip knownLosses these fixes retire. check-in: 0902561005 user: [email protected] tags: main, trunk

The parser tried only two time.Parse layouts and rewrote a lowercase t to T, so it rejected the HH:MM, timezone, hour-24, Feb-31 and negative-year forms fossil accepts via SQLite's julianday(), and it silently accepted a lowercase t separator the draft rejects.

Add deck/timestamp.go: a byte cursor that parses the date-time form (optional leading minus, YYYY-MM-DD, one or more whitespace-or-T separators, HH:MM with optional seconds and fraction, an optional Z/z or +HH:MM/-HH:MM zone), the date-only form, and a bare Julian-day number, with the exact-digit field ranges the 4.6.4 erratum scopes to those forms and the "strictly after -4713-11-24" lower bound. A lowercase t separator is rejected. time.Date normalizes the hour-24 and unchecked-day forms the way julianday() does. check-in: 127685f0f5 user: [email protected] tags: main, trunk

The parser stored F-card filenames and old-names, A-card filenames and targets, and L-card titles without the §4.6 name predicates, and never dropped a reserved repository filename.

Add deck/pathname.go with the three predicates ported from fossil: the non-strict simple-pathname check (file_is_simple_pathname_nonstrict), the well-formed wiki-name check (wiki_name_is_wellformed), and the reserved-name test (file_is_reserved_name). Apply the simple-pathname predicate to the decoded F filename and old-name and the A filename; the wiki-name predicate to the decoded L title and to an A target that is not an artifact hash; and drop a reserved F-card filename silently after the sort-order check, as fossil does. check-in: 119ef76ae9 user: [email protected] tags: main, trunk

The parser stored hash-bearing tokens without checking them, so an F, B, E, G, I, K, M, P, Q, A-source or T-target token of the wrong length or alphabet passed, and the A target and N mimetype were kept raw rather than decoded.

Validate each position against the §4.7.1 map: 40 or 64 case-insensitive hex for an artifact hash, 40 for the K-card ticket id, 32 for the R checksum. A baseline manifest now requires a hash on every F card; only a delta manifest (one with a B card) may carry a hashless deletion card. Decode the A target and the N mimetype per §4.3.1 and re-encode them on marshal, keep the other hash tokens raw, and keep only the final path component of the A filename. Reject a Q sign other than + or -, and a tag name that is entirely hex in either case.

Four internal/manifest crosslink tests built manifests fossil itself rejects -- two R cards 40 hex long (R is 32), an attachment source "abc123", and a baseline manifest with a hashless deletion card. Make those fixtures valid artifacts (32-hex R, a real source hash, the merge expressed as a delta off its primary parent so the deletion card is legal); the mlink and crosslink outcomes they assert are unchanged. check-in: 1a15366e29 user: [email protected] tags: main, trunk

The parser split card arguments with strings.Fields and strings.TrimSpace, which collapsed a repeated space, split on tab and trimmed a trailing CR, and its line reader skipped blank lines. It also gave no card a maximum arity, so an extra token was absorbed.

Replace the line reader with a scanner that mirrors fossil's next_token/next_card: tokens are separated by a single space, a card ends at LF, and tab and CR are ordinary token bytes. A blank line, an empty token between two others, a bare card where a value is required, and residue after the last card are rejected; a line ending in a space keeps a present-but-empty last value. The W card's size is parsed as leading decimal digits with an overflow guard and the body must be newline terminated. The clearsign signature trailer is matched on 29 bytes, as fossil's remove_pgp_signature does, so a mangled final dash no longer hides it.

A faithful tokenizer enforces arity intrinsically -- fossil rejects an extra token as residue once the card's fields are read -- so #267 is resolved by the same change: each card is held to its exact Table 2 (§4.2.1) token count. The card parsers now take the scanner's tokens rather than one argument string; update the J-card and U-card unit tests to the new shape and to fossil's actual verdict on a multi-space U-card (rejected, not "anonymous"). check-in: 1af61c2713 user: [email protected] tags: main, trunk

deck.VerifyZ required a Z card at the last 35 bytes, read the final byte as the Z card's LF, and rejected a too-short input, so framing failures (a missing final LF, residue after the Z card, a short or wrapper-only blob) were all reported as checksum errors. Rewrite verifyZ to mirror fossil's verify_z_card: locate the Z card, never read byte n-1, treat an absent or unparsable Z card as "continue", and error only on a present-but-wrong checksum.

Restructure Parse into visible stages: a raw framing check (non-empty, ends in LF) on the bytes before the signature wrapper is stripped; the first-card line gate (upper-case letter, space); the Z self-checksum; then the card loop, which now scans the whole content and parses the Z card as an ordinary card rather than trimming a fixed 35 bytes. A missing Z card is judged by the universal required-card rule after the loop.

Update TestVerifyZTooShort, which encoded the old reject-on-short behavior, to expect fossil's: a too-short input has the Z card absent. check-in: 7aab5bfd8e user: [email protected] tags: main, trunk

A full clone of the Fossil self-hosting repository disagreed with what canonical fossil derives from the SAME artifacts: mlink -3,351 rows, tagxref -632, plink -5, leaf -1. `fossil rebuild` on our own clone put every one of them back, so the artifact set was complete and the fault was entirely in crosslink-time derivation.

Six independent causes, each verified against `fossil rebuild` on a 67.6k-blob corpus clone:

mlink, -3,351. An mlink row records a parent-to-child TRANSITION, and a merge check-in has more than one parent. Canonical runs the same file-level diff once per parent -- primary, then each merge parent, then each cherrypick source -- and flags the extra rows isaux=1; we only ever diffed against the primary parent. add_mlink is now ported whole (internal/manifest/addmlink.go), which also brings the two passes the old code approximated: the delta-vs-delta revert/resurrect pass, and the baseline-child deletion pass with its mperm=0 delete rows. "Added by merge" (pid=-1) follows canonical's rule too -- a count over the rows a file produced, not a name lookup in the merge parents. A parent whose manifest cannot be read now yields NO rows rather than a whole tree of bogus "added" rows, and the rows are derived later from the parent's side once it arrives (linkPlinkChildren), so the result no longer depends on the order the sweep visits artifacts in.

tagxref, -612 of -632. A check-in's T-card does not have to name the check-in carrying it: `fossil merge --integrate` records the branch it closed as `T +closed <hash>` on the merge check-in itself. Canonical applies a check-in's, a control artifact's and a technote's T-cards through one code path; we applied only the self-referential ones on check-ins and none at all on technotes.

tagxref, the rest. A wiki-

or event-<id> tag's value is the W-card body measured after LEADING whitespace is skipped, not the raw card length.

Artifact identification. The sweep parses every blob in the repository, so what counts as an artifact decides which rows exist at all. Three gaps: a bare card letter with no arguments is legal (fossil's own first check-in spells its parentless-ness as a bare "P" card) and rejecting it dropped that check-in entirely; an N-card after a P-card is legal in a technote for historical compatibility, and rejecting it dropped real technote revisions with their event-<id> and bgcolor tags; and the check-in-versus-control decision turns on a comment, files or parents, which made `merge --integrate` check-ins read as control artifacts. Fossil's required-card table now gates linking (isArtifact), on both the sweep and the dephantomize cascade, so a file whose first line parses as a Z-card no longer links as a dateless check-in and a wiki revision missing its U-card no longer links at all.

plink, -5. The ancestry a check-in declares is a property of the check-in, not of what happens to be in the repository when it is crosslinked. A parent hash with no blob yet now reserves a phantom the way canonical's uuid_to_rid does, so the edge exists whether the parent arrives in a later round or never; skipping it lost the edge for good, because nothing revisits an already-linked artifact.

leaf, -1. Nothing calls leaf_rebuild() outside `fossil leaves --recompute`; the table is maintained by leaf_check() over the rids leaf_eventually_check() schedules -- each rid a branch tag lands on, plus that rid's parents. Drawing candidates from event instead both missed phantom parents (which fossil does list) and added check-ins that carry no branch tag and no ancestry (which it does not).

After: a fresh corpus clone and `fossil rebuild` of that clone agree row for row on mlink, plink, tagxref, leaf AND event -- 104,919 / 23,741 / 51,766 / 1,426 / 27,099 either way, and `fossil test-integrity` reports 0 errors.

Not addressed here: the local commit path (manifest.insertMlinks) still writes one mlink row per file rather than per change, and does not record merge-parent transitions. That is a separate divergence from the clone parity this issue is about.

Co-authored-by: Dan Mestas <[email protected]>

VerifyZ validated a control artifact by hashing everything up to the last 35 bytes and comparing against the Z card it expected to find there. When a manifest arrived PGP-clearsigned, the raw blob carried a trailing "-----BEGIN PGP SIGNATURE-----" ... "-----END PGP SIGNATURE-----" block after the Z card, so the last-35-byte window landed inside the signature framing instead of on the Z card, and verification failed. deck.Parse propagated that failure, so ~95 of Fossil's own 2007-era clearsigned check-ins could not be parsed -- and any child whose primary parent was one of them lost its parent's file tree in loadPrimaryParentFiles, cascading into all-added mlink data (~98 affected children on the real corpus).

Mirror fossil's src/manifest.c remove_pgp_signature: strip the armor header (up to the blank line that ends it) and the trailing signature block, isolating the inner content the Z card is actually computed over, then verify and parse that. The stripping is an identity on non-clearsigned input (the common case) and idempotent.

The artifact's content-addressed hash is taken over the raw blob elsewhere and is untouched by this change: a clearsigned manifest still resolves to the same UUID it always has. Verified against the real Fossil check-in 61829b07 (aku, 2007-11-29), whose raw-blob SHA-1 still equals its UUID and whose inner Z-card MD5 now validates; cross-checked byte-for-byte against fossil 2.28. check-in: c1cbd26795 user: [email protected] tags: trunk, observer/otel/v0.2.0, db/driver/ncruces/v0.3.0, db/driver/modernc/v0.3.0

* fix: emit renames as a single F-card with the "w" placeholder (#51)

buildCommitFiles seeded its working set from the parent manifest and layered vfile changes on top, but never consulted vfile.origname. A pure rename has identical content, so ScanChanges clears its chnged flag; the new name then never entered the working set while the old name carried forward from the parent, so the manifest emitted the file's content under its old pathname and dropped the rename entirely.

Drive renames off vfile.origname, mirroring canonical Fossil's manifest query (src/checkin.c:1939): applyRenames retires the old pathname and records it on the surviving new-name entry, so a rename is emitted exactly once. The unchanged-content pass then loads the blob and preserves OldName.

Serialize the rename card to match stock Fossil: force a "w" permission placeholder when a renamed file's perm would otherwise be empty, keeping the prior-name field in its 4th positional slot (src/checkin.c:1999). Thread OldName through manifest.File and storeFileBlobs so the commit path can carry it.

Verified the exact card "F greet.txt <uuid> w hello.txt" against a real fossil binary for the same rename scenario.

* fix: never emit a renamed-then-deleted file in the commit manifest

applyRenames enumerated every vfile row with origname != pathname, including rows marked deleted, and unconditionally seeded a new-name entry for them. A file that was renamed and then unmanaged therefore committed as a rename F-card under its new name. The deleted-files pass could not catch it: it only knows the file's current pathname, so deleting the new name from a map keyed on parent-manifest pathnames was a no-op and nothing retired the old name.

Canonical Fossil excludes deleted rows from its manifest query outright (WHERE NOT deleted OR NOT is_selected). Match that: a deleted renamed row now retires both names and emits nothing, keeping the existing guard that leaves the old name alone when a live vfile row has reclaimed it.

Also move the deck marshaller's prior-name field inside the UUID guard. The field is positional and only meaningful after a hash; a deletion card carrying one would serialize as "F name oldname", with the old name misread as the UUID.

Tests: rename-then-delete emits no card under either name; a rename chain that recycles a freed pathname emits both cards with the right prior names and content. check-in: 29c2c5c6f5 user: [email protected] tags: trunk

FossilEncode/FossilDecode implemented only 3 of the 8 escapes the artifact/sync format §4.3 mandates (\s, \n, \\). A field value carrying a real TAB, CR, VT, FF or NUL byte -- as canonical fossil writes it -- was mis-decoded and no longer re-marshalled to its source wire bytes, changing the artifact hash. Unrecognized escapes were also left literal instead of dropping the backslash per spec.

Add the remaining escapes (\t \r \v \f \0) to both directions and make an unrecognized escape drop its backslash, matching canonical fossil fossilize/defossilize (verified against fossil 2.28). Every caller -- A/C/H/L/J/F/T/U cards and the xfer cards -- shares these functions and gets the fix.

Closes #119 check-in: 1bfa6b2094 user: [email protected] tags: trunk

The internal/hash import was added by the #93 T-card validation fix on a branch cut before the go-libfossil module rename merged. The rename's automated rewrite only touched import lines that existed at the time, so this newly-added import kept the old path and broke go build ./... on main after both merged.

CI's go build ./cmd/libfossil/ and go test $(go list ./... | grep -v /dst) didn't catch it: go list ./... drops a package that fails to compile from its output rather than failing the command, so the broken package silently dropped out of the test run instead of failing the build. check-in: 7764ecf6ff user: [email protected] tags: trunk

* fix: J card decodes value, stores name verbatim (#90)

The J-card parser had the escape direction inverted: it decoded the field name and exposed the value with its escape sequences intact. Both the spec (4.7.8) and canonical fossil (manifest.c) do the opposite -- defossilize only the value, compare the raw name.

Swap both the parse and marshal directions so the value round-trips decoded and the name stays verbatim.

* fix: T card escape-encodes the tag name on marshal (#91)

A tag/branch name containing a space was written verbatim, so 'my branch' produced 'T *sym-my branch *' -- a structurally valid but silently wrong card that re-parses as two tokens.

Align with canonical fossil: escape-encode the name on marshal and escape-decode it on parse, leaving the target token verbatim in both directions (4.7.16). TagCard.Name now holds the decoded form, so tagOrderKey reattaches the sign without re-decoding.

* fix: enforce two skipped T-card §4.7.16 checks on parse (#93)

parseTCard validated the sign and ordering key but accepted two malformed shapes from untrusted peers:

- a name that after the sign is entirely hex digits, indistinguishable from a hash target; - a target that is neither a valid artifact hash nor the literal '*'.

Reject both with errors (never a panic). hash.IsValidHash reuses the same target check the primary uuid path uses; the '*' and non-empty guards run first since it panics on an empty string.

* fix: T card decodes and encodes the tag value (#91), guard hex names on marshal (#93)

§4.7.16 applies the same escape rule to all three T-card tokens: the name and value are escape-decoded on parse and escape-encoded on marshal, while the target is stored verbatim. Only the name was handled; the value was passed through raw in both directions.

The read side was the real damage. `fossil branch new 'my branch'` writes

T *branch * my\sbranch T *sym-my\sbranch *

so importing an ordinary fossil repo with a spaced branch name produced a branch literally named "my\sbranch" through crosslink. Verified against the fossil binary: the artifact for that command now parses to value "my branch" and re-marshals byte-for-byte identical.

Marshal also gains the mirror of the hex-only tag name check parse already enforces. Without it a caller could build and store an artifact this repository could never read back; canonical fossil never emits one either, since it prefixes branch and user tags with "sym-". check-in: 0e579e24a4 user: [email protected] tags: trunk

* Enforce card occurrence classes and intra-run ordering

The deck parser enforced card-type ordering and nothing else. Each of the 14 single-occurrence card types was handled by a case that assigned, so a second occurrence silently overwrote the first, and the repeatable types were appended with no sort check at all. draft-fossil-artifact-format-00 §4.5.1 and §4.5.2 define both rules; implement them.

Duplicate rejection covers A, B, C, D, E, G, H, I, K, L, N, R, U and W. The guard is separate from the card-type check because that check permits equal consecutive letters. F, J and M gain a strictly-ascending check against the preceding entry, T the two-level (name, target hash) rule with the full sign-prefixed name as primary key. P and Q deliberately get neither: P order is semantic — primary parent first — and Q is unordered-repeatable. P also now appends across cards instead of replacing, which is what §4.5.1 means by repeatable. Z belongs to neither class, so it is accepted with no duplicate or last-card rule; the authoritative checksum is the trailing 35 bytes VerifyZ already verified.

All four ordering checks route through one comparator, deck.Compare, which is §4.5.3: unsigned octets, locale-independent, no normalization, no case folding. §4.5.3 exists because the same ordering underlies the delta-manifest merge walk and baseline binary search of §8.2, so a second copy would resolve a delta manifest wrongly rather than merely fail validation. The F check runs on the decoded filename, per §4.5.2.

Malformed input is reported through the error return, never a panic -- these bytes arrive from peers.

Two writer-side defects surfaced, both of which let this package emit artifacts its own parser now rejects. Marshal emitted J cards in caller-supplied order while already sorting F, M and T; it now sorts them. Marshal also sorted T by the concatenation name+target, which lets the target's leading hex digit compete with the tail of a longer name and reorders tags whose names are prefixes of one another; it now uses the two-level key. The F and M sorts and the R-card file enumeration route through deck.Compare as well, the latter per §6.3.

Closes #70

* Order T cards by decoded name and type the Z payload

Review found two ways the first pass diverged from canonical fossil in the accept/reject direction.

The T ordering key used the raw wire name. §4.7.16 says the name is escape-decoded and that the primary ordering key is the full name token including its leading sign character; manifest.c defossilizes the name before the ordering compare. Because "\s" begins 0x5C and a space is 0x20, the two forms order oppositely, so a run like

T *sym-a\sb aaaa... T *sym-a-c bbbb...

is valid, fossil accepts it, and we rejected it. Branch names may contain spaces, so this is an ordinary tag, not a corner case -- the same post-decode trap already handled for F. tagOrderKey now builds the decoded key and both the parser check and the marshaller's sort call it, so the two cannot drift apart.

The Z card accepted any payload. Accepting a Z line inside the body is right -- §4.5.1 puts Z in neither occurrence class and treats an earlier Z as content covered by the final checksum -- but §4.7.19 still fixes the payload at exactly 32 hexadecimal characters. Validating nothing left an arbitrary-byte channel in an otherwise fully typed grammar and would have stored and forwarded artifacts canonical refuses. Upper-case digits are accepted, matching fossil's validate16.

Also: the T sign prefix is now checked against {+,-,*} per §4.7.16, both because canonical checks it and because an unvalidated sign byte >= 0x80 would UTF-8-expand to two bytes when the ordering key is assembled and silently corrupt the comparison. Two stale §4.7.20 citations corrected to §4.7.16, and the two-level T test gained the prefix-name case that actually distinguishes a two-level comparison from a concatenated one.

* Cite the normative grammar for the case-insensitive Z token

The Z payload's case-insensitivity was justified by inferring it from the word "hexadecimal" in §4.7.19. §6.1 states it normatively: md5-token = 32hexdig-ci, a parse-accept grammar admitting both 0-9a-f and A-F. Cite that instead, and record the split it implies -- the structural check is case-insensitive while §6.2 keeps verification byte-exact against the lowercase form.

Also soften deck.Compare's claim that the delta-manifest merge walk relies on F ordering to the future tense parse.go already uses: the merge walk is a map overlay today with no comparator to share. check-in: 5036cae392 user: [email protected] tags: trunk

* fix: distinguish absent, empty, and valued U-cards in manifest parsing

Manifest parsing collapsed a wholly absent U-card and a present-but-empty U-card into the same stored value (empty string), so every crosslink call site that wrote the check-in user into event/attachment/forumpost rows lost the distinction between "no login recorded" (should be SQL NULL) and "login explicitly blanked" (canonical fossil resolves this to the literal "anonymous" at parse time — see src/manifest.c:1008-1016).

Change deck.Deck.U from string to *string so the three states are representable: nil (absent), non-nil "anonymous" (present-empty, resolved in parseUCard the same way fossil's own parser does), and non-nil with a value (present). Resolving once in the parser means every downstream crosslink/rebuild call site can keep binding d.U directly — Go's database/sql converts a nil *string argument to SQL NULL and dereferences a non-nil one automatically, so no per-call-site special casing is needed. The type change itself makes the old ambiguous string-binding path a compile error everywhere Deck.U is constructed, closing off the drift that caused issue #29.

Added deck.Str, a small pointer-literal helper, since Go can't take the address of a string literal directly; existing tests that built Deck{U: "..."} now go through it.

* fix: review nits — whitespace U-cards, rebuild coverage, tag.AddTag, naming

Four follow-ups from review of the U-card presence fix:

- deck.parseUCard now trims args before the emptiness check, matching canonical fossil's next_token() (skips leading whitespace) and every sibling card parser in this file. Previously "U \n" stored literal whitespace instead of resolving to "anonymous". Added a whitespace-only case to TestParseUCardStates.

- Added TestRebuild_UCardPresenceStates covering the rebuild path (rebuild_manifest.go's rebuildCheckin), mirroring TestCrosslink_UCardPresenceStates. The binding site was already correct (same nil-to-NULL pointer semantics as crosslink.go) but had no dedicated regression test.

- tag.AddTag now panics on an empty opts.User, matching the panic idiom CheckinOpts.User already establishes. Previously a tag created with an empty User silently crosslinked to user=''; that asymmetry with CheckinOpts was a wart worth closing rather than documenting as intentional.

- Renamed deck.Str to deck.User: the name should say what the helper constructs (a Deck.U value), not how it's implemented (a pointer take). check-in: 527759acd5 user: [email protected] tags: trunk

libfossil is a pure-Go implementation of the Fossil SCM, reading and writing the same .fossil SQLite repository format as upstream Fossil.

This is the first public release of code that previously lived in a private repository. The module path is github.com/danmestas/libfossil and the binary is named libfossil to avoid $PATH collisions with upstream fossil.

Included: - Repo lifecycle (create, clone), checkout/checkin, timeline, merge, diff, annotate, shun, tag, branch, bisect, stash, undo/redo - Sync-over-HTTP protocol (client and handler) - Two SQLite drivers: modernc (pure Go, default) and ncruces (wasm-capable) - Observer interfaces (SyncObserver, CheckoutObserver) with an optional OpenTelemetry implementation in observer/otel (separate submodule) - Deterministic simulation testing harness with BUGGIFY fault injection - Kong-based embeddable CLI under cli/ and a standalone binary under cmd/libfossil/ check-in: f5744359d3 user: [email protected] tags: trunk