Fossil Corpus Brief

Purpose

This brief defines the Fossil-specific source corpus for the RFC suite. It names the authoritative and informative source surfaces, the observed-byte corpus, and the section-to-source routing that the original pack required.

Neutral workflow mechanics belong in core/. This file names the Fossil materials those mechanics operate on.

Authoritative sources

Fossil implementation and observed bytes

Treat the following as primary authority for suite content:

• src/manifest.c — structural artifact parser, card validation, card ordering, delta-manifest file-set reconstruction, and the stored-artifact inputs consumed by RepoState.
• src/tag.c — repository crosslink processing, tag-state updates, branch propagation, and leaf/open-leaf maintenance for stored structural artifacts.
• src/name.c — symbolic-name resolution and repository-derived check-in selection such as current-trunk.
• src/delta.c, src/deltacmd.c, src/deltafunc.c — delta encoding, apply logic, and related behavior.
• src/xfer.c — sync card handling, clone behavior, content transfer, authentication, pragma handling, and the protocol boundary where peers admit artifacts before deriving repository state locally.
• src/http.c — transport/request-target behavior for sync POST handling.
• src/sha1.c, src/sha3.c, src/md5.c — hash and checksum computation.
• fossil.fossil — the supplied repository, treated as observed byte ground truth.

libfossil

Treat libfossil as an additional authoritative source for artifact/card understanding and validation tooling, with one boundary:

• its src/ and associated documentation are authoritative for parsing and artifact understanding,
• it is less complete than Fossil for networking behavior,
• it may corroborate the stored-artifact shapes that feed RepoState, but it does not override Fossil's own repository-state derivation,
• use it to corroborate artifact and validation behavior, not to override Fossil sync behavior.

Informative sources

These sources help orientation and terminology but can lag the code:

• www/fileformat.wiki
• www/sync.wiki
• www/delta_format.wiki
• www/delta_encoder_algorithm.wiki
• www/hashes.md
• www/hashpolicy.wiki
• www/blockchain.md

When implementation and documentation disagree, the suite states implemented behavior and records the divergence as a Fossil-specific anomaly or reviewer note.

Claim basis

For this project, every normative claim should resolve to one of these Fossil-specific evidence forms:

• a named implementation file and function,
• the observed byte content of an artifact in fossil.fossil, confirmed by direct inspection or tool output.

Training knowledge, prior prose, and lagging wiki text may help locate source, but they are not claim bases.

Observed-byte and tool surfaces

The original pack relied on these Fossil/libfossil inspection surfaces:

• fossil artifact for raw artifact inspection by hash or symbolic name,
• fossil sql for mapping rowid to UUID before artifact lookup,
• f-aparse for single-artifact parsing and R-card confirmation,
• f-parseparty -R REPO -q for repository-wide libfossil parsing,
• f-acat for raw artifact byte extraction.

Project-specific cautions:

• Whole-repository parsers are chatty; redirect or use quiet modes when gathering evidence.
• Fossil/libfossil tools that can read stdin should be given explicit input so they do not block waiting for data.
• Do not reimplement parser, delta, or hashing logic when the Fossil or libfossil entry points already expose the behavior.

Section-to-source routing

Suite topic	Read here first
Artifact naming	src/sha1.c, src/sha3.c, plus hashed-byte handling in src/manifest.c
Artifact card syntax	card lexer and W-card framing in src/manifest.c
Structural artifact types	per-type card validation and ordering in src/manifest.c
Z-card and R-card checksums	checksum handling in src/manifest.c and src/md5.c
Hash policy	src/sha1.c, src/sha3.c, and hash-policy selection in src/manifest.c
Check-in DAG inputs	manifest parent-card parsing in src/manifest.c, then repository-state linkage/crosslink handling in src/tag.c
Crosslink and tag propagation	repository crosslink procedure and propagated tag-state maintenance in src/tag.c
Branch membership, leaves, and closed markers	derived branch/leaf state maintenance in src/tag.c
Symbolic-name resolution and current-trunk	repository name-resolution and branch-selection logic in src/name.c, corroborated by tag-state inputs from src/tag.c
Delta segments	copy/literal encoding in src/delta.c
Delta application	apply logic and absent-source behavior in src/delta.c, src/deltacmd.c, src/deltafunc.c
Sync transport	HTTP transport and sync dispatch in src/http.c and src/xfer.c
Sync cards/auth/clone/round logic	card vocabulary and protocol flow in src/xfer.c
Derived repository views after sync	artifact admission in src/xfer.c, then local repository-state derivation in src/tag.c and src/name.c
Artifact anomaly audit	manifest_parse and manifest_is_well_formed in src/manifest.c

Fossil-specific evidence shape

For this project, the smallest useful citation units are:

• file:function for implementation behavior,
• artifact hash or repository rowid/UUID for observed bytes,
• a concrete tool invocation plus verdict when behavior must be demonstrated,
• a specific wiki/document path when a lagging informative source is being contrasted with code.

Exclusions

This pack intentionally does not carry:

• environment bootstrap commands,
• machine-specific build recipes,
• neutral validation-stage policy,
• harness-specific command wrappers.

Those belong in repo-wide core or toolchain materials.