Implements a total, reversible canonical byte form for the entire
epiphany_core::Score graph, unblocking the byte-level full-Score serialization
gate that M3 had to defer.
epiphany-core/src/codec.rs:
- Score::canonical_bytes() / Score::decode_canonical() with a validating
ScoreDecodeError and a forward-only Reader cursor.
- A local Codec trait with generic combinators (Option/Vec/BTreeSet/BTreeMap/
tuple) and macros (struct_codec!/cstyle_enum_codec!/unit_codec!/
catalog_id_codec!) so encode and decode stay symmetric across ~110 types
spanning graph.rs, event.rs, pitch.rs, time.rs, tempo.rs.
- Uniform form: LE integers, one discriminant byte per tagged union, u32
counts/length-prefixes, every variable-width leaf length-prefixed, raw UTF-8
for free text (so decode(encode(x)) == x for any valid score; catalog ids are
already NFC). EventArena round-trips via iter_canonical + insert.
- Two pub(crate) accessors added for the codec: EventOrderingDAG::edges_ref,
SpellingPrecedence::order_ref.
- Tests: generator-score corpus (valid_score + valid_score_rich), exotic
event/pitch variants the generators omit, distinctness, and decoder
rejection of trailing/truncated/empty bytes.
epiphany-testkit:
- roundtrip::assert_score_serialization_stable: encode the real Score, store it
as a bundle Snapshot, reopen + hash-verify, decode to an equal Score, and
assert a byte-identical re-encode.
- convergence::materialized_score builds a real ~50-bar reduce_onto
materialization for the gate.
- criterion_4_full_score_byte_roundtrip flips from #[ignore] to a live gate;
wired into the conformance suite. Docs (lib.rs, README, core DECISIONS P11-4)
updated to reflect the landed codec.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Levi Neuwirth
f5aaa96b11