Levi Neuwirth
55eff00778
Four findings, all confirmed against the tree. The accept-set "deviation" was not real, and I propagated it. bundle.rs:1322 has asserted max_supported_major(OperationEnvelopeBlock) == 2 since before this packet, so the gate was always satisfiable; the privacy observation about the symbol not being re-exported is true but irrelevant, because the assertion never needed to live outside the crate. I checked the premise and not the conclusion, then reported it as verified. No re-export is needed here or by G-minor. The test now also asserts what the contract actually asked for -- that a staged block carrying either kind stamps major 0, exercising the writer-side derivation rather than the bare kind. s3 asserted effects only, though the contract required chain growth too. A mutant returning Applied while skipping WriteChain::record for an unchanged value passed it, and the damage would surface only later as an undo restoring the base instead of reporting supersession. The two identical writes now sit in different transactions and a strict undo of the first must report the second as superseding; mutation (b) kills exactly that half while the effects half stays green. s9 claimed no mutation was needed because the test is itself a reject-path exercise. That reasoning was wrong: being a reject-path test does not show the rejection is caused by the mislabeling rather than something incidental. The mutation -- a parse arm that silently accepts a mismatched shape -- was both performable and killing. core_spec grouped SetCanvasLayoutDefaults and CreateInstrument as leaves with a single layout. True only of the first. Instrument has distinct major-0/1/2 layouts and stamps major 2 unconditionally because its major-2 appends are mandatory, so it is not major 1 for the opposite reason. Split. All ten contract mutations now have observed kill evidence: s1, s2, s4, s8 and s10's row-28 half were run here alongside the four recorded earlier. s8 killed only the two pinned literal-byte vectors while 217 round-trip tests stayed green -- the 3b-i property, demonstrated rather than asserted. Gate: fmt clean, clippy 0, 1371 passed / 0 failed, conformance 8/8 and 9/9, labels 6/6, core_spec PDF 0 undefined refs, goldens byte-identical, epiphany-bundle diff empty. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01QjsEnYhm1gPpf6ii2iFxFV |
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README.md
epiphany-ops
The Epiphany concurrent semantics: the operations through which the score
graph becomes a live model, and the deterministic reduction by which a set of
operations becomes a materialized score state. Implements the normative
requirements of Chapter 6 (Semantic Operations and Concurrent Reduction) of
the core specification (spec/core_spec.pdf). This is Agent C's crate per
spec/QUICKSTART.md, building on Agent A's epiphany-determinism and Agent B's
epiphany-core.
A score's state is defined by the set of operations committed to it. Any materialized graph is a deterministic reduction of that set; caches, snapshots, and partial reductions are acceleration structures, never the source of truth. — Chapter 6, Design Principles
The thesis in one paragraph
The replicated operation set is a grow-only CRDT: replicas accumulate envelopes and converge on the same set. The materialized graph is not a CRDT — it is the deterministic reduction of that set in a single canonical order (causal-first, then the HLC tuple). Any permutation of the same envelopes reduces to byte-identical materialized state. That property is the determinism heart of the architecture, and the reduction fuzzer is its tripwire.
What's here
| Area | Items | Spec |
|---|---|---|
| Stamps | HybridLogicalClock, OperationStamp, the reduction & monotonicity tuples |
Ch. 6 §"Operation Identity and Stamps" |
| Causal context | CausalContext (dotted version vector), covers, the missing-predecessor signal |
Ch. 6 §6.2 |
| Payloads | OperationKind, the discriminator-only OperationKindTag, OperationPayload, the §6.10 representative ops |
Ch. 6 §"Operation Envelopes", §6.10 |
| Envelopes | OperationEnvelope, EnvelopeHash (MUSCENVH), well_formed (incl. stamp.id == id) |
Ch. 6 §6.4 |
| Slots | OperationSlot::{Single, Equivocated}, the order-independent (Pass-10) transitions |
Ch. 6 §6.5 |
| Anomalies | AnomalousReplicaSegment, IntegrityAnomaly/Kind, the HLC-monotonicity detector |
Ch. 6 §6.6; Ch. 5 §"System-Derived Counter Collisions" |
| Effects | OperationEffect, NoOpReason, the typed PreconditionFailureReason, RepairRecord/RepairKind |
Ch. 6 §6.3.2, §6.5 |
| Conflicts | ConflictRecord, ConflictKind, content-derived ConflictId (derive_conflict_id), the registry, resolution |
Ch. 6 §6.4 |
| Transactions / undo | TransactionDescriptor with the causal-prior-descriptor rule, UndoTransactionPayload / UndoPolicy |
Ch. 6 §6.6, §6.8 |
| Operation set | OperationSet: accept pipeline (well-formedness → slot → causal), grow-only |
Ch. 6 §"Envelope Acceptance" |
| Reduction | canonical_reduction_order (single function), MaterializedState, the reduction driver |
Ch. 6 §6.3 |
The determinism this crate enforces
- A single reduction-order function.
canonical_reduction_orderperforms deterministic causal topological ordering, using the intrinsic stamp tuple(physical, logical, replica, counter)only among ready operations. - Order-independent equivocation. A duplicate
OperationIdwith different canonical bytes transitions its slot toEquivocatedregardless of which envelope arrived first (Pass 10). Equivocated slots contribute nothing to reduction; dependents are held pending. - Content-derived facts.
ConflictIdandIntegrityAnomalyIdare derived from content, so two replicas reducing the same set agree on every conflict and anomaly id — the conflict registry and anomaly register are deterministic materialized facts, not local bookkeeping. - Byte-identical materialized state.
MaterializedState::canonical_bytesserializes the effect log, conflict registry, anomaly register, object existence, spellings, and LWW fields in their normative orders. - Real graph materialization.
OperationSet::reduce_onto(&base_score)returnsGraphMaterialization { state, score }. The graph is mutated in the same canonical order and compares by canonical event identity, independent of arena storage order.
Hand-off gates
Run the gate harnesses (QUICKSTART, Agent C):
cargo test -p epiphany-ops
cargo run --release -p epiphany-ops --example fuzz_reduction # 10k iters, seed 0
cargo run --release -p epiphany-ops --example fuzz_reduction 100000 7 # soak, seed 7
- Reduction determinism — every randomized envelope set reduces to byte-identical materialized state under any acceptance order (v0 acceptance criteria 1 and 5).
- Equivocation order-independence — every duplicate-id-with-different-bytes scenario equivocates regardless of arrival order (v0 acceptance criterion 3).
The integration tests (tests/concurrent_reduction.rs) exercise these plus
transaction atomicity, descriptor precedence, anomaly exclusion, and forward
undo through the public API.
Scope and decisions
Chapter 6 specifies the framework and a representative selection of
operations; the full ~60–80-primitive catalog is an explicit open question
(§6.11) deferred to the Operation Catalog companion. This crate implements the
framework in full and the representative operations, which is sufficient to
exercise every reduction discipline. The representative operations can also
reduce onto an epiphany_core::Score: insert/delete, voice promotion, supported
cross-cutting structures, system breaks, migration checks, transaction
rollback, and undo mutate the real graph while preserving Agent B's invariants.
reduce() remains the base-free CRDT/bookkeeping API; reduce_onto() is the
graph-aware editing path. See DECISIONS.md for remaining payload boundaries.
Per QUICKSTART "Don't do these": undo is the spec's forward compensating
operation, never inverse-based; unsafe is forbidden; everything is sync.