Third broad-K0 subsystem group — six new value-typed ops for the score-graph
containers, reusing M1's disciplines (additive: OperationKind variants 15-20,
new apply arms + reduction methods; framework frozen). Per the project lead's
call, container deletes are EMPTY-ONLY (no cascade): a precondition NoOp unless
the container has no live children, so the caller deletes contents first.
- CreateRegion / DeleteRegion, CreateStaffInstance / DeleteStaffInstance,
CreateVoice / DeleteVoice. Creates are value-typed mints of an empty container
(set-union creation); deletes are delete-wins tombstones gated on emptiness.
- core: expose Region / StaffInstance / Voice via CanonicalValue (no new byte
layout — they already have whole-score Codec impls), with round-trip coverage.
- New PreconditionFailureReason::ContainerNotEmpty (additive discriminant 10;
encode + decode), reported when an empty-only delete hits a non-empty container.
Reduction (reduce.rs):
- Two child-existence indices, region_instances and instance_voices, drive the
emptiness checks (a voice's events are read from voice_occupancy), so the
ledger projection and the graph agree on every delete result. Populated by
seed_from_graph, the create ops, and implicit voice creation in insert_event.
- CreateStaffInstance / DeleteStaffInstance maintain the region's staff_extent so
it lists exactly the manifested staves (Chapter 5 RegionExtents); valuegen's
fresh region uses a far-future wall-clock extent so it never overlaps an
existing region in both time and staff.
Migration: v1-native (no lossy v0 predecessor) -> project/migrate by identity;
group1_and_group2_kinds_round_trip_by_identity extended to cover Group 3.
Coverage:
- testkit operation_payload + ops fuzz gen_payload emit the six kinds, so the
convergence / determinism / migration-equivalence gates exercise the
bookkeeping projection at scale.
- A reduce_onto graph test materializes a region -> staff instance -> voice
subtree (invariant-clean), asserts the empty-only delete refuses a non-empty
container with ContainerNotEmpty, and verifies an ordered teardown clears the
subtree from both graph and ledger.
Gates: build/fmt/clippy -D warnings clean; cargo test --workspace green (criterion
1 green with the new container objects in the corpus); conformance_suite scale 1
passes. Catalog sections + DECISIONS for these ops land in M2e per the staged
plan. The unrelated Agent-I working tree is left uncommitted; this commit stages
only core/ops/testkit.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Levi Neuwirth
a207077cd7