epiphany/crates/epiphany-render-svg/examples
Levi Neuwirth 0316160395 Phase 3 tranche 1: casting-off, K1 schema-fill, value-restoring undo
The chosen Phase-3 attack, run as two parallel waves. 829 workspace
tests pass; clippy -D warnings, fmt, and rustdoc clean; all three
spec documents build with zero undefined references.

Casting-off (epiphany-engrave/src/casting.rs, wired into the
Engraver):
- Greedy first-fit system breaking per region at measure-start
  barline columns; a measure that would overflow the content width
  starts a new system. Hard SystemBreakAt/PageBreakAt always
  honoured; soft breaks honoured unless pathological (skipped with
  the spec's warning + IrOverride-recorded decision).
- Vertical stacking from real content extents with the inter-system
  gap read from the vertical band model; page overflow starts the
  next page. World frame: pages stacked vertically, coordinates
  baked into glyphs/strokes, so the SVG renderer, hit-testing, and
  the GUI viewport are unchanged.
- Real ResolvedPage/ResolvedSystem trees (1-based page numbers,
  content bounding boxes, staves from staff-line segments, measures
  from barline columns); every chosen break appends an
  EngravingDecision with MUSCLOID EngravedBreak provenance,
  UserOverride-attributed via the new ConstrainedLayoutIR
  break_origins sidecar; staff lines split per system with
  synthesized continuation provenance.
- Break-constraint evaluation flips: satisfied iff the layout breaks
  at the slot. The two single-system tests invert deliberately
  (a hard break is now honoured; a user break is honoured and
  attributed instead of warned). Geometric constraints evaluate in
  the pre-casting spaced frame (documented).
- Page geometry is engraver-side PageGeometry (A4 portrait at an
  8 mm staff: page 105 x 148.5 staff spaces, margins 7.5, content
  90 x 133.5; arithmetic documented) — Canvas.layout_defaults has no
  graph home and is a schema-major addition (P12-I7).
  ENGRAVER_VERSION = 2. Goldens regenerated: ten_measure_single_staff
  engraves as 2 systems (viewBox 84x20.6, was 103x11);
  valid_score_rich as 3 systems; stub goldens byte-identical.

K1 schema-fill (Operation Catalog 0.4.0 -> 0.5.0, ratified first;
wire discriminants strictly appended):
- CreateStaff (24 / tag InsertStaff 24): set-union mint of a global
  Staff; CreateStaffInstance now preconditions that its referenced
  staff is live.
- SetTimeSignature (25): value-carrying meter-change LWW keyed by
  (region, resolved position); the carried TimeSignature mints
  set-union; StructuralFieldCollision on meter_sequence.
- SetTempoSegment (26): LWW keyed by (scope, resolved start) over
  the score or region tempo map; a write that would malform the map
  refuses with the appended PreconditionFailureReason 11
  (TempoMapMalformed).
- SetStaffLayout (27): LWW advisory over the staff instance's three
  inline layout fields.
- Create score/canvas remain deliberately unavailable slots: the
  root and canvas are inline singletons with no addressable object
  model (P12-K8), not force-designed.

Value-restoring undo (P11-C8 narrowed; catalog §UndoTransaction
rewritten and per-primitive undo notes updated):
- Canonical-order write chains (base-seeded) across all eleven LWW
  families. StrictInverse restores each written key to its
  chain-predecessor value iff the transaction's write is still the
  key's last writer, else refuses the whole undo with a
  TransactionConflict naming the superseder; BestEffort restores the
  still-last keys. Clean compensations are Applied; only minted-
  object tombstone repairs ride AppliedWithRepair (no new repair
  vocabulary). Mixed mint+overwrite transactions compose; strand
  guards refuse tombstoning mints still referenced by live
  non-members.
- Undo-of-undo pinned and tested: restorations are chain writes, so
  undoing the undo's transaction restores the undone value, and a
  second undo of the same transaction conflicts (absence-restores
  repeat idempotently — documented asymmetry, P12-K11).
- Permutation invariance pinned across five delivery orders; the
  convergence generators gain the new ops and a tx-then-undo flow.
- Still deferred in normative text: delete resurrection (needs a
  system-derived tag outside the ratified closed set), Transpose
  inversion (P12-K2), Cascade dependent closure.

Trackers: Binary Format companion 0.1.0 -> 0.2.0 (appended wire/tag
tables, PreconditionFailureReason 11, payload layouts, history row —
a schema-minor evolution under its own rules); nine new Pass-12 rows
(C5, K8-K11, I7-I10); core-spec OperationKind listing gains the four
kinds; revision-history rows in core spec and companion.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01NEs4aYiu8MXjdYdMxw8PTd
2026-07-02 21:55:26 -04:00
..
render_fixture.rs Phase 3 tranche 1: casting-off, K1 schema-fill, value-restoring undo 2026-07-02 21:55:26 -04:00