[altvnk]

Reviewed — user-approved harness-only scope

Head: 2efc98e06, based on authoritative upstream/main 7935b4c09b72a341a8e994c0f27d57f7a0f0b97f.

• Adds six new, explicitly defined affine degree-1 B-spline/cache fixtures. Uses real native cache construction, SmSurfaceHierarchyElement::ExpandHierarchy, and SmGrid::AddElement with validated cache-owned node ordinals.
• Rust uses existing cache/grid ports and the existing leaf evaluator. No kernel, grid, cache-builder, shared protocol, or ray-tracer production edits.
• Unit-local observations compare cache leaf order, stable input surface identities, surface-pool order, ordered voxel/hierarchy membership, registration boxes/spheres, UV domains, node boxes, pseudo/polar boxes, midpoint, DU/DV and normal.
• Adds canonical-CI controls for omitted expansion with success statuses retained, wrong identity between identical surfaces, corrupted normals, invalid ownership/node selection, and continued legacy deferral.

Preserved invariants

Static checks establish that fixtures/geom.grid/cases.json and the complete legacy generator region are byte-identical to the base. All 15 old fixtures and 600 old generated inputs remain. Legacy opcodes keep their opaque semantics: the original object-7 and node-0 cases are not fixed and must remain deferred. No tolerance, absolute floor, existing output, generator, or unit status is changed. Merged #612 / closed #607 remain untouched.

Canonical CI 39964563449 completed successfully on exact head 2efc98e065f92d852dd0cb7e0449a583cb1d19ae (all seven jobs).

PARTIAL geom.grid cases=621 passed=619 failed=0 deferred=2 max_rel_err=0e0 with_values=619 no_values=0 vacuous=0 blocked_by=surface.surface_cache_p1(1),surface.surface_p2(1)
difftest: 260 unit(s), 189 passed, 71 partial, 0 failed

All six new cases pass substantive native comparisons; the original 613 passes and original two deferrals remain. Canonical runner tests passed all six new tests, including stable-owner separation, actual cache-node rejection, the original deferrals, corpus preservation, and mutation detection for skipped expansion/wrong identity/corrupted normal. Runner-test summary: 264 passed, 0 failed, 32 ignored (none of this change’s tests ignored).

Validation / review boundary

Passed locally: explicit-path rustfmt check, staged diff check, JSON/schema and seven-path scope checks, byte-preservation checks. Per authorization, no local Cargo/native builds, native tests, C++ fetching, dependency work, or full-suite run occurred. Native parity and mutation-sensitivity tests passed in the exact-head canonical run above.

Independent review found no blocking findings within the explicit bounded affine input family and verified all seven exact-head CI jobs. Approved for PR ready status only. geom.grid remains partial: these are six NEW affine cases, not recovery of the original two deferrals. No general curved-cache coverage is claimed. No code, commit, push, unit-status, merge, queue or cleanup action accompanies this readiness change; the lane, branch and evidence are retained.

Co-Authored-By: GPT-6.1 Sol Fast noreply@openai.com