[altvnk]

Scoped completion claim

Units: curve.curve_p4.

In scope: genuine noncircle Ellipse as an ordinary curve input, plus one named
SmCPDistAtENFO::Evaluate regression comparing all equations and Jacobian entries.
Existing ellipse analytic operands do not reach this ordinary-curve evaluator;
existing circle shorthand constructs a B-spline and will remain unchanged.

Expected edits:

• crates/difftest/src/units/curve_curve_p4.rs
• crates/solidcore-ffi/src/units/curve_curve_p4.rs
• harness/cpp/shim/curve_curve_p4.cpp
• fixtures/curve.curve_p4/analytic-distance.json

Evidence: fresh inspected main b206d3f5a38127dc3a0b6c511f1b45116826b341
admits only ordinary B-spline/Hermite/Line protocol kinds. Reuse the existing real
ellipse constructor and validation in this unit's dedicated analytic path, adding
ordinary kind 3 without reinterpreting kinds 0–2 or restricting the new kind to one
operation. Its ordinary block places dimension before geometry; the old analytic
operand layout and read order stay unchanged. No production interface is needed.

One bounded, noncanonical Rust-only probe used radii (2,1), angular extent
[0,180], actual NURB interval [0,1], point (0.25,-0.5,0.25), dsq=1,
sqtol=0, variables [0.5,0.1,0.2,0.3] and Jacobian enabled. Four finite equations
and all 16 Jacobian entries matched source controls; geometric J[0,0] was
approximately 2.8284271247461885. This evaluates equations, not a solved distance
or root. No native or fresh-head success is claimed by that probe.

Validation planned: actual fixture discovery/encoding and real-kind/domain tests;
source-derived equation and Jacobian controls; new-kind generic admission and old
guard/error-order preservation; modified-shim compilation and complete native
records; a targeted nonzero geometric-Jacobian perturbation; complete unfiltered
affected unit and perturbation; formatting and CPP-enabled Clippy; independent
final-diff review; all canonical exact-head native/value-share/exact-base gates.
Reuse shared reference libraries read-only. A native mismatch or extra production
need blocks this scope, rather than causing an input, guard or tolerance change.

Preserve every old fixture, generated input, RNG draw/seed/minimum, kind layout,
validation predicate, output entry, mismatch, numerical formula, tolerance and
status. No production, cache, shared-interface, plan, workflow or old-fixture edits.

Related PRs / dependencies: #686 ellipse STEP mutation, #1031/#1042 cache/interfaces,
#1041 p9 diagonal coverage and #1047 p6 Sphere coverage remain separate and untouched.
Available follow-ups: other concrete-kind/operation success paths are unclaimed;
generic admission does not establish their coverage.

Status / blockers / next step: scoped draft; implement the reviewed four-path
protocol and fixture, establish native equivalence, then await canonical CI.
Maintainers retain workflow authorization, approval, queue admission and merging.

Published draft: exact-head evidence

Head 31fc16fe56ffe6751c0ba8b47890da69d4e4b19b, safely synchronized with authoritative main f4d002bb0a6dc5d49928a80213eb9ade8cdab7bd.
Independent final source review accepted fingerprint 7f41403ebbe5b2ebbecdd2c014bccdcd3b31db7b22812494600daed1a145571b.
Reviewed binary PR diff unchanged across safe merge; all old fixtures/generator
inputs/kind layouts/guards/numerical formulas and tolerances are preserved.

2 focused CPP runner tests and3FFI admission tests passed
PASS curve.curve_p4 cases=3260 passed=3260 failed=0 deferred=0 max_rel_err=0e0 with_values=3260 no_values=0 vacuous=0
SENSITIVE curve.curve_p4 perturbed=3260 detected=3260 unperturbed=0 deferred=0
CPP-enabled Clippy both changed Rust crates all-targets -D warnings: PASS
workspace formatting and diff checks: PASS

Operation / symbols	Implementation	Successful native comparison	Remaining gap
SmCPDistAtENFO::Evaluate; ellipse_cp_dist_at_interior_full_jacobian	Generic genuine noncircle Ellipse ordinary curve kind3; existing equations unchanged	Full4equations+16Jacobian entries+found flag and status compare; J00~2.8284271247461885; targeted nonzero geometric Jacobian perturbation rejected	Equation evaluation only, not a solved distance/root; other admitted operations not newly demonstrated

Source-preserving identical Hermite/Ellipse range arms were consolidated to satisfy
Clippy. This changes neither old decisions nor generator selection. Shared native
reference hashes/mtimes unchanged, no rebuild. Local macOS evidence is not canonical
Linux or implementation-completeness proof. Ready for review by explicit user instruction; canonical CI is still pending.

User-authorized review status

Marked ready for review at the user’s request after local native validation and independent source review. Canonical CI was authorization-blocked at the latest audit; this transition does not claim green CI, approval, queue admission or merge readiness. Maintainer workflow authorization and all required checks remain mandatory. No source commit or workflow configuration changed.

[altvnk]

@bherbruck — exact published draft head 31fc16fe5 passed independent final source review, local2CPP+3FFI tests, full native curve.curve_p4 3260/3260 cases, perturbation3260/3260, CPP-enabled Clippy and formatting. The new genuine Ellipse fixture compares all4equations/16Jacobian entries/found flag and status; old fixtures, generator inputs, guards and tolerances are unchanged. Canonical run40248674299 requires authorization and has executed zero jobs. Please inspect/authorize it; draft remains pending all13canonical jobs/native/value-share/exact-base retention. Equation evaluation is not a solved-distance claim; no technical CI failure or merge-readiness claim.

[bherbruck]

Approved by the automated first-pass review: CI green, mergeable, no CI/build/dependency file changes, no red-flag patterns in added code (process/network/env/unsafe outside FFI/blobs/hidden unicode), 0 known-mismatch entries added. Logic is gated by CI and the difftest merge queue.