v0.3.120

v0.3.120 — gam 0.3.120 / gamfit 0.1.222 (2026-06-21)

crates.io + PyPI release of the open-issue bug-fix wave landed since gamfit
0.1.221 (gam 0.3.119), plus the #1452/#1288 releasability cleanup that re-arms the
build.rs hygiene gate to a hard failure and brings the tree into compliance so a
release can actually build the gamfit wheel.

Releasability / hygiene (#1452 / #1288 / #780 / #871)

• The build.rs ban-scanner is back to a hard exit(1): no #[ignore] tests,
  no debug_assert!, no unreachable!, no manifest dead_code = "allow", no
  underscore-prefixed unused parameters, no #[cfg(test)] items outside a test
  module, and no tracked file over 10k lines. The whole tree now complies and
  builds clean under [lints.rust] warnings = "deny".
• Finished the #1288 dead-code cleanup: removed the never-consumed third-order
  d3qdot location-scale qdot jet and the unwired batched
  jeffreys_*_flex_no_wiggle / basis-contraction survival fast paths, scoped the
  #932 jet-scalar oracle structs to their test module, and dropped leftover
  #932 directional FD-localizer debug scaffolding.
• Promoted cheap invariant debug_assert!/debug_assert_eq! to always-on
  assert!/assert_eq! (penalty-root rank consistency, Duchon hybrid-integral
  precondition); dropped release-noop debug assertions where the documented
  contract wants honest IEEE NaN/inf propagation; replaced a banned
  unreachable! with a // SAFETY:-justified panic!.

Inference & numerics

• #1436: a typed OuterGradientError (IllConditioned / NonIdentifiable /
  InternalInvariant) narrows the SAE FD-fallback so only genuine
  conditioning/identifiability failures admit the finite-difference descent
  direction at a finite-cost ρ, while internal-invariant defects propagate as
  hard errors. NonIdentifiable is now constructed at the gauge-degenerate,
  non-deflatable outer-gradient site.
• #1424 / #1422 / #1423: cancellation-free hybrid Duchon-Matern kernel
  evaluation and a PSD mixed-periodicity Duchon penalty via an additive tensor
  reproducing kernel, with the correct cylinder nullspace.
• #1271 / #1266 / #1380 / #1089: the REML log-λ cap is lifted off
  well-determined Gaussian-identity smooths so REML can reach the null-space
  optimum, without changing the global default.
• #1391 / #1397 / #1017: post-T rank invariant is anchored to the audit's
  kept-rank certificate and made robust to the drop-deciding convention;
  relaxed over-strict arrow-Schur parity asserts to a tight relative tolerance.
• #1376 / #1398 / #1404: anisotropic Matern ψ-derivative centered to the
  raw-η gauge; isotropic sphere-harmonic penalty and closed-form Sobolev jet
  with a constant-curvature effective-length contract.
• #1426: a stuck gamma/log REML stall is no longer shipped as a flat valley.
• #1385: competing-risks CIF assembled on a refined internal grid.

Survival (#932 / #979 / #1394 / #1396)

• Moving-boundary flux / implicit-function / substitution jet-tower combinators
  for the θ-dependent flex-calibration integrand, carried exactly to fourth
  order, with the survival location-scale time-channel NLL sign living in a
  single source of truth and rigid-kernel non-finite margin propagation.

Smooths, factors & summaries

• #1403: s(x, by=factor) routes to BySmooth::Factor, s(x, by=numeric)
  to BySmooth::Numeric, and bs="sz" factor smooths to FactorSmooth { Sz }.
• #1378: default univariate thin-plate basis sized to mgcv k=10, with
  row-permutation-invariant knot selection.
• #1364: P-spline scale equivariance.
• #1384: compare_models refuses to rank fits of different response families.
• #1370 / #1368 / #1369: summary() synthesizes valid factor levels for the
  smooth-term replay so fs/sz/by smooths keep their EDF and per-level
  labels.

Manifold-SAE

• #1405 / #1406 / #1410 / #1411 / #1412: matrix-free planner predicts the
  true cross footprint; compact support is partial-selected and per-worker
  scratch sized by compact dims; encode bench gates honest support recovery.
• #1026: collinearity-gated decoder repulsion conditions the SAE
  co-collapse direction with a keep-best multi-start.

Error messages

• #1445: NaN/None/empty table-cell errors now name the offending column and
  row instead of an unactionable bare message.

See the git history (git log v0.3.118..v0.3.120) for the complete set.