{
  "schema": 1,
  "captured_on": "2026-07-31",
  "checkpoint": "curve-region2-mutation-outcomes",
  "source_revision": "cc6afbdf55adeedb62afd0d6253f173322583092",
  "parent_revision": "831a21ca510b520d2673179fcdd6778f27d11091",
  "implementation_revisions": [
    "cc6afbdf55adeedb62afd0d6253f173322583092"
  ],
  "frozen_baseline_revision": "dfc4ec5f9546560765bd33d4a88292581869adb8",
  "baseline": "../baselines/2026-07-31/baseline.json",
  "semantic_evidence": {
    "policy_explicit_public_mutation_apis": [
      "CurveRegion2::transform_affine",
      "CurveRegion2::transform_similarity",
      "CurveRegion2::chamfer_loop_vertex_by_parameters",
      "CurveRegion2::fillet_loop_vertex_by_parameters",
      "CurveRegion2::segment_certified",
      "CurveRegion2::offset_with_certified_segmentation",
      "CurveRegion2::offset_with_certified_bezier_parallel"
    ],
    "mutation_return_contract": "CurveOutcome<T>",
    "internal_composition_uses_raw_mutation_kernels": true,
    "mutation_geometry_is_evaluated_once": true,
    "operation_certainty_is_aggregated_once": true,
    "strict_symbolic_fillet_result": "Certified outcome containing Classification::Uncertain(RealSign)",
    "approximate_512_symbolic_fillet_result": "exact native line/arc CurveRegion2",
    "strict_symbolic_segmentation_result": "Certified outcome containing Classification::Uncertain(Ordering)",
    "approximate_512_symbolic_segmentation_result": "exact-Real chord region with Approximate512Consumed",
    "strict_symbolic_collapse_offset_result": "Certified outcome containing uncertainty",
    "approximate_512_symbolic_collapse_offset_result": "decided exact empty region with Approximate512Consumed",
    "returned_geometry_remains_exact": true,
    "compatibility_overload_or_implicit_value_shim_added": false
  },
  "closed_failure_paths": {
    "symbolic_center_arc_area": {
      "previous_behavior": "infallible Real::atan2 panicked while rebuilding native fillet topology",
      "current_behavior": "center_arc_signed_sweep uses try_atan2 and reports unavailable legacy contour area without panicking",
      "authoritative_fix": "native_region_from_curve_paths no longer computes legacy contour signed areas merely to seed filled-side evidence"
    },
    "exact_orthogonal_erosion_collapse": {
      "previous_behavior": "degenerate joined offset linework raised Real(UnknownZero) before the exact erosion lane ran",
      "current_behavior": "contracting all-line components schedule exact orthogonal erosion before raw joined-offset construction",
      "approximate_512_terminal": "the symbolic collapse decision completes once and reports Approximate512Consumed"
    }
  },
  "verification": {
    "cargo_test_all_features": "pass",
    "unit_tests": 254,
    "exact_curve_region2_fuzz_seconds": 160.91,
    "pathological_operations": "268/268 decided with no blockers",
    "cargo_check_all_features_all_targets": "pass",
    "cargo_clippy_all_features_all_targets_deny_warnings": "pass",
    "cargo_check_no_default_features_all_targets": "pass",
    "cargo_clippy_no_default_features_all_targets_deny_warnings": "pass",
    "cargo_check_fuzz_all_targets": "pass",
    "cargo_doc_all_features_deny_warnings": "pass",
    "cargo_fmt_all": "pass",
    "git_diff_check": "pass",
    "csgrs_commit": "f47a28e",
    "csgrs_all_feature_check_clippy_and_tests": "pass",
    "csgrs_fuzz_all_targets": "pass",
    "csgrs_no_default_all_targets": "pre-existing ungated example/test failures, unrelated to this migration",
    "hyperdrc_commit": "6c6d776",
    "hyperdrc_all_feature_check_clippy_and_tests": "pass, including 1114 unit tests",
    "hyperdrc_no_default_all_targets": "pass"
  },
  "matched_mutation_benchmarks": {
    "command": "seven interleaved parent/candidate executions of the release editing benchmark at 10000 iterations, reversing execution order on alternate pairs",
    "benchmark_harness": "persistent CurveRegion2 affine-transform, parameter-chamfer, and parameter-fillet rows added to benches/editing.rs",
    "parent_revision": "831a21ca510b520d2673179fcdd6778f27d11091",
    "candidate_revision": "cc6afbdf55adeedb62afd0d6253f173322583092",
    "curve_region_affine_transform_ns": {
      "parent_samples": [
        4700.9827,
        4361.9100,
        4511.4707,
        4513.6736,
        4385.2293,
        4327.1553,
        4418.7051
      ],
      "candidate_samples": [
        4368.1605,
        4542.6095,
        4294.6426,
        4352.1046,
        4536.2920,
        4420.3129,
        4487.0204
      ],
      "parent_median": 4418.7051,
      "candidate_median": 4420.3129,
      "change_percent": 0.0364
    },
    "curve_region_parameter_chamfer_ns": {
      "parent_samples": [
        10603.5261,
        10123.6370,
        10398.6041,
        10295.1852,
        10290.2205,
        10277.4884,
        10375.0777
      ],
      "candidate_samples": [
        9638.1583,
        10223.1801,
        9539.3651,
        9735.1376,
        9695.4813,
        9598.8739,
        9843.0962
      ],
      "parent_median": 10295.1852,
      "candidate_median": 9695.4813,
      "change_percent": -5.8251
    },
    "curve_region_parameter_fillet_ns": {
      "parent_samples": [
        19755.0917,
        18406.1442,
        19110.1989,
        19055.5536,
        18519.1514,
        18732.6187,
        19365.1593
      ],
      "candidate_samples": [
        12114.8115,
        12088.3953,
        12063.0320,
        11920.1498,
        12189.5103,
        11983.2055,
        12136.3600
      ],
      "parent_median": 19055.5536,
      "candidate_median": 12088.3953,
      "change_percent": -36.5624
    },
    "interpretation": "explicit outcome aggregation is neutral for affine transforms; avoiding eager legacy area work improves chamfer and removes more than one third of native fillet runtime"
  },
  "pathological_curve_region2": {
    "command": "seven independent executions of target/release/deps/pathological_regions-524727024aa54dcb --bench",
    "cells": 67,
    "operations": 268,
    "completed_operations": 268,
    "blockers": 0,
    "checksum": 6,
    "candidate_pairs": 603,
    "retained_fragments": 3248,
    "point_classifications": 134,
    "candidate_all_four_native_booleans_ms": [
      469.122179,
      468.048962,
      462.843259,
      464.033737,
      460.472661,
      463.098041,
      466.888112
    ],
    "candidate_median_ms": 464.033737,
    "preceding_checkpoint_median_ms": 472.054000,
    "frozen_baseline_median_ms": 471.450000,
    "change_from_preceding_checkpoint_percent": -1.6990,
    "change_from_frozen_baseline_percent": -1.5731,
    "candidate_build_ms": [
      76.164458,
      73.461513,
      75.949593,
      73.758103,
      71.574403,
      70.331578,
      72.780700
    ],
    "candidate_build_median_ms": 73.461513,
    "preceding_checkpoint_build_median_ms": 72.842566,
    "build_change_percent": 0.8497,
    "candidate_observed_rss_delta_mib": [
      34.7,
      34.8,
      34.7,
      34.8,
      34.7,
      34.8,
      34.7
    ],
    "candidate_observed_rss_delta_mib_median": 34.7,
    "interpretation": "deterministic topology is identical; Boolean execution improved 1.7 percent, construction remained within one percent, and process-scale RSS is unchanged"
  },
  "comparative_release_medians_ns": {
    "command": "HYPERCURVE_COMPARE_SAMPLES=7 HYPERCURVE_COMPARE_SAMPLE_MS=75 cargo bench --locked --features comparative-benchmarks --bench comparative",
    "candidate_revision": "cc6afbdf55adeedb62afd0d6253f173322583092",
    "rectangle_union": {
      "hypercurve": 4856.4,
      "hypercurve_contours": 4649.1,
      "hypercurve_loops": 5178.8,
      "cavalier_contours": 870.1,
      "i_overlay": 1024.3,
      "geo": 1213.5,
      "change_from_preceding_checkpoint_percent": 2.9968
    },
    "star64_intersection": {
      "hypercurve": 35809.3,
      "hypercurve_contours": 35081.8,
      "hypercurve_loops": 99220.4,
      "cavalier_contours": 27330.8,
      "i_overlay": 33983.1,
      "geo": 35836.2,
      "change_from_preceding_checkpoint_percent": 0.9079
    },
    "star256_intersection": {
      "hypercurve": 419755.1,
      "hypercurve_contours": 293638.8,
      "hypercurve_loops": 844707.2,
      "cavalier_contours": 483986.4,
      "i_overlay": 504702.8,
      "geo": 512626.7,
      "change_from_preceding_checkpoint_percent": 0.4903
    },
    "star1024_intersection": {
      "hypercurve": 5057771.9,
      "hypercurve_contours": 3875207.4,
      "hypercurve_loops": 10929043.6,
      "cavalier_contours": 19251492.5,
      "i_overlay": 10004594.1,
      "geo": 10409897.6,
      "change_from_preceding_checkpoint_percent": 0.9375
    },
    "inward_capsule_offset": {
      "broad_run_hypercurve": 19750.6,
      "broad_run_cavalier_contours": 924.7,
      "broad_run_change_from_preceding_checkpoint_percent": 4.1869,
      "tight_parent_medians": [
        19193.7,
        19253.9,
        19114.7
      ],
      "tight_candidate_medians": [
        19056.7,
        18635.0,
        18609.9
      ],
      "tight_parent_median": 19193.7,
      "tight_candidate_median": 18635.0,
      "tight_change_percent": -2.9109,
      "tight_command": "three interleaved parent/candidate runs, each with 11 samples at 100 ms, group-filtered to line_arc_offset"
    },
    "certified_open_cubic_offset": {
      "hypercurve": 29351358.0,
      "curvo_heuristic": 8553.5,
      "change_from_preceding_checkpoint_percent": -1.7232
    },
    "source_chord_cubic_fallback": {
      "hypercurve": 904832.8,
      "change_from_preceding_checkpoint_percent": -1.7279
    },
    "rational_cubic_nurbs_evaluation": {
      "hypercurve": 1526.5,
      "curvo": 58.0,
      "change_from_preceding_checkpoint_percent": -6.2231
    },
    "interpretation": "Boolean lanes are within three percent of the preceding checkpoint; both Bezier offset rows and NURBS evaluation improved; a tighter matched control rejects the broad-run capsule regression and measures a 2.9 percent improvement"
  },
  "release_pathological_binary": {
    "measurement": "copy of the release executable stripped with strip --strip-all",
    "preceding_checkpoint_bytes": 5521424,
    "candidate_bytes": 5512272,
    "delta_bytes": -9152,
    "delta_percent": -0.1658,
    "frozen_baseline_bytes": 5531293,
    "delta_from_frozen_baseline_bytes": -19021,
    "delta_from_frozen_baseline_percent": -0.3439,
    "candidate_text_bytes": 5241481,
    "candidate_data_bytes": 266912,
    "candidate_bss_bytes": 2464
  },
  "static_callgraph": {
    "command": "hyper-callgraph --root . --crate-name hypercurve --include-examples --include-tests --include-bench --include-fuzz --format json",
    "nodes": 22341,
    "edges": 38191,
    "artifact": "/tmp/hypercurve-mutation-callgraph/callgraph.json",
    "public_and_raw_mutation_nodes_present": true,
    "persistent_curve_region_mutation_benchmark_nodes_present": true
  }
}