P2.4 two-hole arrangement (OV-P2 / Bar 2)

[grootstebozewolf]

Stacked on cursor/p23-bite-vs-hole-3909 @ 7a3a4fb (draft #18). Do not merge this into #7. This is OV-P2 / Bar 2, not OV-P1. Does not merge #12 / #13 / #15 / #16 / #17 / #18 / #7. Does not push to feature/sfa-curve-rgr or master.

Sentence

The noder is the named-miss suite, one assembly rule at a time. Nodes (P2.1), overlap-as-edge (P2.2), bite vs hole (P2.3), then two-hole arrangement. Densify is never a noder. Snap-rounding is not this rung.

What this is

P2.4 is the next face walk after P2.3, and only this cell:

H-SHELL-HOLE-X — two holes that cross.

Same HALF_DISC outer. Two axis-aligned unit squares:

• holeA (0 1, 1 1, 1 2, 0 2, 0 1)
• holeB (0.5 0.5, 1.5 0.5, 1.5 1.5, 0.5 1.5, 0.5 0.5)

They overlap in [0.5,1] × [1,1.5]. The Geometry-level noder still returns null (the pair has holes). The hole rings are LineStrings: P2.1 names the two crossing nodes (0.5 1) and (1 1.5). No shared run (P2.2 edges empty). No circular–circular hole hits. Snap-rounding was not required.

Face assembly is a 3-ring arrangement (shared circular shell + two hole rings). Package-private TwoHoleOverlay walks each hole in and out of the other with CurveSegmentString / CurveSegmentNoder / TwoNodeClip, then:

• CAP = HALF_DISC \ (holeA ∪ holeB) — area 12.5π − 1.75
• CUP = HALF_DISC \ (holeA ∩ holeB) — area 12.5π − 0.25
• SUB A\B = holeB \ holeA — area 0.75
• XOR = holeA △ holeB — area 1.5

Exact, isApproximate()=false. Decide / clip-node pins sit next to the overlay pin. No new public API. No noder in jts-core. Name is OverlayNGCurve. P2.5 / N-SS was not started.

Lasering vs stamped

Fixture	This rung
H-SHELL-HOLE-X	Laser. Two-node hole–hole walk. CAP/CUP/SUB/XOR exact.
H-SHELL-HOLE-CROSS	Unchanged bite.
H-SHELL-HOLE-OUTER (hole meets the other diameter)	Named miss. Collinear, stays assertNull.
SAME-OUTER / DIFF-OUTER	Unchanged.
P2.1 node pins / P2.2 MIXED / H-SAME-CIRCLE / H-ANNULUS-TANGENT / TOUCH-ext	Unchanged.
4-node / collinear hole overlap / snap-rounding	Would stamp assertNull. This fixture did not need them.

What this is not

• Not P2.5 / N-SS (no public SegmentString / Noder in jts-core)
• Not a snap-rounding noder
• Not densify-then-node flagged as exact
• Not a merge into feature/sfa-curve-rgr / PR SFA/SQL-MM curve awareness: Curve rename, arc-aware operations, OverlayNGCurve ratchet (#1195 RGR series) #7 / locationtech master
• Not a general arrangement engine
• Not H-SHELL-HOLE-OUTER / H-SHELL-HOLE-CROSS / MIXED / H-SAME-CIRCLE / H-ANNULUS-TANGENT / TOUCH-ext / R1.6-honesty / CC-NEST-ANNULUS

Verify

mvn -pl modules/curve -am test -DfailIfNoTests=false -Dcheckstyle.skip=true -Dpmd.skip=true \
  -Dtest=CurveSegmentStringTest,CompoundCurveShellOverlayTest,CircularArcOverlayTest,CircularDiscOverlayTest,CircularDiscPolygonOverlayTest,CircularLineOverlayTest,OverlayNGCurvePhase0Test,OverlayNGCurveRatchetTest,OverlayNGCurvePerfGateTest
bash dev/check-no-curved.sh
mvn -pl modules/curve checkstyle:check
mvn -pl modules/curve pmd:check

All green after this revision:

• CurveSegmentStringTest 16 / 0 (hole-ring nodes (0.5 1) / (1 1.5); Geometry-level pair still null; BiteVsHole.MISS; TwoHoleOverlay.CROSS)
• CompoundCurveShellOverlayTest 26 / 0 (HOLE-X CAP/CUP/SUB/XOR exact; HOLE-CROSS / SAME-OUTER / DIFF-OUTER / HOLE-OUTER / MIXED unchanged)
• CircularArcOverlayTest 11 / 0
• CircularDiscOverlayTest 12 / 0
• CircularDiscPolygonOverlayTest 7 / 0
• CircularLineOverlayTest 7 / 0
• OverlayNGCurvePhase0Test 19 / 0
• OverlayNGCurveRatchetTest 48 / 0 (two-hole cross EEEE both orders)
• OverlayNGCurvePerfGateTest 82 / 0 (15% slack)
• Naming-guard OK; Checkstyle 0 violations; PMD check on jts-curve succeeded

Slack stays 15%. Overlay name is OverlayNGCurve. No new public API. No noder was written in jts-core. P2.5 / N-SS was not started.