From cf568904005ca203076186820b9a7876f7cb1882 Mon Sep 17 00:00:00 2001
From: Ignacio Vera <ivera@apache.org>
Date: Wed, 4 Apr 2018 13:33:42 +0200
Subject: [PATCH] LUCENE-8236: Filter duplicated points when creating GeoPath
 shapes to avoid creation of bogus planes.

---
 lucene/CHANGES.txt                            |  3 +++
 .../lucene/spatial3d/geom/GeoPathFactory.java | 22 ++++++++++++++++--
 .../lucene/spatial3d/geom/GeoPathTest.java    | 23 +++++++++++++++++++
 3 files changed, 46 insertions(+), 2 deletions(-)

diff --git a/lucene/CHANGES.txt b/lucene/CHANGES.txt
index 1f839801433..95d8738cf8b 100644
--- a/lucene/CHANGES.txt
+++ b/lucene/CHANGES.txt
@@ -120,6 +120,9 @@ Bug Fixes
 * LUCENE-8234: Fixed bug in how spatial relationship is computed for
   GeoStandardCircle when it covers the whole world. (Ignacio Vera)
 
+* LUCENE-8236: Filter duplicated points when creating GeoPath shapes to
+  avoid creation of bogus planes. (Ignacio Vera)
+
 Other
 
 * LUCENE-8228: removed obsolete IndexDeletionPolicy clone() requirements from
diff --git a/lucene/spatial3d/src/java/org/apache/lucene/spatial3d/geom/GeoPathFactory.java b/lucene/spatial3d/src/java/org/apache/lucene/spatial3d/geom/GeoPathFactory.java
index 2ca132f1244..6389f57b70a 100644
--- a/lucene/spatial3d/src/java/org/apache/lucene/spatial3d/geom/GeoPathFactory.java
+++ b/lucene/spatial3d/src/java/org/apache/lucene/spatial3d/geom/GeoPathFactory.java
@@ -16,6 +16,9 @@
  */
 package org.apache.lucene.spatial3d.geom;
 
+import java.util.ArrayList;
+import java.util.List;
+
 /**
  * Class which constructs a GeoPath representing an arbitrary path.
  *
@@ -34,9 +37,24 @@ public class GeoPathFactory {
    */
   public static GeoPath makeGeoPath(final PlanetModel planetModel, final double maxCutoffAngle, final GeoPoint[] pathPoints) {
     if (maxCutoffAngle < Vector.MINIMUM_ANGULAR_RESOLUTION) {
-      return new GeoDegeneratePath(planetModel, pathPoints);
+      return new GeoDegeneratePath(planetModel, filterPoints(pathPoints));
     }
-    return new GeoStandardPath(planetModel, maxCutoffAngle, pathPoints);
+    return new GeoStandardPath(planetModel, maxCutoffAngle, filterPoints(pathPoints));
+  }
+
+  /** Filter duplicate points.
+   * @param pathPoints with the arras of points.
+   * @return the filtered array.
+   */
+  private static GeoPoint[] filterPoints(final GeoPoint[] pathPoints) {
+    final List<GeoPoint> noIdenticalPoints = new ArrayList<>(pathPoints.length);
+    for (int i = 0; i < pathPoints.length - 1; i++) {
+      if (!pathPoints[i].isNumericallyIdentical(pathPoints[i + 1])) {
+        noIdenticalPoints.add(pathPoints[i]);
+      }
+    }
+    noIdenticalPoints.add(pathPoints[pathPoints.length - 1]);
+    return noIdenticalPoints.toArray(new GeoPoint[noIdenticalPoints.size()]);
   }
 
 }
diff --git a/lucene/spatial3d/src/test/org/apache/lucene/spatial3d/geom/GeoPathTest.java b/lucene/spatial3d/src/test/org/apache/lucene/spatial3d/geom/GeoPathTest.java
index f6d14f2b6a0..93f90f4a67f 100755
--- a/lucene/spatial3d/src/test/org/apache/lucene/spatial3d/geom/GeoPathTest.java
+++ b/lucene/spatial3d/src/test/org/apache/lucene/spatial3d/geom/GeoPathTest.java
@@ -379,4 +379,27 @@ public class GeoPathTest {
 
   }
 
+  @Test
+  public void testIdenticalPoints() {
+    PlanetModel planetModel = PlanetModel.WGS84;
+    GeoPoint point1 = new GeoPoint(planetModel, 1.5707963267948963, -2.4818290647609542E-148);
+    GeoPoint point2 = new GeoPoint(planetModel, 1.570796326794895, -3.5E-323);
+    GeoPoint point3 = new GeoPoint(planetModel,4.4E-323, -3.1415926535897896);
+    GeoPath path = GeoPathFactory.makeGeoPath(planetModel, 0, new GeoPoint[] {point1, point2, point3});
+    GeoPoint point = new GeoPoint(planetModel, -1.5707963267948952,2.369064805649877E-284);
+    //If not filtered the point is wrongly in set
+    assertFalse(path.isWithin(point));
+    //If not filtered it throws error
+    path = GeoPathFactory.makeGeoPath(planetModel, 1e-6, new GeoPoint[] {point1, point2, point3});
+    assertFalse(path.isWithin(point));
+
+    GeoPoint point4 = new GeoPoint(planetModel, 1.5, 0);
+    GeoPoint point5 = new GeoPoint(planetModel, 1.5, 0);
+    GeoPoint point6 = new GeoPoint(planetModel,4.4E-323, -3.1415926535897896);
+    //If not filtered creates a degenerated Vector
+    path = GeoPathFactory.makeGeoPath(planetModel, 0, new GeoPoint[] {point4, point5, point6});
+    path = GeoPathFactory.makeGeoPath(planetModel, 0.5, new GeoPoint[] {point4, point5, point6});
+
+  }
+
 }