From 4ab711166886c0ec3b14909feb06123247fdfa04 Mon Sep 17 00:00:00 2001
From: Igor Motov <igor@motovs.org>
Date: Wed, 11 Sep 2019 14:53:10 -0400
Subject: [PATCH] Geo: fix indexing of west to east linestrings crossing the
 antimeridian (#46601)

Fixes that way linestrings that are crossing the antimeridian are
indexed due to a normalization bug these lines were decomposed into
a line segment that was stretching entire globe.

Fixes #43775
---
 .../index/mapper/GeoShapeIndexer.java         | 13 +++++++---
 .../common/geo/GeometryIndexerTests.java      | 24 ++++++++++++++++---
 2 files changed, 31 insertions(+), 6 deletions(-)

diff --git a/server/src/main/java/org/elasticsearch/index/mapper/GeoShapeIndexer.java b/server/src/main/java/org/elasticsearch/index/mapper/GeoShapeIndexer.java
index e3de485fc7a32..54fb9a97a8658 100644
--- a/server/src/main/java/org/elasticsearch/index/mapper/GeoShapeIndexer.java
+++ b/server/src/main/java/org/elasticsearch/index/mapper/GeoShapeIndexer.java
@@ -229,7 +229,7 @@ private List<Line> decomposeGeometry(Line line, List<Line> lines) {
                 double[] lons = new double[partMinus.length()];
                 for (int i = 0; i < partMinus.length(); i++) {
                     lats[i] = normalizeLat(partMinus.getY(i));
-                    lons[i] = normalizeLon(partMinus.getX(i));
+                    lons[i] = normalizeLonMinus180Inclusive(partMinus.getX(i));
                 }
                 lines.add(new Line(lons, lats));
             }
@@ -274,7 +274,7 @@ private List<Line> decompose(double dateline, double[] lons, double[] lats) {
                     lons[offset + i - 1] = intersection.getX();
                     lats[offset + i - 1] = intersection.getY();
 
-                    shift(shift, lons);
+                    shift(shift, partLons);
                     offset = i - 1;
                     shift = lons[i] > DATELINE ? DATELINE : (lons[i] < -DATELINE ? -DATELINE : 0);
                 } else {
@@ -926,7 +926,7 @@ private static Polygon buildPolygon(List<Point[]> polygon) {
         for (int i = 0; i < shell.length; ++i) {
             //Lucene Tessellator treats different +180 and -180 and we should keep the sign.
             //normalizeLon method excludes -180.
-            x[i] = Math.abs(shell[i].getX()) > 180 ? normalizeLon(shell[i].getX()) : shell[i].getX();
+            x[i] = normalizeLonMinus180Inclusive(shell[i].getX());
             y[i] = normalizeLat(shell[i].getY());
         }
 
@@ -1043,4 +1043,11 @@ public static org.apache.lucene.geo.Polygon toLucenePolygon(Polygon polygon) {
         }
         return new org.apache.lucene.geo.Polygon(polygon.getPolygon().getY(), polygon.getPolygon().getX(), holes);
     }
+
+    /**
+     * Normalizes longitude while accepting -180 degrees as a valid value
+     */
+    private static double normalizeLonMinus180Inclusive(double lon) {
+        return  Math.abs(lon) > 180 ? normalizeLon(lon) : lon;
+    }
 }
diff --git a/server/src/test/java/org/elasticsearch/common/geo/GeometryIndexerTests.java b/server/src/test/java/org/elasticsearch/common/geo/GeometryIndexerTests.java
index 5e5b2b688ea17..47b02ea698112 100644
--- a/server/src/test/java/org/elasticsearch/common/geo/GeometryIndexerTests.java
+++ b/server/src/test/java/org/elasticsearch/common/geo/GeometryIndexerTests.java
@@ -72,7 +72,7 @@ public void testCollection() {
             new Point(2, 1), new Point(4, 3),
             new MultiLine(Arrays.asList(
                 new Line(new double[]{160, 180}, new double[]{10, 15}),
-                new Line(new double[]{180, -160}, new double[]{15, 20}))
+                new Line(new double[]{-180, -160}, new double[]{15, 20}))
             ))
         );
         assertEquals(indexed, indexer.prepareForIndexing(collection));
@@ -87,7 +87,25 @@ public void testLine() {
         line = new Line(new double[]{160, 200}, new double[]{10, 20});
         indexed = new MultiLine(Arrays.asList(
             new Line(new double[]{160, 180}, new double[]{10, 15}),
-            new Line(new double[]{180, -160}, new double[]{15, 20}))
+            new Line(new double[]{-180, -160}, new double[]{15, 20}))
+        );
+
+        assertEquals(indexed, indexer.prepareForIndexing(line));
+
+        line = new Line(new double[]{200, 160}, new double[]{10, 20});
+        indexed = new MultiLine(Arrays.asList(
+            new Line(new double[]{-160, -180}, new double[]{10, 15}),
+            new Line(new double[]{180, 160}, new double[]{15, 20}))
+        );
+
+        assertEquals(indexed, indexer.prepareForIndexing(line));
+
+        line = new Line(new double[]{160, 200, 160}, new double[]{0, 10, 20});
+        indexed = new MultiLine(Arrays.asList(
+            new Line(new double[]{160, 180}, new double[]{0, 5}),
+            new Line(new double[]{-180, -160, -180}, new double[]{5, 10, 15}),
+            new Line(new double[]{180, 160}, new double[]{15, 20})
+            )
         );
 
         assertEquals(indexed, indexer.prepareForIndexing(line));
@@ -106,7 +124,7 @@ line, new Line(new double[]{160, 200}, new double[]{10, 20})
         indexed = new MultiLine(Arrays.asList(
             line,
             new Line(new double[]{160, 180}, new double[]{10, 15}),
-            new Line(new double[]{180, -160}, new double[]{15, 20}))
+            new Line(new double[]{-180, -160}, new double[]{15, 20}))
         );
 
         assertEquals(indexed, indexer.prepareForIndexing(multiLine));