Adjust BoundedGeoHexGridTiler#FACTOR to prevent missing hits (#96088)

Adjust the percentage we are using to inflate the bounding box on the bounded case of geohex to fix a test failure.

Author: iverase

docs/changelog/96088.yaml

@@ -0,0 +1,6 @@
+pr: 96088
+summary: Adjust `BoundedGeoHexGridTiler#FACTOR` to prevent missing hits
+area: Geo
+type: bug
+issues:
+ - 96057

x-pack/plugin/spatial/src/main/java/org/elasticsearch/xpack/spatial/search/aggregations/bucket/geogrid/GeoHexGridTiler.java

@@ -240,7 +240,7 @@ static class BoundedGeoHexGridTiler extends GeoHexGridTiler {
         private final GeoBoundingBox bbox;
         private final GeoHexVisitor visitor;
         private final int resolution;
-        private static final double FACTOR = 0.35;
+        private static final double FACTOR = 0.36;
 
         BoundedGeoHexGridTiler(int resolution, GeoBoundingBox bbox) {
             super(resolution);

x-pack/plugin/spatial/src/test/java/org/elasticsearch/xpack/spatial/search/aggregations/bucket/geogrid/GeoHexTilerTests.java

@@ -13,7 +13,9 @@
 import org.elasticsearch.common.geo.GeoPoint;
 import org.elasticsearch.geo.GeometryTestUtils;
 import org.elasticsearch.geometry.Geometry;
+import org.elasticsearch.geometry.LinearRing;
 import org.elasticsearch.geometry.Point;
+import org.elasticsearch.geometry.Polygon;
 import org.elasticsearch.geometry.Rectangle;
 import org.elasticsearch.geometry.utils.StandardValidator;
 import org.elasticsearch.geometry.utils.WellKnownText;
@@ -230,6 +232,31 @@ public void testTroublesomeCellLevel4_BoundedGeoShapeCellValues() throws Excepti
         assertThat("[" + precision + "] bucket count", numBuckets, equalTo(expected));
     }
 
+    public void testIssue96057() throws Exception {
+        int precision = 3;
+        Geometry geometry = new Polygon(
+            new LinearRing(
+                new double[] { 47.0, 47.0, -98.41711495022405, -98.41711495022405, 47.0 },
+                new double[] { -43.27504297314639, 23.280704041384652, 23.280704041384652, -43.27504297314639, -43.27504297314639 }
+            )
+        );
+        GeoBoundingBox geoBoundingBox = new GeoBoundingBox(
+            new GeoPoint(-44.363846082646845, 55.61563600452277),
+            new GeoPoint(-75.8747796394427, 42.12290817616412)
+        );
+        GeoShapeValues.GeoShapeValue value = geoShapeValue(geometry);
+        GeoShapeCellValues cellValues = new GeoShapeCellValues(
+            makeGeoShapeValues(value),
+            getGridTiler(geoBoundingBox, precision),
+            NOOP_BREAKER
+        );
+
+        assertTrue(cellValues.advanceExact(0));
+        int numBuckets = cellValues.docValueCount();
+        int expected = expectedBuckets(value, precision, geoBoundingBox);
+        assertThat(numBuckets, equalTo(expected));
+    }
+
     private void assertCorner(long[] h3bins, Point point, int precision, String msg) throws IOException {
         GeoShapeValues.GeoShapeValue cornerValue = geoShapeValue(point);
         GeoShapeCellValues cornerValues = new GeoShapeCellValues(makeGeoShapeValues(cornerValue), getGridTiler(precision), NOOP_BREAKER);