[GEO] GIS envelope validation

ShapeBuilder expected coordinates for Envelope types in strict Top-Left, Bottom-Right order. Given that GeoJSON does not enforce coordinate order (as seen in elastic#8672) clients could specify envelope bounds in any order and be compliant with the GeoJSON spec but not the ES ShapeBuilder logic. This change loosens the ShapeBuilder requirements on envelope coordinate order, reordering where necessary.

closes elastic#2544
closes elastic#9067
closes elastic#9079
closes elastic#9080

src/main/java/org/elasticsearch/common/geo/builders/ShapeBuilder.java

@@ -787,8 +787,20 @@ protected static CircleBuilder parseCircle(CoordinateNode coordinates, Distance
         }
 
         protected static EnvelopeBuilder parseEnvelope(CoordinateNode coordinates, Orientation orientation) {
-            return newEnvelope(orientation).
-                    topLeft(coordinates.children.get(0).coordinate).bottomRight(coordinates.children.get(1).coordinate);
+            // validate the coordinate array for envelope type
+            if (coordinates.children.size() != 2) {
+                throw new ElasticsearchParseException("Invalid number of points (" + coordinates.children.size() + ") provided for " +
+                        "geo_shape ('envelope') when expecting an array of 2 coordinates");
+            }
+            // verify coordinate bounds, correct if necessary
+            Coordinate uL = coordinates.children.get(0).coordinate;
+            Coordinate lR = coordinates.children.get(1).coordinate;
+            if (((lR.x < uL.x) || (uL.y < lR.y))) {
+                Coordinate uLtmp = uL;
+                uL = new Coordinate(Math.min(uL.x, lR.x), Math.max(uL.y, lR.y));
+                lR = new Coordinate(Math.max(uLtmp.x, lR.x), Math.min(uLtmp.y, lR.y));
+            }
+            return newEnvelope(orientation).topLeft(uL).bottomRight(lR);
         }
 
         protected static void validateMultiPointNode(CoordinateNode coordinates) {

src/test/java/org/elasticsearch/common/geo/GeoJSONShapeParserTests.java

@@ -121,6 +121,7 @@ public void testParse_circle() throws IOException {
 
     @Test
     public void testParse_envelope() throws IOException {
+        // test #1: envelope with expected coordinate order (TopLeft, BottomRight)
         String multilinesGeoJson = XContentFactory.jsonBuilder().startObject().field("type", "envelope")
                 .startArray("coordinates")
                 .startArray().value(-50).value(30).endArray()
@@ -130,6 +131,38 @@ public void testParse_envelope() throws IOException {
 
         Rectangle expected = SPATIAL_CONTEXT.makeRectangle(-50, 50, -30, 30);
         assertGeometryEquals(expected, multilinesGeoJson);
+
+        // test #2: envelope with agnostic coordinate order (TopRight, BottomLeft)
+        multilinesGeoJson = XContentFactory.jsonBuilder().startObject().field("type", "envelope")
+                .startArray("coordinates")
+                .startArray().value(50).value(30).endArray()
+                .startArray().value(-50).value(-30).endArray()
+                .endArray()
+                .endObject().string();
+
+        expected = SPATIAL_CONTEXT.makeRectangle(-50, 50, -30, 30);
+        assertGeometryEquals(expected, multilinesGeoJson);
+
+        // test #3: "envelope" (actually a triangle) with invalid number of coordinates (TopRight, BottomLeft, BottomRight)
+        multilinesGeoJson = XContentFactory.jsonBuilder().startObject().field("type", "envelope")
+                .startArray("coordinates")
+                .startArray().value(50).value(30).endArray()
+                .startArray().value(-50).value(-30).endArray()
+                .startArray().value(50).value(-39).endArray()
+                .endArray()
+                .endObject().string();
+        XContentParser parser = JsonXContent.jsonXContent.createParser(multilinesGeoJson);
+        parser.nextToken();
+        ElasticsearchGeoAssertions.assertValidException(parser, ElasticsearchParseException.class);
+
+        // test #4: "envelope" with empty coordinates
+        multilinesGeoJson = XContentFactory.jsonBuilder().startObject().field("type", "envelope")
+                .startArray("coordinates")
+                .endArray()
+                .endObject().string();
+        parser = JsonXContent.jsonXContent.createParser(multilinesGeoJson);
+        parser.nextToken();
+        ElasticsearchGeoAssertions.assertValidException(parser, ElasticsearchParseException.class);
     }
 
     @Test