Fix parsing of "geo_distance" filter wrt "distance" / "unit" parameters

The problem was that when "unit" was given,
the conversion to miles was happening too early,
which caused wrong computations. This change
postpones this computation when one really knows
which unit should be used.

Author: Adriano Ferreira

modules/elasticsearch/src/main/java/org/elasticsearch/index/query/xcontent/GeoDistanceFilterParser.java

@@ -74,7 +74,8 @@ public class GeoDistanceFilterParser extends AbstractIndexComponent implements X
         double lon = 0;
         String fieldName = null;
         double distance = 0;
-        DistanceUnit unit = null;
+        Object vDistance = null;
+        DistanceUnit unit = DistanceUnit.KILOMETERS; // default unit
         GeoDistance geoDistance = GeoDistance.ARC;
         while ((token = parser.nextToken()) != XContentParser.Token.END_OBJECT) {
             if (token == XContentParser.Token.FIELD_NAME) {
@@ -110,9 +111,9 @@ public class GeoDistanceFilterParser extends AbstractIndexComponent implements X
             } else if (token.isValue()) {
                 if (currentFieldName.equals("distance")) {
                     if (token == XContentParser.Token.VALUE_STRING) {
-                        distance = DistanceUnit.parse(parser.text(), DistanceUnit.KILOMETERS, DistanceUnit.MILES);
+                        vDistance = parser.text(); // a String
                     } else {
-                        distance = parser.doubleValue();
+                        vDistance = parser.numberValue(); // a Number
                     }
                 } else if (currentFieldName.equals("unit")) {
                     unit = DistanceUnit.fromString(parser.text());
@@ -150,8 +151,10 @@ public class GeoDistanceFilterParser extends AbstractIndexComponent implements X
             }
         }
 
-        if (unit != null) {
-            distance = unit.toMiles(distance);
+        if (vDistance instanceof Number) {
+            distance = unit.toMiles(((Number)vDistance).doubleValue());
+        } else {
+            distance = DistanceUnit.parse((String)vDistance, unit, DistanceUnit.MILES);
         }
 
         MapperService mapperService = parseContext.mapperService();