From: Sandro Santilli <strk@keybit.net>
Date: Thu, 29 Nov 2012 17:49:27 +0000 (+0000)
Subject: Ensure ST_Centroid always returns POINT (#2109)
X-Git-Tag: 2.1.0beta2~350
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=460eab4e820ba363df33227eae19f45abaf1bf9a;p=postgis

Ensure ST_Centroid always returns POINT (#2109)

git-svn-id: http://svn.osgeo.org/postgis/trunk@10751 b70326c6-7e19-0410-871a-916f4a2858ee
---

diff --git a/postgis/lwgeom_geos.c b/postgis/lwgeom_geos.c
index cd31cf643..333fadaf1 100644
--- a/postgis/lwgeom_geos.c
+++ b/postgis/lwgeom_geos.c
@@ -1548,14 +1548,19 @@ Datum pointonsurface(PG_FUNCTION_ARGS)
 PG_FUNCTION_INFO_V1(centroid);
 Datum centroid(PG_FUNCTION_ARGS)
 {
+	LWGEOM *lwg;
 	GSERIALIZED *geom, *result;
 	GEOSGeometry *geosgeom, *geosresult;
 
 	geom = (GSERIALIZED *)  PG_DETOAST_DATUM(PG_GETARG_DATUM(0));
 
-	/* Empty.Centroid() == Empty */
+	/* Empty.Centroid() == Point Empty */
 	if ( gserialized_is_empty(geom) )
-		PG_RETURN_POINTER(geom);
+	{
+		lwg = lwpoint_construct_empty(gserialized_get_srid(geom), gserialized_has_z(geom), gserialized_has_m(geom));
+		result = geometry_serialize(lwpoint_as_lwgeom(lwg));
+		PG_RETURN_POINTER(result);
+	}
 
 	initGEOS(lwnotice, lwgeom_geos_error);
 
diff --git a/regress/tickets.sql b/regress/tickets.sql
index d9bf56c0b..9c2d112d5 100644
--- a/regress/tickets.sql
+++ b/regress/tickets.sql
@@ -346,8 +346,9 @@ SELECT '#682', ST_Buffer(ST_GeomFromText('POLYGON EMPTY',4326) , 0.5);
 -- #683 --
 SELECT '#683', ST_BuildArea(ST_GeomFromText('POINT EMPTY',4326));
 
--- #684 --
-SELECT '#684', ST_Centroid(ST_GeomFromText('POLYGON EMPTY',4326));
+-- #684,#2109 --
+SELECT '#684,#2109', ST_AsEWKT(ST_Centroid(ST_GeomFromText('POLYGON EMPTY',4326)));
+SELECT '#2109', ST_AsEWKT(ST_Centroid(ST_GeomFromText('MULTILINESTRING ZM EMPTY',3395)));
 
 -- #685 --
 SELECT '#685', ST_ConvexHull(ST_GeomFromText('POLYGON EMPTY',4326));
diff --git a/regress/tickets_expected b/regress/tickets_expected
index 387c95abe..b798bcb03 100644
--- a/regress/tickets_expected
+++ b/regress/tickets_expected
@@ -107,7 +107,8 @@ NOTICE:  IllegalArgumentException: Invalid number of points in LinearRing found
 #681g|
 #682|0103000020E610000000000000
 #683|0103000020E610000000000000
-#684|0103000020E610000000000000
+#684,#2109|SRID=4326;POINT EMPTY
+#2109|SRID=3395;POINT EMPTY
 #685|0103000020E610000000000000
 #686|0107000020E610000000000000
 #687|f