From: Sandro Santilli <strk@keybit.net>
Date: Fri, 20 Jan 2012 14:47:24 +0000 (+0000)
Subject: Don't let ST_Multi create collections of a single EMPTY (#1489)
X-Git-Tag: 2.0.0alpha2~29
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=6ef84a957a94f281bb93bd0147f4ae50e6bc0965;p=postgis

Don't let ST_Multi create collections of a single EMPTY (#1489)

git-svn-id: http://svn.osgeo.org/postgis/trunk@8892 b70326c6-7e19-0410-871a-916f4a2858ee
---

diff --git a/liblwgeom/lwgeom.c b/liblwgeom/lwgeom.c
index cdea7bb7d..409c0f8e9 100644
--- a/liblwgeom/lwgeom.c
+++ b/liblwgeom/lwgeom.c
@@ -289,8 +289,6 @@ lwgeom_as_multi(const LWGEOM *lwgeom)
 	GBOX *box = NULL;
 	int type;
 
-	ogeoms = lwalloc(sizeof(LWGEOM*));
-
 	/*
 	** This funx is a no-op only if a bbox cache is already present
 	** in input.
@@ -302,8 +300,20 @@ lwgeom_as_multi(const LWGEOM *lwgeom)
 
 	type = lwgeom->type;
 
-	if ( MULTITYPE[type] )
+	if ( ! MULTITYPE[type] ) return lwgeom_clone(lwgeom);
+
+	if( lwgeom_is_empty(lwgeom) )
+	{
+		ogeom = (LWGEOM *)lwcollection_construct_empty(
+			MULTITYPE[type],
+			lwgeom->srid,
+			FLAGS_GET_Z(lwgeom->flags),
+			FLAGS_GET_M(lwgeom->flags)
+		);
+	}
+	else
 	{
+		ogeoms = lwalloc(sizeof(LWGEOM*));
 		ogeoms[0] = lwgeom_clone(lwgeom);
 
 		/* Sub-geometries are not allowed to have bboxes or SRIDs, move the bbox to the collection */
@@ -313,10 +323,6 @@ lwgeom_as_multi(const LWGEOM *lwgeom)
 
 		ogeom = (LWGEOM *)lwcollection_construct(MULTITYPE[type], lwgeom->srid, box, 1, ogeoms);
 	}
-	else
-	{
-		return lwgeom_clone(lwgeom);
-	}
 
 	return ogeom;
 }
diff --git a/regress/tickets.sql b/regress/tickets.sql
index 40c38c9b3..331930c82 100644
--- a/regress/tickets.sql
+++ b/regress/tickets.sql
@@ -551,6 +551,19 @@ select '#852.2', id, -- first run is not cached, consequent are cached
   st_intersects(g, 'POLYGON((0 0, 1 1, 1 0, 0 0))'::geometry) from cacheable;
 DROP TABLE cacheable;
 
+-- #1489
+with inp AS ( SELECT
+	st_multi('POINT EMPTY'::geometry) as mp,
+	st_multi('LINESTRING EMPTY'::geometry) as ml, 
+	st_multi('POLYGON EMPTY'::geometry) as ma,
+	st_multi('GEOMETRYCOLLECTION EMPTY'::geometry) as mm
+) select '#1489',
+	st_astext(mp), st_numgeometries(mp),
+	st_astext(ml), st_numgeometries(ml),
+	st_astext(ma), st_numgeometries(ma),
+	st_astext(mm), st_numgeometries(mm)
+FROM inp;
+
 -- Clean up
 DELETE FROM spatial_ref_sys;
 
diff --git a/regress/tickets_expected b/regress/tickets_expected
index da7dbff43..f85419f24 100644
--- a/regress/tickets_expected
+++ b/regress/tickets_expected
@@ -183,3 +183,4 @@ ERROR:  MultiSurface cannot contain MultiPoint element
 #852.1|2|f|f
 #852.2|1|t|t
 #852.2|2|t|t
+#1489|MULTIPOINT EMPTY|0|MULTILINESTRING EMPTY|0|MULTIPOLYGON EMPTY|0|GEOMETRYCOLLECTION EMPTY|0