From 59eb1b009d90f517b066c756e085d6ea05292197 Mon Sep 17 00:00:00 2001
From: Sandro Santilli <strk@keybit.net>
Date: Thu, 29 Dec 2011 18:13:07 +0000
Subject: [PATCH] Retain type of TopoGeometry objects defined by NO element
 (#1017)

Includes regression tests for conversion of typed empty objects
from simple to topological model.

git-svn-id: http://svn.osgeo.org/postgis/trunk@8614 b70326c6-7e19-0410-871a-916f4a2858ee
---
 topology/test/regress/createtopogeom.sql      | 7 +++++++
 topology/test/regress/createtopogeom_expected | 4 ++++
 topology/topology.sql.in.c                    | 9 +++++++++
 3 files changed, 20 insertions(+)

diff --git a/topology/test/regress/createtopogeom.sql b/topology/test/regress/createtopogeom.sql
index 0d8157301..29eb6b842 100644
--- a/topology/test/regress/createtopogeom.sql
+++ b/topology/test/regress/createtopogeom.sql
@@ -60,4 +60,11 @@ SELECT 'ML', ST_AsText(CreateTopoGeom( 'MiX', 2, 4, '{{1,2}}')); -- fine line
 SELECT 'MA', ST_AsText(CreateTopoGeom( 'MiX', 3, 4, '{{1,3}}')); -- fine area
 SELECT 'MM', ST_AsText(CreateTopoGeom( 'MiX', 4, 4, '{{1,3},{1,2},{1,1}}')); -- fine mix
 
+-- Test emptyness {
+SELECT 'POINT EMPTY', ST_AsEWKT( CreateTopoGeom( 'MiX', 1, 4, '{{0,0}}' ) );
+SELECT 'LINESTRING EMPTY', ST_AsEWKT( CreateTopoGeom( 'MiX', 2, 4, '{{0,0}}' ) );
+SELECT 'POLYGON EMPTY', ST_AsEWKT( CreateTopoGeom( 'MiX', 3, 4, '{{0,0}}' ) );
+SELECT 'GEOMETRYCOLLECTION EMPTY', ST_AsEWKT( CreateTopoGeom( 'MiX', 4, 4, '{{0,0}}' ) );
+-- } Test emptyness 
+
 SELECT DropTopology('MiX');
diff --git a/topology/test/regress/createtopogeom_expected b/topology/test/regress/createtopogeom_expected
index 7e5a6b3c5..b422a5438 100644
--- a/topology/test/regress/createtopogeom_expected
+++ b/topology/test/regress/createtopogeom_expected
@@ -25,4 +25,8 @@ MP|POINT(0 0)
 ML|LINESTRING(0 0,10 0)
 MA|POLYGON((10 0,0 0,5 5,10 0))
 MM|GEOMETRYCOLLECTION EMPTY
+POINT EMPTY|POINT EMPTY
+LINESTRING EMPTY|LINESTRING EMPTY
+POLYGON EMPTY|POLYGON EMPTY
+GEOMETRYCOLLECTION EMPTY|GEOMETRYCOLLECTION EMPTY
 Topology 'MiX' dropped
diff --git a/topology/topology.sql.in.c b/topology/topology.sql.in.c
index 8c678cff2..f26d6be99 100644
--- a/topology/topology.sql.in.c
+++ b/topology/topology.sql.in.c
@@ -1239,6 +1239,9 @@ BEGIN
 		LOOP
 			geom := rec.g;
 		END LOOP;
+		IF geom IS NULL THEN
+			geom := 'POLYGON EMPTY';
+		END IF;
 
 	ELSIF topogeom.type = 2 THEN -- [multi]line
 		FOR rec IN EXECUTE 'SELECT ST_LineMerge(ST_Collect(e.geom)) as g FROM '
@@ -1251,6 +1254,9 @@ BEGIN
 		LOOP
 			geom := rec.g;
 		END LOOP;
+		IF geom IS NULL THEN
+			geom := 'LINESTRING EMPTY';
+		END IF;
 	
 	ELSIF topogeom.type = 1 THEN -- [multi]point
 		FOR rec IN EXECUTE 'SELECT st_union(n.geom) as g FROM '
@@ -1263,6 +1269,9 @@ BEGIN
 		LOOP
 			geom := rec.g;
 		END LOOP;
+		IF geom IS NULL THEN
+			geom := 'POINT EMPTY';
+		END IF;
 
 	ELSE
 		RAISE NOTICE 'Geometry from TopoGeometry does not support TopoGeometries of type % so far', topogeom.type;
-- 
2.40.0