From: Raúl Marín Rodríguez <rmrodriguez@carto.com>
Date: Sat, 22 Sep 2018 13:00:41 +0000 (+0000)
Subject: St_AsMVTGeom: Avoid type changes due to validation
X-Git-Tag: 3.0.0alpha1~391
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=bcbf7b193f66f29afa983602cb537316b6c2fd79;p=postgis

St_AsMVTGeom: Avoid type changes due to validation

References #4181
Closes https://github.com/postgis/postgis/pull/304/


git-svn-id: http://svn.osgeo.org/postgis/trunk@16831 b70326c6-7e19-0410-871a-916f4a2858ee
---

diff --git a/NEWS b/NEWS
index aac36ed56..9cc164ffd 100644
--- a/NEWS
+++ b/NEWS
@@ -18,6 +18,7 @@ PostGIS 3.0.0
   - #4176, ST_Intersects supports GEOMETRYCOLLECTION (Darafei Praliaskouski)
   - #4177, Postgres 12 disallows variable length arrays in C (Laurenz Albe)
   - #4160, Use qualified names in topology extension install (Raúl Marín)
+  - #4181, St_AsMVTGeom: Avoid type changes due to validation (Raúl Marín)
 
 PostGIS 2.5.0rc1
 2018/08/19
diff --git a/postgis/mvt.c b/postgis/mvt.c
index 9ebc61882..8468b05a7 100644
--- a/postgis/mvt.c
+++ b/postgis/mvt.c
@@ -921,14 +921,24 @@ LWGEOM *mvt_geom(LWGEOM *lwgeom, const GBOX *gbox, uint32_t extent, uint32_t buf
 	if (lwgeom == NULL || lwgeom_is_empty(lwgeom))
 		return NULL;
 
-	/* if polygon(s) make valid and force clockwise as per MVT spec */
+
 	if (lwgeom->type == POLYGONTYPE ||
 		lwgeom->type == MULTIPOLYGONTYPE ||
 		lwgeom->type == COLLECTIONTYPE)
 	{
+		/* Force validation as per MVT spec */
 		lwgeom = lwgeom_make_valid(lwgeom);
-		/* In image coordinates CW actually comes out a CCW, so */
-		/* we also reverse. ¯\_(ツ)_/¯ */
+
+		/* Drop type changes tp play nice with MVT renderers */
+		if (!(lwgeom->type == POLYGONTYPE ||
+			lwgeom->type == MULTIPOLYGONTYPE ||
+			lwgeom->type == COLLECTIONTYPE))
+		{
+			lwgeom_free(lwgeom);
+			return NULL;
+		}
+
+		/* In image coordinates CW actually comes out a CCW, so we reverse */
 		lwgeom_force_clockwise(lwgeom);
 		lwgeom_reverse_in_place(lwgeom);
 	}
diff --git a/regress/mvt.sql b/regress/mvt.sql
index 7b9b4e222..dcc237a79 100644
--- a/regress/mvt.sql
+++ b/regress/mvt.sql
@@ -257,6 +257,14 @@ SELECT 'PG43 - OFF', ST_AsText(ST_AsMVTGeom(
 	ST_MakeBox2D(ST_Point(0, 0), ST_Point(100, 100)),
 	10, 0, false));
 
+-- Geometry type change
+SELECT 'PG44', ST_AsEWKT(ST_AsMVTGeom(
+	'SRID=3857;MULTIPOLYGON(((-8238038.43842083 4974073.00356281,-8238058.59985694 4974035.91194892,-8238046.74211362 4974077.68076013,-8238038.43842083 4974073.00356281)))'::geometry,
+	'SRID=3857;POLYGON((-8242969.13027341 4975133.29702555,-8242969.13027341 4970241.3272153,-8238077.16046316 4970241.3272153,-8238077.16046316 4975133.29702555,-8242969.13027341 4975133.29702555))'::geometry,
+	4096,
+	16,
+	true));
+
 -- geometry encoding tests
 SELECT 'TG1', encode(ST_AsMVT(q, 'test', 4096, 'geom'), 'base64') FROM (SELECT 1 AS c1,
 	ST_AsMVTGeom(ST_GeomFromText('POINT(25 17)'),
@@ -485,4 +493,4 @@ SELECT 'FI9', encode(ST_AsMVT(q, 'test', 4096, 'geom', 'c1'), 'base64') FROM (
 	SELECT 1::double precision AS c1, 'abcd'::text AS c2, 20::integer as c1,
 	ST_AsMVTGeom(ST_GeomFromText('POINT(25 17)'),
 		ST_MakeBox2D(ST_Point(0, 0), ST_Point(4096, 4096)), 4096, 0, false) AS geom
-) AS q;
\ No newline at end of file
+) AS q;
diff --git a/regress/mvt_expected b/regress/mvt_expected
index 75b6cb95d..6b711466b 100644
--- a/regress/mvt_expected
+++ b/regress/mvt_expected
@@ -46,6 +46,7 @@ PG42 - ON |LINESTRING(0 10,0 0,1 0)
 PG42 - OFF|LINESTRING(0 10,0 0,1 0)
 PG43 - ON |MULTIPOLYGON(((5 5,0 0,10 0,5 5)),((0 10,5 5,10 10,0 10)))
 PG43 - OFF|MULTIPOLYGON(((5 5,-1 -1,11 -1,5 5)),((5 5,11 11,-1 11,5 5)))
+PG44|
 TG1|GiEKBHRlc3QSDBICAAAYASIECTLePxoCYzEiAigBKIAgeAI=
 TG2|GiMKBHRlc3QSDhICAAAYASIGETLePwIBGgJjMSICKAEogCB4Ag==
 TG3|GiYKBHRlc3QSERICAAAYAiIJCQCAQArQD88PGgJjMSICKAEogCB4Ag==