From f4e37b9742cc762c989f8896e14abc7901595835 Mon Sep 17 00:00:00 2001
From: Sandro Santilli <strk@keybit.net>
Date: Tue, 23 Feb 2016 15:53:12 +0000
Subject: [PATCH] Fix crash on face-collapsing edge change

See #3463

git-svn-id: http://svn.osgeo.org/postgis/trunk@14666 b70326c6-7e19-0410-871a-916f4a2858ee
---
 liblwgeom/lwgeom_topo.c | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/liblwgeom/lwgeom_topo.c b/liblwgeom/lwgeom_topo.c
index 2372319e0..d2741c36f 100644
--- a/liblwgeom/lwgeom_topo.c
+++ b/liblwgeom/lwgeom_topo.c
@@ -3586,6 +3586,13 @@ lwt_ChangeEdgeGeom(LWT_TOPOLOGY* topo, LWT_ELEMID edge_id, LWLINE *geom)
   if ( oldedge->face_left != 0 )
   {
     nface1 = lwt_GetFaceGeometry(topo, oldedge->face_left);
+    if ( ! nface1 )
+    {
+      lwerror("lwt_ChangeEdgeGeom could not construct face %"
+                 PRId64 ", on the left of edge %" PRId64,
+                oldedge->face_left, edge_id);
+      return -1;
+    }
 #if 0
     {
     size_t sz;
@@ -3604,6 +3611,13 @@ lwt_ChangeEdgeGeom(LWT_TOPOLOGY* topo, LWT_ELEMID edge_id, LWLINE *geom)
        && oldedge->face_right != oldedge->face_left )
   {
     nface2 = lwt_GetFaceGeometry(topo, oldedge->face_right);
+    if ( ! nface2 )
+    {
+      lwerror("lwt_ChangeEdgeGeom could not construct face %"
+                 PRId64 ", on the right of edge %" PRId64,
+                oldedge->face_right, edge_id);
+      return -1;
+    }
 #if 0
     {
     size_t sz;
-- 
2.40.0