From 3f8f3f8411650bd328cd4054941c18ff9da1d1f6 Mon Sep 17 00:00:00 2001
From: Justin Bronn <jbronn@gmail.com>
Date: Tue, 10 Nov 2009 17:28:20 +0000
Subject: [PATCH] Now raise an exception when trying to export 3D (HEX)EWKB
 when using GEOS 3.0 due to bug in that underlying library version.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@11731 bcc190cf-cafb-0310-a4f2-bffc1f526a37
---
 django/contrib/gis/geos/geometry.py        |  6 +++++
 django/contrib/gis/geos/tests/test_geos.py | 26 ++++++++++++++++++----
 2 files changed, 28 insertions(+), 4 deletions(-)

diff --git a/django/contrib/gis/geos/geometry.py b/django/contrib/gis/geos/geometry.py
index fb686741c5..9f2a119c47 100644
--- a/django/contrib/gis/geos/geometry.py
+++ b/django/contrib/gis/geos/geometry.py
@@ -389,6 +389,9 @@ class GEOSGeometry(GEOSBase, ListMixin):
         geometry.
         """
         if self.hasz:
+            if not GEOS_PREPARE:
+                # See: http://trac.osgeo.org/geos/ticket/216
+                raise GEOSException('Upgrade GEOS to 3.1 to get valid 3D HEXEWKB.')               
             return ewkb_w3d.write_hex(self)
         else:
             return ewkb_w.write_hex(self)
@@ -422,6 +425,9 @@ class GEOSGeometry(GEOSBase, ListMixin):
         and Z values that are a part of this geometry.
         """
         if self.hasz:
+            if not GEOS_PREPARE:
+                # See: http://trac.osgeo.org/geos/ticket/216
+                raise GEOSException('Upgrade GEOS to 3.1 to get valid 3D EWKB.')
             return ewkb_w3d.write(self)
         else:
             return ewkb_w.write(self)
diff --git a/django/contrib/gis/geos/tests/test_geos.py b/django/contrib/gis/geos/tests/test_geos.py
index 85f983733d..440075dd49 100644
--- a/django/contrib/gis/geos/tests/test_geos.py
+++ b/django/contrib/gis/geos/tests/test_geos.py
@@ -84,16 +84,34 @@ class GEOSTest(unittest.TestCase):
 
         # HEXEWKB should be appropriate for its dimension -- have to use an
         # a WKBWriter w/dimension set accordingly, else GEOS will insert
-        # garbage into 3D coordinate if there is none.
+        # garbage into 3D coordinate if there is none.  Also, GEOS has a
+        # a bug in versions prior to 3.1 that puts the X coordinate in
+        # place of Z; an exception should be raised on those versions.
         self.assertEqual(hexewkb_2d, pnt_2d.hexewkb)
-        self.assertEqual(hexewkb_3d, pnt_3d.hexewkb)
+        if GEOS_PREPARE:
+            self.assertEqual(hexewkb_3d, pnt_3d.hexewkb)
+            self.assertEqual(True, GEOSGeometry(hexewkb_3d).hasz)
+        else:
+            try:
+                hexewkb = pnt_3d.hexewkb
+            except GEOSException:
+                pass
+            else:
+                self.fail('Should have raised GEOSException.')
 
         # Same for EWKB.
         self.assertEqual(buffer(a2b_hex(hexewkb_2d)), pnt_2d.ewkb)
-        self.assertEqual(buffer(a2b_hex(hexewkb_3d)), pnt_3d.ewkb)
+        if GEOS_PREPARE:
+            self.assertEqual(buffer(a2b_hex(hexewkb_3d)), pnt_3d.ewkb)
+        else:
+            try:
+                ewkb = pnt_3d.ewkb
+            except GEOSException:
+                pass
+            else:
+                self.fail('Should have raised GEOSException')
         
         # Redundant sanity check.
-        self.assertEqual(True, GEOSGeometry(hexewkb_3d).hasz)
         self.assertEqual(4326, GEOSGeometry(hexewkb_2d).srid)
 
     def test01c_kml(self):