Fixed #11827: Can now calculate extent in Oracle on tables with one point.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@11577 bcc190cf-cafb-0310-a4f2-bffc1f526a37

django/contrib/gis/db/models/sql/aggregates.py

@@ -32,11 +32,20 @@ elif SpatialBackend.oracle:
 
     def convert_extent(clob):
         if clob:
-            # Oracle returns a polygon for the extent, we construct
-            # the 4-tuple from the coordinates in the polygon.
-            poly = SpatialBackend.Geometry(clob.read())
-            shell = poly.shell
-            ll, ur = shell[0], shell[2]
+            # Generally, Oracle returns a polygon for the extent -- however,
+            # it can return a single point if there's only one Point in the
+            # table.
+            ext_geom = SpatialBackend.Geometry(clob.read())
+            gtype = str(ext_geom.geom_type)
+            if gtype == 'Polygon':
+                # Construct the 4-tuple from the coordinates in the polygon.
+                shell = ext_geom.shell
+                ll, ur = shell[0][:2], shell[2][:2]
+            elif gtype == 'Point':
+                ll = ext_geom.coords[:2]
+                ur = ll
+            else:
+                raise Exception('Unexpected geometry type returned for extent: %s' % gtype)
             xmin, ymin = ll
             xmax, ymax = ur
             return (xmin, ymin, xmax, ymax)

django/contrib/gis/tests/geoapp/test_regress.py

@@ -1,6 +1,6 @@
 import os, unittest
 from django.contrib.gis.db.backend import SpatialBackend
-from django.contrib.gis.tests.utils import no_mysql, no_oracle, no_postgis
+from django.contrib.gis.tests.utils import no_mysql, no_oracle, no_postgis, no_spatialite
 from django.contrib.gis.shortcuts import render_to_kmz
 from models import City
 
@@ -27,3 +27,9 @@ class GeoRegressionTests(unittest.TestCase):
                   }]
         kmz = render_to_kmz('gis/kml/placemarks.kml', {'places' : places})
 
+    @no_spatialite
+    def test03_extent(self):
+        "Testing `extent` on a table with a single point, see #11827."
+        pnt = City.objects.get(name='Pueblo').point
+        ref_ext = (pnt.x, pnt.y, pnt.x, pnt.y)
+        self.assertEqual(ref_ext, City.objects.filter(name='Pueblo').extent())