Fixed #10594 -- `GeoQuerySet` measurment methods no longer crash on geometry fields with NULL values. Thanks, whiteinge for the bug report and yourcelf for the initial patch.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@12885 bcc190cf-cafb-0310-a4f2-bffc1f526a37

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

@@ -51,7 +51,8 @@ class GeoQuery(sql.Query):
         return obj
 
     def convert_values(self, value, field, connection):
-        """        Using the same routines that Oracle does we can convert our
+        """
+        Using the same routines that Oracle does we can convert our
         extra selection objects into Geometry and Distance objects.
         TODO: Make converted objects 'lazy' for less overhead.
         """
@@ -59,7 +60,11 @@ class GeoQuery(sql.Query):
             # Running through Oracle's first.
             value = super(GeoQuery, self).convert_values(value, field or GeomField(), connection)
 
-        if isinstance(field, DistanceField):
+        if value is None:
+            # Output from spatial function is NULL (e.g., called
+            # function on a geometry field with NULL value).
+            pass
+        elif isinstance(field, DistanceField):
             # Using the field's distance attribute, can instantiate
             # `Distance` with the right context.
             value = Distance(**{field.distance_att : value})

django/contrib/gis/tests/distapp/models.py

@@ -26,11 +26,12 @@ class CensusZipcode(models.Model):
     name = models.CharField(max_length=5)
     poly = models.PolygonField(srid=4269)
     objects = models.GeoManager()
+    def __unicode__(self): return self.name
 
 class SouthTexasZipcode(models.Model):
     "Model for a few South Texas ZIP codes."
     name = models.CharField(max_length=5)
-    poly = models.PolygonField(srid=32140)
+    poly = models.PolygonField(srid=32140, null=True)
     objects = models.GeoManager()
     def __unicode__(self): return self.name
 

django/contrib/gis/tests/distapp/tests.py

@@ -362,6 +362,17 @@ class DistanceTest(unittest.TestCase):
         for i, c in enumerate(SouthTexasCity.objects.perimeter(model_att='perim')):
             self.assertEqual(0, c.perim.m)
 
+    def test09_measurement_null_fields(self):
+        "Testing the measurement GeoQuerySet methods on fields with NULL values."
+        # Creating SouthTexasZipcode w/NULL value.
+        SouthTexasZipcode.objects.create(name='78212')
+        # Performing distance/area queries against the NULL PolygonField,
+        # and ensuring the result of the operations is None.
+        htown = SouthTexasCity.objects.get(name='Downtown Houston')
+        z = SouthTexasZipcode.objects.distance(htown.point).area().get(name='78212')
+        self.assertEqual(None, z.distance)
+        self.assertEqual(None, z.area)
+
 def suite():
     s = unittest.TestSuite()
     s.addTest(unittest.makeSuite(DistanceTest))