[1.8.x] Fixed #24615 -- ordering by expression not part of SELECT

Fixed queries where an expression was used in order_by() but the
expression wasn't in the query's select clause (for example the
expression could be masked by .values() call)

Thanks to Trac alias MattBlack85 for the report.
Backport of fb5c7748da from master.

django/contrib/gis/db/backends/base/adapter.py

@@ -12,6 +12,9 @@ class WKTAdapter(object):
             return False
         return self.wkt == other.wkt and self.srid == other.srid
 
+    def __hash__(self):
+        return hash((self.wkt, self.srid))
+
     def __str__(self):
         return self.wkt
 

django/contrib/gis/db/backends/postgis/adapter.py

@@ -28,6 +28,9 @@ class PostGISAdapter(object):
             return False
         return (self.ewkb == other.ewkb) and (self.srid == other.srid)
 
+    def __hash__(self):
+        return hash((self.ewkb, self.srid))
+
     def __str__(self):
         return self.getquoted()
 

django/db/models/sql/compiler.py

@@ -253,10 +253,17 @@ class SQLCompiler(object):
             descending = True if order == 'DESC' else False
 
             if col in self.query.annotation_select:
+                # Reference to expression in SELECT clause
                 order_by.append((
                     OrderBy(Ref(col, self.query.annotation_select[col]), descending=descending),
                     True))
                 continue
+            if col in self.query.annotations:
+                # References to an expression which is masked out of the SELECT clause
+                order_by.append((
+                    OrderBy(self.query.annotations[col], descending=descending),
+                    False))
+                continue
 
             if '.' in field:
                 # This came in through an extra(order_by=...) addition. Pass it

docs/releases/1.8.1.txt

@@ -49,3 +49,7 @@ Bugfixes
   remove usage of referencing views by dotted path in
   :func:`~django.conf.urls.url` which is deprecated in Django 1.8
   (:ticket:`24635`).
+
+* Fixed queries where an expression was referenced in ``order_by()``, but wasn't
+  part of the select clause. An example query is
+  ``qs.annotate(foo=F('field')).values('pk').order_by('foo'))`` (:ticket:`24615`).

tests/gis_tests/distapp/tests.py

@@ -1,6 +1,6 @@
 from __future__ import unicode_literals
 
-from django.contrib.gis.geos import HAS_GEOS
+from django.contrib.gis.geos import HAS_GEOS, Point
 from django.contrib.gis.measure import D  # alias for Distance
 from django.db import connection
 from django.db.models import Q
@@ -383,3 +383,10 @@ class DistanceTest(TestCase):
         z = SouthTexasZipcode.objects.distance(htown.point).area().get(name='78212')
         self.assertIsNone(z.distance)
         self.assertIsNone(z.area)
+
+    @skipUnlessDBFeature("has_distance_method")
+    def test_distance_order_by(self):
+        qs = SouthTexasCity.objects.distance(Point(3, 3)).order_by(
+            'distance'
+        ).values_list('name', flat=True).filter(name__in=('San Antonio', 'Pearland'))
+        self.assertQuerysetEqual(qs, ['San Antonio', 'Pearland'], lambda x: x)