[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.

3 files changed, 13 insertions, 0 deletions

diff --git a/django/contrib/gis/db/backends/base/adapter.py b/django/contrib/gis/db/backends/base/adapter.py
index ca77124351..25f8846fa8 100644
--- a/django/contrib/gis/db/backends/base/adapter.py
+++ b/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
 
diff --git a/django/contrib/gis/db/backends/postgis/adapter.py b/django/contrib/gis/db/backends/postgis/adapter.py
index 172133693b..1fd0ee1cce 100644
--- a/django/contrib/gis/db/backends/postgis/adapter.py
+++ b/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()
 
diff --git a/django/db/models/sql/compiler.py b/django/db/models/sql/compiler.py
index f1bb10e228..a695025167 100644
--- a/django/db/models/sql/compiler.py
+++ b/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