Refs #7098 -- Deprecated passing raw column aliases to order_by().

Now that order_by() has expression support passing RawSQL() can achieve
the same result.

This was also already supported through QuerySet.extra(order_by) for
years but this API is more or less deprecated at this point.

tests/queries/tests.py

@@ -7,10 +7,12 @@ from operator import attrgetter
 from django.core.exceptions import EmptyResultSet, FieldError
 from django.db import DEFAULT_DB_ALIAS, connection
 from django.db.models import Count, Exists, F, OuterRef, Q
+from django.db.models.expressions import RawSQL
 from django.db.models.sql.constants import LOUTER
 from django.db.models.sql.where import NothingNode, WhereNode
 from django.test import SimpleTestCase, TestCase, skipUnlessDBFeature
-from django.test.utils import CaptureQueriesContext
+from django.test.utils import CaptureQueriesContext, ignore_warnings
+from django.utils.deprecation import RemovedInDjango40Warning
 
 from .models import (
     FK1, Annotation, Article, Author, BaseA, Book, CategoryItem,
@@ -609,14 +611,36 @@ class Queries1Tests(TestCase):
             ['datetime.datetime(2007, 12, 19, 0, 0)']
         )
 
+    @ignore_warnings(category=RemovedInDjango40Warning)
     def test_ticket7098(self):
-        # Make sure semi-deprecated ordering by related models syntax still
-        # works.
         self.assertSequenceEqual(
             Item.objects.values('note__note').order_by('queries_note.note', 'id'),
             [{'note__note': 'n2'}, {'note__note': 'n3'}, {'note__note': 'n3'}, {'note__note': 'n3'}]
         )
 
+    def test_order_by_rawsql(self):
+        self.assertSequenceEqual(
+            Item.objects.values('note__note').order_by(
+                RawSQL('queries_note.note', ()),
+                'id',
+            ),
+            [
+                {'note__note': 'n2'},
+                {'note__note': 'n3'},
+                {'note__note': 'n3'},
+                {'note__note': 'n3'},
+            ],
+        )
+
+    def test_order_by_raw_column_alias_warning(self):
+        msg = (
+            "Passing column raw column aliases to order_by() is deprecated. "
+            "Wrap 'queries_author.name' in a RawSQL expression before "
+            "passing it to order_by()."
+        )
+        with self.assertRaisesMessage(RemovedInDjango40Warning, msg):
+            Item.objects.values('creator__name').order_by('queries_author.name')
+
     def test_ticket7096(self):
         # Make sure exclude() with multiple conditions continues to work.
         self.assertQuerysetEqual(