Refs #14357 -- Deprecated Meta.ordering affecting GROUP BY queries.

Thanks Ramiro Morales for contributing to the patch.

docs/internals/deprecation.txt

@@ -19,6 +19,8 @@ details on these changes.
 
 * ``django.core.paginator.QuerySetPaginator`` will be removed.
 
+* A model's ``Meta.ordering`` will no longer affect ``GROUP BY`` queries.
+
 .. _deprecation-removed-in-3.0:
 
 3.0

docs/ref/models/options.txt

@@ -285,7 +285,8 @@ Django quotes column and table names behind the scenes.
         ordering = [F('author').asc(nulls_last=True)]
 
     Default ordering also affects :ref:`aggregation queries
-    <aggregation-ordering-interaction>`.
+    <aggregation-ordering-interaction>` but this won't be the case starting
+    in Django 3.1.
 
 .. warning::
 

docs/releases/2.2.txt

@@ -289,6 +289,15 @@ Miscellaneous
 Features deprecated in 2.2
 ==========================
 
+Model ``Meta.ordering`` will no longer affect ``GROUP BY`` queries
+------------------------------------------------------------------
+
+A model's ``Meta.ordering`` affecting ``GROUP BY`` queries (such as
+``.annotate().values()``) is a common source of confusion. Such queries now
+issue a deprecation warning with the advice to add an ``order_by()`` to retain
+the current query. ``Meta.ordering`` will be ignored in such queries starting
+in Django 3.1.
+
 Miscellaneous
 -------------
 

docs/topics/db/aggregation.txt

@@ -514,6 +514,13 @@ include the aggregate column.
 Interaction with default ordering or ``order_by()``
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
+.. deprecated:: 2.2
+
+    Starting in Django 3.1, the ordering from a model's ``Meta.ordering`` won't
+    be used in ``GROUP BY`` queries, such as ``.annotate().values()``. Since
+    Django 2.2, these queries issue a deprecation warning indicating to add an
+    explicit ``order_by()`` to the queryset to silence the warning.
+
 Fields that are mentioned in the ``order_by()`` part of a queryset (or which
 are used in the default ordering on a model) are used when selecting the
 output data, even if they are not otherwise specified in the ``values()``