Fixed #26230 -- Made default_related_name affect related_query_name.

django/db/models/fields/related.py

@@ -290,8 +290,13 @@ class RelatedField(Field):
 
         if not cls._meta.abstract:
             if self.remote_field.related_name:
-                related_name = force_text(self.remote_field.related_name) % {
+                related_name = self.remote_field.related_name
+            else:
+                related_name = self.opts.default_related_name
+            if related_name:
+                related_name = force_text(related_name) % {
                     'class': cls.__name__.lower(),
+                    'model_name': cls._meta.model_name.lower(),
                     'app_label': cls._meta.app_label.lower()
                 }
                 self.remote_field.related_name = related_name

django/db/models/fields/reverse_related.py

@@ -187,11 +187,6 @@ class ForeignObjectRel(object):
                 return None
         if self.related_name:
             return self.related_name
-        if opts.default_related_name:
-            return opts.default_related_name % {
-                'model_name': opts.model_name.lower(),
-                'app_label': opts.app_label.lower(),
-            }
         return opts.model_name + ('_set' if self.multiple else '')
 
     def get_cache_name(self):

django/db/models/sql/query.py

@@ -7,6 +7,7 @@ databases). The abstraction barrier only works one way: this module has to know
 all about the internals of models in order to get the information it needs.
 """
 import copy
+import warnings
 from collections import Counter, Iterator, Mapping, OrderedDict
 from itertools import chain, count, product
 from string import ascii_uppercase
@@ -30,6 +31,7 @@ from django.db.models.sql.where import (
     AND, OR, ExtraWhere, NothingNode, WhereNode,
 )
 from django.utils import six
+from django.utils.deprecation import RemovedInDjango20Warning
 from django.utils.encoding import force_text
 from django.utils.tree import Node
 
@@ -1288,6 +1290,19 @@ class Query(object):
             except FieldDoesNotExist:
                 if name in self.annotation_select:
                     field = self.annotation_select[name].output_field
+                elif pos == 0:
+                    for rel in opts.related_objects:
+                        if (name == rel.related_model._meta.model_name and
+                                rel.related_name == rel.related_model._meta.default_related_name):
+                            related_name = rel.related_name
+                            field = opts.get_field(related_name)
+                            warnings.warn(
+                                "Query lookup '%s' is deprecated in favor of "
+                                "Meta.default_related_name '%s'."
+                                % (name, related_name),
+                                RemovedInDjango20Warning, 2
+                            )
+                            break
 
             if field is not None:
                 # Fields that contain one-to-many relations with a generic

docs/internals/deprecation.txt

@@ -138,6 +138,9 @@ details on these changes.
 * Support for the ``django.core.files.storage.Storage.accessed_time()``,
   ``created_time()``, and ``modified_time()`` methods will be removed.
 
+* Support for query lookups using the model name when
+  ``Meta.default_related_name`` is set will be removed.
+
 .. _deprecation-removed-in-1.10:
 
 1.10

docs/ref/models/fields.txt

@@ -1333,8 +1333,9 @@ The possible values for :attr:`~ForeignKey.on_delete` are found in
 
 .. attribute:: ForeignKey.related_query_name
 
-    The name to use for the reverse filter name from the target model.
-    Defaults to the value of :attr:`related_name` if it is set, otherwise it
+    The name to use for the reverse filter name from the target model. It
+    defaults to the value of :attr:`related_name` or
+    :attr:`~django.db.models.Options.default_related_name` if set, otherwise it
     defaults to the name of the model::
 
         # Declare the ForeignKey with related_query_name

docs/ref/models/options.txt

@@ -103,6 +103,8 @@ Django quotes column and table names behind the scenes.
     The name that will be used by default for the relation from a related object
     back to this one. The default is ``<model_name>_set``.
 
+    This option also sets :attr:`~ForeignKey.related_query_name`.
+
     As the reverse name for a field should be unique, be careful if you intend
     to subclass your model. To work around name collisions, part of the name
     should contain ``'%(app_label)s'`` and ``'%(model_name)s'``, which are
@@ -110,6 +112,30 @@ Django quotes column and table names behind the scenes.
     and the name of the model, both lowercased. See the paragraph on
     :ref:`related names for abstract models <abstract-related-name>`.
 
+    .. deprecated:: 1.10
+
+        This attribute now affects ``related_query_name``. The old query lookup
+        name is deprecated::
+
+            from django.db import models
+
+            class Foo(models.Model):
+                pass
+
+            class Bar(models.Model):
+                foo = models.ForeignKey(Foo)
+
+                class Meta:
+                    default_related_name = 'bars'
+
+        ::
+
+            >>> bar = Bar.objects.get(pk=1)
+            >>> # Using model name "bar" as lookup string is deprecated.
+            >>> Foo.object.get(bar=bar)
+            >>> # You should use default_related_name "bars".
+            >>> Foo.object.get(bars=bar)
+
 ``get_latest_by``
 -----------------
 

docs/releases/1.10.txt

@@ -704,6 +704,34 @@ longer than the 4000 byte limit of ``NVARCHAR2``, you should use ``TextField``
 field (e.g. annotating the model with an aggregation or using ``distinct()``)
 you'll need to change them (to defer the field).
 
+Using a model name as a query lookup when ``default_related_name`` is set
+-------------------------------------------------------------------------
+
+Assume the following models::
+
+    from django.db import models
+
+    class Foo(models.Model):
+        pass
+
+    class Bar(models.Model):
+        foo = models.ForeignKey(Foo)
+
+        class Meta:
+            default_related_name = 'bars'
+
+In older versions, :attr:`~django.db.models.Options.default_related_name`
+couldn't be used as a query lookup. This is fixed and support for the old
+lookup name is deprecated. For example, since ``default_related_name`` is set
+in model ``Bar``, instead of using the model name ``bar`` as the lookup::
+
+    >>> bar = Bar.objects.get(pk=1)
+    >>> Foo.object.get(bar=bar)
+
+use the default_related_name ``bars``::
+
+    >>> Foo.object.get(bars=bar)
+
 Miscellaneous
 -------------
 

tests/model_options/test_default_related_name.py

@@ -1,4 +1,7 @@
+import warnings
+
 from django.test import TestCase
+from django.utils.deprecation import RemovedInDjango20Warning
 
 from .models.default_related_name import Author, Book, Editor
 
@@ -18,6 +21,19 @@ class DefaultRelatedNameTests(TestCase):
     def test_default_related_name(self):
         self.assertEqual(list(self.author.books.all()), [self.book])
 
+    def test_default_related_name_in_queryset_lookup(self):
+        self.assertEqual(Author.objects.get(books=self.book), self.author)
+
+    def test_show_deprecated_message_when_model_name_in_queryset_lookup(self):
+        msg = "Query lookup 'book' is deprecated in favor of Meta.default_related_name 'books'."
+        with warnings.catch_warnings(record=True) as warns:
+            warnings.simplefilter('once')
+            Author.objects.get(book=self.book)
+        self.assertEqual(len(warns), 1)
+        warning = warns.pop()
+        self.assertEqual(warning.category, RemovedInDjango20Warning)
+        self.assertEqual(str(warning.message), msg)
+
     def test_related_name_overrides_default_related_name(self):
         self.assertEqual(list(self.editor.edited_books.all()), [self.book])