[1.2.X] Fixed #14471 -- Corrected a regression in the use of methods on custom managers on related querysets. Thanks to Lucky for the report.

Backport of r14389 from trunk.

git-svn-id: http://code.djangoproject.com/svn/django/branches/releases/1.2.X@14390 bcc190cf-cafb-0310-a4f2-bffc1f526a37

django/db/models/fields/related.py

@@ -420,7 +420,7 @@ class ForeignRelatedObjectsDescriptor(object):
             def create(self, **kwargs):
                 kwargs.update({rel_field.name: instance})
                 db = router.db_for_write(rel_model, instance=instance)
-                return super(RelatedManager, self).using(db).create(**kwargs)
+                return super(RelatedManager, self.db_manager(db)).create(**kwargs)
             create.alters_data = True
 
             def get_or_create(self, **kwargs):
@@ -428,7 +428,7 @@ class ForeignRelatedObjectsDescriptor(object):
                 # ForeignRelatedObjectsDescriptor knows about.
                 kwargs.update({rel_field.name: instance})
                 db = router.db_for_write(rel_model, instance=instance)
-                return super(RelatedManager, self).using(db).get_or_create(**kwargs)
+                return super(RelatedManager, self.db_manager(db)).get_or_create(**kwargs)
             get_or_create.alters_data = True
 
             # remove() and clear() are only provided if the ForeignKey can have a value of null.
@@ -517,7 +517,7 @@ def create_many_related_manager(superclass, rel=False):
                 opts = through._meta
                 raise AttributeError("Cannot use create() on a ManyToManyField which specifies an intermediary model. Use %s.%s's Manager instead." % (opts.app_label, opts.object_name))
             db = router.db_for_write(self.instance.__class__, instance=self.instance)
-            new_obj = super(ManyRelatedManager, self).using(db).create(**kwargs)
+            new_obj = super(ManyRelatedManager, self.db_manager(db)).create(**kwargs)
             self.add(new_obj)
             return new_obj
         create.alters_data = True
@@ -525,7 +525,7 @@ def create_many_related_manager(superclass, rel=False):
         def get_or_create(self, **kwargs):
             db = router.db_for_write(self.instance.__class__, instance=self.instance)
             obj, created = \
-                super(ManyRelatedManager, self).using(db).get_or_create(**kwargs)
+                super(ManyRelatedManager, self.db_manager(db)).get_or_create(**kwargs)
             # We only need to add() if created because if we got an object back
             # from get() then the relationship already exists.
             if created:

tests/regressiontests/multiple_database/models.py

@@ -30,7 +30,21 @@ class Person(models.Model):
     class Meta:
         ordering = ('name',)
 
+# This book manager doesn't do anything interesting; it just
+# exists to strip out the 'extra_arg' argument to certain
+# calls. This argument is used to establish that the BookManager
+# is actually getting used when it should be.
+class BookManager(models.Manager):
+    def create(self, *args, **kwargs):
+        kwargs.pop('extra_arg', None)
+        return super(BookManager, self).create(*args, **kwargs)
+
+    def get_or_create(self, *args, **kwargs):
+        kwargs.pop('extra_arg', None)
+        return super(BookManager, self).get_or_create(*args, **kwargs)
+
 class Book(models.Model):
+    objects = BookManager()
     title = models.CharField(max_length=100)
     published = models.DateField()
     authors = models.ManyToManyField(Person)
@@ -60,4 +74,3 @@ class UserProfile(models.Model):
 
     class Meta:
         ordering = ('flavor',)
-

tests/regressiontests/multiple_database/tests.py

@@ -890,6 +890,28 @@ class QueryTestCase(TestCase):
         except ValueError:
             pass
 
+    def test_related_manager(self):
+        "Related managers return managers, not querysets"
+        mark = Person.objects.using('other').create(name="Mark Pilgrim")
+
+        # extra_arg is removed by the BookManager's implementation of
+        # create(); but the BookManager's implementation won't get called
+        # unless edited returns a Manager, not a queryset
+        mark.book_set.create(title="Dive into Python",
+                             published=datetime.date(2009, 5, 4),
+                             extra_arg=True)
+
+        mark.book_set.get_or_create(title="Dive into Python",
+                                    published=datetime.date(2009, 5, 4),
+                                    extra_arg=True)
+
+        mark.edited.create(title="Dive into Water",
+                           published=datetime.date(2009, 5, 4),
+                           extra_arg=True)
+
+        mark.edited.get_or_create(title="Dive into Water",
+                                  published=datetime.date(2009, 5, 4),
+                                  extra_arg=True)
 
 class TestRouter(object):
     # A test router. The behaviour is vaguely master/slave, but the