Allow overriding model's default ordering

bread/bread.py

@@ -265,8 +265,9 @@ def get_queryset(self):
                                 (prefix, self.get_sort_field_name_for_column(column_number)))
             # Add any ordering from the model's Meta data that isn't already included.
             # That will make the rest of the sort stable, if the model has some default sort order.
+            default_ordering = getattr(self, 'default_ordering', qset.model._meta.ordering)
             order_by_without_leading_dashes = [x.lstrip('-') for x in order_by]
-            for order_spec in qset.model._meta.ordering:
+            for order_spec in default_ordering:
                 if order_spec.lstrip('-') not in order_by_without_leading_dashes:
                     order_by.append(order_spec)
             qset = qset.order_by(*order_by)

docs/changes.rst

@@ -3,6 +3,12 @@
 Change Log
 ==========
 
+0.5.1 - Dec 1, 2017
+-------------------
+
+* Allow specifying default ordering on views for cases when we
+  don't control the model and can't change the ordering there.
+
 0.5.0 - Nov 30, 2017
 --------------------
 

docs/configuration.rst

@@ -194,6 +194,10 @@ sorting
     (Otherwise, every time we show a new page, we could be working off a different
     sorting of the results!)  If nothing else, include a sort on the primary key.
 
+    If you do not have control of the model and so cannot change its ordering there,
+    you can add a ``default_ordering`` attribute to the browse view. Bread will use that
+    if present, instead of the model's ordering.
+
     Configuring the browse view:
 
     If the second item in the ``columns`` entry for a column is not a valid specification

tests/test_browse.py

@@ -80,6 +80,36 @@ def test_sort_all_ascending(self, mock_logger):
         # No exceptions logged
         self.assertFalse(mock_logger.exception.called)
 
+    @patch('bread.templatetags.bread_tags.logger')
+    def test_sort_most_ascending_with_override_default_order(self, mock_logger):
+        self.set_urls(self.bread)
+        self.bread.browse_view.default_ordering = ['-other__text', 'age']
+        BreadTestModelFactory(name='999', other__text='012', age=50)
+        BreadTestModelFactory(name='555', other__text='333', age=60)
+        BreadTestModelFactory(name='111', other__text='555', age=10)
+        BreadTestModelFactory(name='111', other__text='555', age=20)
+        BreadTestModelFactory(name='111', other__text='555', age=5)
+        self.give_permission('browse')
+        url = reverse(self.bread.get_url_name('browse')) + '?o=0,1'
+        request = self.request_factory.get(url)
+        request.user = self.user
+        rsp = self.bread.get_browse_view()(request)
+        self.assertEqual(OK, rsp.status_code)
+        rsp.render()
+        results = rsp.context_data['object_list']
+
+        i = 0
+        while i < len(results) - 1:
+            sortA = (results[i].name, results[i].other.text)
+            sortB = (results[i+1].name, results[i+1].other.text)
+            self.assertLessEqual(sortA, sortB)
+            if sortA == sortB:
+                # default sort is 'age'
+                self.assertLessEqual(results[i].age, results[i+1].age)
+            i += 1
+        # No exceptions logged
+        self.assertFalse(mock_logger.exception.called)
+
     @patch('bread.templatetags.bread_tags.logger')
     def test_sort_all_descending(self, mock_logger):
         self.set_urls(self.bread)