Ticket #6786: choices_order.diff

django/db/models/fields/__init__.py

@@ -82 +82 @@
         max_length=None, unique=False, blank=False, null=False, db_index=False,
         core=False, rel=None, default=NOT_PROVIDED, editable=True, serialize=True,
         prepopulate_from=None, unique_for_date=None, unique_for_month=None,
-        unique_for_year=None, validator_list=None, choices=None, radio_admin=None,
+        unique_for_year=None, validator_list=None, choices=None, order=None, radio_admin=None,
         help_text='', db_column=None, db_tablespace=None):
         self.name = name
         self.verbose_name = verbose_name
@@ -101 +101 @@
         self.unique_for_date, self.unique_for_month = unique_for_date, unique_for_month
         self.unique_for_year = unique_for_year
         self._choices = choices or []
+        self._order = order or False
         self.radio_admin = radio_admin
         self.help_text = help_text
         self.db_column = db_column
@@ -344 +345 @@
         "Returns a list of tuples used as SelectField choices for this field."
         first_choice = include_blank and blank_choice or []
         if self.choices:
-            return first_choice + list(self.choices)
-        rel_model = self.rel.to
-        if hasattr(self.rel, 'get_related_field'):
-            lst = [(getattr(x, self.rel.get_related_field().attname), smart_unicode(x)) for x in rel_model._default_manager.complex_filter(self.rel.limit_choices_to)]
+            lst = list(self.choices)
         else:
-            lst = [(x._get_pk_val(), smart_unicode(x)) for x in rel_model._default_manager.complex_filter(self.rel.limit_choices_to)]
+            rel_qset = self.rel.to._default_manager.complex_filter(self.rel.limit_choices_to)
+            if hasattr(self.rel, 'get_related_field'):
+                lst = [(getattr(x, self.rel.get_related_field().attname), smart_unicode(x)) for x in rel_qset]
+            else:
+                lst = [(x._get_pk_val(), smart_unicode(x)) for x in rel_qset]
+
+        # Order choices list either ascending or descending, depending on sign of non-callable self._order,
+        # or using callable self._order as an argument for sort funciton
+        if self._order:
+            local_order = self._order
+            local_order = callable(local_order) and local_order or (lambda x,y: cmp(x.lower(), y.lower()) * self._order)
+            lst.sort(lambda x,y: local_order(force_unicode(x[1]), force_unicode(y[1])))
+
         return first_choice + lst
 
     def get_choices_default(self):

docs/model-api.txt

@@ -580 +580 @@
 a proper database table with a ``ForeignKey``. ``choices`` is meant for static
 data that doesn't change much, if ever.
 
+``order``
+~~~~~~~~~~~
+
+**New in Django development version**
+
+Specifies ordering for the choices list of this field (when ``choices``
+argument is specified), or for available primary key labels (if the field is
+ForeignKey). Must be either an expression that could be evaluated as integer,
+or callable.
+
+If the argument is an expression that evaluates to 0 (default), ordering is
+not performed and choices list appears in widgets as is. Positive value
+represents ascending order, negative - descending. Both are case-insensitive.
+
+To implement custom ordering, this argument must be callable, that is used by
+Python sort method of list to compare two objects (see ``cmp`` in Python 
+documentation). The objects are converted to unicode before comparison.
+
+Ordering is applied to the list each time widget is rendering. So, the list is
+ordered after translation and localized lists are sorted correctly. At the
+same time extensive usage of this argument may affect productivity.
+
 ``core``
 ~~~~~~~~