Remove OrderingFilter.help_text (#757)

* Remove confusing help text for OrderingFilter

* Add OrderingFilter/SelectMultiple incompat note

django_filters/filters.py

@@ -618,6 +618,7 @@ def __init__(self, *args, **kwargs):
             kwargs['choices'] = self.build_choices(fields, field_labels)
 
         kwargs.setdefault('label', _('Ordering'))
+        kwargs.setdefault('help_text', '')
         kwargs.setdefault('null_label', None)
         super(OrderingFilter, self).__init__(*args, **kwargs)
 

docs/ref/filters.txt

@@ -757,7 +757,8 @@ want to disable descending sort options.
 
 This filter is also CSV-based, and accepts multiple ordering params. The
 default select widget does not enable the use of this, but it is useful
-for APIs.
+for APIs. ``SelectMultiple`` widgets are not compatible, given that they
+are not able to retain selection order.
 
 Adding Custom filter choices
 """"""""""""""""""""""""""""

tests/test_filters.py

@@ -1411,3 +1411,8 @@ def test_translation_override_label(self):
                 ('username', 'BLABLA'),
                 ('-username', 'BLABLA (malejąco)'),
             ])
+
+    def test_help_text(self):
+        # regression test for #756 - the ususal CSV help_text is not relevant to ordering filters.
+        self.assertEqual(OrderingFilter().field.help_text, '')
+        self.assertEqual(OrderingFilter(help_text='a').field.help_text, 'a')