Ticket #12568: subfieldbase-20130917.diff

django/db/models/fields/subclassing.py

@@ -30 +30 @@
 
     def __get__(self, obj, type=None):
         if obj is None:
-            raise AttributeError('Can only be accessed via an instance.')
+             return self
         return obj.__dict__[self.field.name]
 
     def __set__(self, obj, value):

tests/field_subclassing/tests.py

@@ -1 +1 @@
 from __future__ import unicode_literals
 
+import inspect
+
 from django.core import serializers
 from django.test import TestCase
 
@@ -90 +92 @@
         o = OtherModel.objects.get()
         self.assertEqual(o.data.first, "a")
         self.assertEqual(o.data.second, "b")
+
+    def test_subfieldbase_plays_nice_with_module_inspect(self):
+        """
+        Custom fields should play nice with python standard module inspect.
+
+        http://users.rcn.com/python/download/Descriptor.htm#properties
+        """
+        # even when looking for totally different properties, SubfieldBase it's
+        # non property like behaviour makes inspect crash.
+        strings = inspect.getmembers(MyModel, lambda x: type(x) is str)
+        known_strings = [('__module__', 'field_subclassing.models')]
+
+        self.assertEqual(strings, known_strings)
+
+        # should also not raise an exception
+        inspect.getmembers(MyModel)