Fixed #17976 -- Made forms.BooleanField pickleable.

This was a regression in Django 1.4.
Thanks bronger for the report and claudep for the patch.

django/forms/widgets.py

@@ -487,15 +487,18 @@ class TimeInput(Input):
             pass
         return super(TimeInput, self)._has_changed(self._format_value(initial), data)
 
+
+# Defined at module level so that CheckboxInput is picklable (#17976)
+def boolean_check(v):
+    return not (v is False or v is None or v == '')
+
+
 class CheckboxInput(Widget):
     def __init__(self, attrs=None, check_test=None):
         super(CheckboxInput, self).__init__(attrs)
         # check_test is a callable that takes a value and returns True
         # if the checkbox should be checked for that value.
-        if check_test is None:
-            self.check_test = lambda v: not (v is False or v is None or v == '')
-        else:
-            self.check_test = check_test
+        self.check_test = boolean_check if check_test is None else check_test
 
     def render(self, name, value, attrs=None):
         final_attrs = self.build_attrs(attrs, type='checkbox', name=name)

tests/regressiontests/forms/tests/fields.py

@@ -25,6 +25,7 @@ Other than that, the Field subclasses have class-specific options for
 __init__(). For example, CharField has a max_length option.
 """
 import datetime
+import pickle
 import re
 import os
 import warnings
@@ -690,6 +691,9 @@ class FieldsTests(SimpleTestCase):
         self.assertEqual(False, f.clean('false'))
         self.assertEqual(False, f.clean('FaLsE'))
 
+    def test_boolean_picklable(self):
+        self.assertIsInstance(pickle.loads(pickle.dumps(BooleanField())), BooleanField)
+
     # ChoiceField #################################################################
 
     def test_choicefield_1(self):