[1.9.x] Fixed #26212 -- Made forms.FileField and translation.lazy_number() picklable.

Backport of b59f963ad2 from master

django/utils/translation/__init__.py

@@ -106,6 +106,8 @@ def lazy_number(func, resultclass, number=None, **kwargs):
         kwargs['number'] = number
         proxy = lazy(func, resultclass)(**kwargs)
     else:
+        original_kwargs = kwargs.copy()
+
         class NumberAwareString(resultclass):
             def __mod__(self, rhs):
                 if isinstance(rhs, dict) and number:
@@ -128,9 +130,14 @@ def lazy_number(func, resultclass, number=None, **kwargs):
                 return translated
 
         proxy = lazy(lambda **kwargs: NumberAwareString(), NumberAwareString)(**kwargs)
+        proxy.__reduce__ = lambda: (_lazy_number_unpickle, (func, resultclass, number, original_kwargs))
     return proxy
 
 
+def _lazy_number_unpickle(func, resultclass, number, kwargs):
+    return lazy_number(func, resultclass, number=number, **kwargs)
+
+
 def ngettext_lazy(singular, plural, number=None):
     return lazy_number(ngettext, str, singular=singular, plural=plural, number=number)
 

docs/releases/1.8.10.txt

@@ -14,3 +14,6 @@ Bugfixes
 
 * Added system checks for query name clashes of hidden relationships
   (:ticket:`26162`).
+
+* Made ``forms.FileField`` and ``utils.translation.lazy_number()`` picklable
+  (:ticket:`26212`).

docs/releases/1.9.3.txt

@@ -24,3 +24,6 @@ Bugfixes
 
 * Fixed regression with an ``__in=qs`` lookup for a ``ForeignKey`` with
   ``to_field`` set (:ticket:`26196`).
+
+* Made ``forms.FileField`` and ``utils.translation.lazy_number()`` picklable
+  (:ticket:`26212`).

tests/forms_tests/tests/test_fields.py

@@ -919,6 +919,9 @@ class FieldsTests(SimpleTestCase):
         # with here)
         self.assertTrue(f.has_changed('resume.txt', {'filename': 'resume.txt', 'content': 'My resume'}))
 
+    def test_file_picklable(self):
+        self.assertIsInstance(pickle.loads(pickle.dumps(FileField())), FileField)
+
     # ImageField ##################################################################
 
     @skipIf(Image is None, "Pillow is required to test ImageField")

tests/i18n/tests.py

@@ -239,6 +239,14 @@ class TranslationTests(SimpleTestCase):
         )
         self.assertEqual(result % {'name': 'Joe', 'num': 4}, "Joe has 4 good results")
 
+    def test_ungettext_lazy_pickle(self):
+        s1 = ungettext_lazy('%d good result', '%d good results')
+        self.assertEqual(s1 % 1, '1 good result')
+        self.assertEqual(s1 % 8, '8 good results')
+        s2 = pickle.loads(pickle.dumps(s1))
+        self.assertEqual(s2 % 1, '1 good result')
+        self.assertEqual(s2 % 8, '8 good results')
+
     @override_settings(LOCALE_PATHS=extended_locale_paths)
     def test_pgettext(self):
         trans_real._active = local()