Fixed #21200 -- Consistantly raise errors across all cache backends.

Thanks to tchaumeny for the patch.

docs/releases/1.7.txt

@@ -536,6 +536,18 @@ For apps with migrations, ``allow_migrate`` will now get passed
 without custom attributes, methods or managers. Make sure your ``allow_migrate``
 methods are only referring to fields or other items in ``model._meta``.
 
+Behavior of ``LocMemCache`` regarding pickle errors
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+An inconsistency existed in previous versions of Django regarding how pickle
+errors are handled by different cache backends.
+``django.core.cache.backends.locmem.LocMemCache`` used to fail silently when
+such an error occurs, which is inconsistent with other backends and leads to
+cache-specific errors. This has been fixed in Django 1.7, see
+`Ticket #21200`_ for more details.
+
+.. _Ticket #21200: https://code.djangoproject.com/ticket/21200
+
 Passing ``None`` to ``Manager.db_manager()``
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 

tests/cache/tests.py

@@ -48,6 +48,11 @@ class C:
         return 24
 
 
+class Unpickable(object):
+    def __getstate__(self):
+        raise pickle.PickleError()
+
+
 @override_settings(CACHES={
     'default': {
         'BACKEND': 'django.core.cache.backends.dummy.DummyCache',
@@ -847,6 +852,16 @@ class BaseCacheTests(object):
         self.assertEqual(get_cache_data.content, content.encode('utf-8'))
         self.assertEqual(get_cache_data.cookies, response.cookies)
 
+    def test_add_fail_on_pickleerror(self):
+         "See https://code.djangoproject.com/ticket/21200"
+         with self.assertRaises(pickle.PickleError):
+             cache.add('unpickable', Unpickable())
+
+    def test_set_fail_on_pickleerror(self):
+        "See https://code.djangoproject.com/ticket/21200"
+        with self.assertRaises(pickle.PickleError):
+            cache.set('unpickable', Unpickable())
+
 
 @override_settings(CACHES=caches_setting_for_tests(
     BACKEND='django.core.cache.backends.db.DatabaseCache',