Ticket #18541: LocMemlocking.diff

django/core/cache/backends/locmem.py

@@ -69 +69 @@
     def set(self, key, value, timeout=None, version=None):
         key = self.make_key(key, version=version)
         self.validate_key(key)
+        try:
+            pickled = pickle.dumps(value, pickle.HIGHEST_PROTOCOL)
+        except pickle.PickleError:
+            return
         with self._lock.writer():
-            try:
-                pickled = pickle.dumps(value, pickle.HIGHEST_PROTOCOL)
-                self._set(key, pickled, timeout)
-            except pickle.PickleError:
-                pass
+            self._set(key, pickled, timeout)
 
     def incr(self, key, delta=1, version=None):
         value = self.get(key, version=version)

tests/regressiontests/cache/tests.py

@@ -42 +42 @@
         return 24
 
 
+class PicklingSideEffect(object):
+    def __getstate__(self):
+        self.cache.get('foo')
+        return {}
+
+
 class DummyCacheTests(unittest.TestCase):
     # The Dummy cache backend doesn't really behave like a test backend,
     # so it has different test requirements.
@@ -919 +925 @@
         self.assertEqual(mirror_cache.get('value1'), 42)
         self.assertEqual(other_cache.get('value1'), None)
 
+    def test_locking_on_pickle(self):
+
+        cache = self.cache
+
+        bad_obj = PicklingSideEffect()
+        bad_obj.cache = cache
+        cache.set('bar', bad_obj)
+
     def test_incr_decr_timeout(self):
         """incr/decr does not modify expiry time (matches memcached behavior)"""
         key = 'value'