Fixed #599 -- locmem cache now uses deepcopy() to prevent aliasing. Thanks, Hugo

git-svn-id: http://code.djangoproject.com/svn/django/trunk@821 bcc190cf-cafb-0310-a4f2-bffc1f526a37

django/core/cache.py

@@ -72,7 +72,6 @@ class InvalidCacheBackendError(Exception):
 ################################
 
 class _Cache:
-
     def __init__(self, params):
         timeout = params.get('timeout', 300)
         try:
@@ -132,8 +131,7 @@ except ImportError:
     _MemcachedCache = None
 else:
     class _MemcachedCache(_Cache):
-        """Memcached cache backend."""
-
+        "Memcached cache backend."
         def __init__(self, server, params):
             _Cache.__init__(self, params)
             self._cache = memcache.Client([server])
@@ -161,8 +159,7 @@ else:
 import time
 
 class _SimpleCache(_Cache):
-    """Simple single-process in-memory cache"""
-
+    "Simple single-process in-memory cache."
     def __init__(self, host, params):
         _Cache.__init__(self, params)
         self._cache = {}
@@ -230,11 +227,11 @@ try:
     import cPickle as pickle
 except ImportError:
     import pickle
+import copy
 from django.utils.synch import RWLock
 
 class _LocMemCache(_SimpleCache):
-    """Thread-safe in-memory cache"""
-    
+    "Thread-safe in-memory cache."
     def __init__(self, host, params):
         _SimpleCache.__init__(self, host, params)
         self._lock = RWLock()
@@ -250,7 +247,7 @@ class _LocMemCache(_SimpleCache):
             elif exp < now:
                 should_delete = True
             else:
-                return self._cache[key]
+                return copy.deepcopy(self._cache[key])
         finally:
             self._lock.reader_leaves()
         if should_delete:
@@ -284,8 +281,7 @@ import os
 import urllib
 
 class _FileCache(_SimpleCache):
-    """File-based cache"""
-    
+    "File-based cache."
     def __init__(self, dir, params):
         self._dir = dir
         if not os.path.exists(self._dir):
@@ -366,8 +362,7 @@ from django.core.db import db, DatabaseError
 from datetime import datetime
 
 class _DBCache(_Cache):
-    """SQL cache backend"""
-    
+    "SQL cache backend."
     def __init__(self, table, params):
         _Cache.__init__(self, params)
         self._table = table

django/middleware/cache.py

@@ -1,4 +1,3 @@
-import copy
 from django.conf import settings
 from django.core.cache import cache
 from django.utils.cache import get_cache_key, learn_cache_key, patch_response_headers
@@ -49,7 +48,7 @@ class CacheMiddleware:
             return None # No cache information available, need to rebuild.
 
         request._cache_update_cache = False
-        return copy.copy(response)
+        return response
 
     def process_response(self, request, response):
         "Sets the cache, if needed."