From 14939faef613bd42ff2550deea37a894f38647d1 Mon Sep 17 00:00:00 2001
From: Matthew Tretter <m@tthewwithanm.com>
Date: Sat, 13 Jul 2013 17:13:58 -0400
Subject: [PATCH] Don't mutate __dict__

---
 imagekit/specs/__init__.py | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/imagekit/specs/__init__.py b/imagekit/specs/__init__.py
index 18f4958..bc33124 100644
--- a/imagekit/specs/__init__.py
+++ b/imagekit/specs/__init__.py
@@ -1,3 +1,4 @@
+from copy import copy
 from django.conf import settings
 from django.db.models.fields.files import ImageFieldFile
 from ..cachefiles.backends import get_default_cachefile_backend
@@ -108,7 +109,7 @@ class ImageSpec(BaseImageSpec):
         self._source = value
 
     def __getstate__(self):
-        state = self.__dict__
+        state = copy(self.__dict__)
 
         # Unpickled ImageFieldFiles won't work (they're missing a storage
         # object). Since they're such a common use case, we special case them.