From b9ef96e73cf2f2613eb6ca96038ef8c4271ac116 Mon Sep 17 00:00:00 2001
From: Nick Bruun <nick@bruun.co>
Date: Thu, 15 Aug 2013 20:59:58 +0200
Subject: [PATCH 1/2] Regression test and patch for ticket #20924.

---
 django/utils/functional.py                 |  8 ++++++++
 tests/utils_tests/test_simplelazyobject.py | 13 +++++++++++++
 2 files changed, 21 insertions(+)

diff --git a/django/utils/functional.py b/django/utils/functional.py
index d5d52205d7..465de283e5 100644
--- a/django/utils/functional.py
+++ b/django/utils/functional.py
@@ -270,6 +270,14 @@ class LazyObject(object):
     def __delitem__(self, key):
         del self[key]
 
+    @new_method_proxy
+    def __len__(self):
+        return len(self)
+
+    @new_method_proxy
+    def __contains__(self, key):
+        return key in self
+
 
 # Workaround for http://bugs.python.org/issue12370
 _super = super
diff --git a/tests/utils_tests/test_simplelazyobject.py b/tests/utils_tests/test_simplelazyobject.py
index 7b681d9290..f16b5e4da1 100644
--- a/tests/utils_tests/test_simplelazyobject.py
+++ b/tests/utils_tests/test_simplelazyobject.py
@@ -136,6 +136,9 @@ class TestUtilsSimpleLazyObject(TestCase):
         self.assertEqual(lazydict['one'], 1)
         lazydict['one'] = -1
         self.assertEqual(lazydict['one'], -1)
+        self.assertTrue('one' in lazydict)
+        self.assertFalse('two' in lazydict)
+        self.assertEqual(len(lazydict), 1)
         del lazydict['one']
         with self.assertRaises(KeyError):
             lazydict['one']
@@ -183,3 +186,13 @@ class TestUtilsSimpleLazyObject(TestCase):
 
             # This would fail with "TypeError: expected string or Unicode object, NoneType found".
             pickled = cPickle.dumps(x)
+
+    def test_list_set(self):
+        lazy_list = SimpleLazyObject(lambda: [1, 2, 3, 4, 5])
+        lazy_set = SimpleLazyObject(lambda: set([1, 2, 3, 4]))
+        self.assertTrue(1 in lazy_list)
+        self.assertTrue(1 in lazy_set)
+        self.assertFalse(6 in lazy_list)
+        self.assertFalse(6 in lazy_set)
+        self.assertEqual(len(lazy_list), 5)
+        self.assertEqual(len(lazy_set), 4)

From 7a698c05b56d7d5e267241dc71c16c403efd2965 Mon Sep 17 00:00:00 2001
From: Nick Bruun <nick@bruun.co>
Date: Sun, 18 Aug 2013 15:58:55 +0200
Subject: [PATCH 2/2] Update LazyObject method proxy declarations to simpler
 form.

---
 django/utils/functional.py | 9 ++-------
 1 file changed, 2 insertions(+), 7 deletions(-)

diff --git a/django/utils/functional.py b/django/utils/functional.py
index 465de283e5..7336572b35 100644
--- a/django/utils/functional.py
+++ b/django/utils/functional.py
@@ -270,13 +270,8 @@ class LazyObject(object):
     def __delitem__(self, key):
         del self[key]
 
-    @new_method_proxy
-    def __len__(self):
-        return len(self)
-
-    @new_method_proxy
-    def __contains__(self, key):
-        return key in self
+    __len__ = new_method_proxy(len)
+    __contains__ = new_method_proxy(operator.contains)
 
 
 # Workaround for http://bugs.python.org/issue12370