Fixed MultiValueDict's copy implementation to be consistant with all other copies.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@14366 bcc190cf-cafb-0310-a4f2-bffc1f526a37

django/utils/datastructures.py

@@ -1,6 +1,6 @@
 from types import GeneratorType
 
-from django.utils.copycompat import deepcopy
+from django.utils.copycompat import copy, deepcopy
 
 
 class MergeDict(object):
@@ -263,7 +263,10 @@ class MultiValueDict(dict):
         super(MultiValueDict, self).__setitem__(key, [value])
 
     def __copy__(self):
-        return self.__class__(super(MultiValueDict, self).items())
+        return self.__class__([
+            (k, v[:])
+            for k, v in self.lists()
+        ])
 
     def __deepcopy__(self, memo=None):
         import django.utils.copycompat as copy
@@ -361,8 +364,8 @@ class MultiValueDict(dict):
             yield self[key]
 
     def copy(self):
-        """Returns a copy of this object."""
-        return self.__deepcopy__()
+        """Returns a shallow copy of this object."""
+        return copy(self)
 
     def update(self, *args, **kwargs):
         """
@@ -491,4 +494,3 @@ class DictWrapper(dict):
         if use_func:
             return self.func(value)
         return value
-

tests/regressiontests/utils/datastructures.py

@@ -4,6 +4,7 @@ Tests for stuff in django.utils.datastructures.
 import pickle
 import unittest
 
+from django.utils.copycompat import copy
 from django.utils.datastructures import *
 
 
@@ -211,6 +212,26 @@ class MultiValueDictTests(DatastructuresTestCase):
         self.assertEquals(list(d.itervalues()),
                           ['Developer', 'Simon', 'Willison'])
 
+    def test_copy(self):
+        for copy_func in [copy, lambda d: d.copy()]:
+            d1 = MultiValueDict({
+                "developers": ["Carl", "Fred"]
+            })
+            self.assertEqual(d1["developers"], "Fred")
+            d2 = copy_func(d1)
+            d2.update({"developers": "Groucho"})
+            self.assertEqual(d2["developers"], "Groucho")
+            self.assertEqual(d1["developers"], "Fred")
+
+            d1 = MultiValueDict({
+                "key": [[]]
+            })
+            self.assertEqual(d1["key"], [])
+            d2 = copy_func(d1)
+            d2["key"].append("Penguin")
+            self.assertEqual(d1["key"], ["Penguin"])
+            self.assertEqual(d2["key"], ["Penguin"])
+
 
 class DotExpandedDictTests(DatastructuresTestCase):