Fixed #3810 -- In newforms, copy attribute dictionaries before modifying them

in place.


git-svn-id: http://code.djangoproject.com/svn/django/trunk@4894 bcc190cf-cafb-0310-a4f2-bffc1f526a37

django/newforms/widgets.py

@@ -24,7 +24,10 @@ class Widget(object):
     is_hidden = False          # Determines whether this corresponds to an <input type="hidden">.
 
     def __init__(self, attrs=None):
-        self.attrs = attrs or {}
+        if attrs is not None:
+            self.attrs = attrs.copy()
+        else:
+            self.attrs = {}
 
     def render(self, name, value, attrs=None):
         """