--- a/web/lib/django/core/exceptions.py	Wed May 19 17:43:59 2010 +0200
+++ b/web/lib/django/core/exceptions.py	Tue May 25 02:43:45 2010 +0200
@@ -32,6 +32,51 @@
     """Some kind of problem with a model field."""
     pass
 
+NON_FIELD_ERRORS = '__all__'
 class ValidationError(Exception):
     """An error while validating data."""
-    pass
+    def __init__(self, message, code=None, params=None):
+        import operator
+        from django.utils.encoding import force_unicode
+        """
+        ValidationError can be passed any object that can be printed (usually
+        a string), a list of objects or a dictionary.
+        """
+        if isinstance(message, dict):
+            self.message_dict = message
+            # Reduce each list of messages into a single list.
+            message = reduce(operator.add, message.values())
+
+        if isinstance(message, list):
+            self.messages = [force_unicode(msg) for msg in message]
+        else:
+            self.code = code
+            self.params = params
+            message = force_unicode(message)
+            self.messages = [message]
+
+    def __str__(self):
+        # This is needed because, without a __str__(), printing an exception
+        # instance would result in this:
+        # AttributeError: ValidationError instance has no attribute 'args'
+        # See http://www.python.org/doc/current/tut/node10.html#handling
+        if hasattr(self, 'message_dict'):
+            return repr(self.message_dict)
+        return repr(self.messages)
+
+    def __repr__(self):
+        if hasattr(self, 'message_dict'):
+            return 'ValidationError(%s)' % repr(self.message_dict)
+        return 'ValidationError(%s)' % repr(self.messages)
+
+    def update_error_dict(self, error_dict):
+        if hasattr(self, 'message_dict'):
+            if error_dict:
+                for k, v in self.message_dict.items():
+                    error_dict.setdefault(k, []).extend(v)
+            else:
+                error_dict = self.message_dict
+        else:
+            error_dict[NON_FIELD_ERRORS] = self.messages
+        return error_dict
+