diff -r b758351d191f -r cc9b7e14412b web/lib/django/db/models/fields/subclassing.py
--- a/web/lib/django/db/models/fields/subclassing.py	Wed May 19 17:43:59 2010 +0200
+++ b/web/lib/django/db/models/fields/subclassing.py	Tue May 25 02:43:45 2010 +0200
@@ -1,11 +1,77 @@
 """
-Convenience routines for creating non-trivial Field subclasses.
+Convenience routines for creating non-trivial Field subclasses, as well as
+backwards compatibility utilities.
 
 Add SubfieldBase as the __metaclass__ for your Field subclass, implement
 to_python() and the other necessary methods and everything will work seamlessly.
 """
 
-class SubfieldBase(type):
+from inspect import getargspec
+from warnings import warn
+
+def call_with_connection(func):
+    arg_names, varargs, varkwargs, defaults = getargspec(func)
+    updated = ('connection' in arg_names or varkwargs)
+    if not updated:
+        warn("A Field class whose %s method hasn't been updated to take a "
+            "`connection` argument." % func.__name__,
+            PendingDeprecationWarning, stacklevel=2)
+
+    def inner(*args, **kwargs):
+        if 'connection' not in kwargs:
+            from django.db import connection
+            kwargs['connection'] = connection
+            warn("%s has been called without providing a connection argument. " %
+                func.__name__, PendingDeprecationWarning,
+                stacklevel=1)
+        if updated:
+            return func(*args, **kwargs)
+        if 'connection' in kwargs:
+            del kwargs['connection']
+        return func(*args, **kwargs)
+    return inner
+
+def call_with_connection_and_prepared(func):
+    arg_names, varargs, varkwargs, defaults = getargspec(func)
+    updated = (
+        ('connection' in arg_names or varkwargs) and
+        ('prepared' in arg_names or varkwargs)
+    )
+    if not updated:
+        warn("A Field class whose %s method hasn't been updated to take "
+            "`connection` and `prepared` arguments." % func.__name__,
+            PendingDeprecationWarning, stacklevel=2)
+
+    def inner(*args, **kwargs):
+        if 'connection' not in kwargs:
+            from django.db import connection
+            kwargs['connection'] = connection
+            warn("%s has been called without providing a connection argument. " %
+                func.__name__, PendingDeprecationWarning,
+                stacklevel=1)
+        if updated:
+            return func(*args, **kwargs)
+        if 'connection' in kwargs:
+            del kwargs['connection']
+        if 'prepared' in kwargs:
+            del kwargs['prepared']
+        return func(*args, **kwargs)
+    return inner
+
+class LegacyConnection(type):
+    """
+    A metaclass to normalize arguments give to the get_db_prep_* and db_type
+    methods on fields.
+    """
+    def __new__(cls, names, bases, attrs):
+        new_cls = super(LegacyConnection, cls).__new__(cls, names, bases, attrs)
+        for attr in ('db_type', 'get_db_prep_save'):
+            setattr(new_cls, attr, call_with_connection(getattr(new_cls, attr)))
+        for attr in ('get_db_prep_lookup', 'get_db_prep_value'):
+            setattr(new_cls, attr, call_with_connection_and_prepared(getattr(new_cls, attr)))
+        return new_cls
+
+class SubfieldBase(LegacyConnection):
     """
     A metaclass for custom Field subclasses. This ensures the model's attribute
     has the descriptor protocol attached to it.
@@ -26,7 +92,7 @@
     def __get__(self, obj, type=None):
         if obj is None:
             raise AttributeError('Can only be accessed via an instance.')
-        return obj.__dict__[self.field.name]        
+        return obj.__dict__[self.field.name]
 
     def __set__(self, obj, value):
         obj.__dict__[self.field.name] = self.field.to_python(value)