- implement armin's awesome metaclass adaptor, can drop the refs to MetaBase.

1 files changed, 17 insertions, 2 deletions

diff --git a/lib/sqlalchemy/util/compat.py b/lib/sqlalchemy/util/compat.py
index 3bbce5dde..fea22873c 100644
--- a/lib/sqlalchemy/util/compat.py
+++ b/lib/sqlalchemy/util/compat.py
@@ -209,6 +209,21 @@ else:
 
 
 def with_metaclass(meta, *bases):
-    """Create a base class with a metaclass."""
+    """Create a base class with a metaclass.
+
+    Drops the middle class upon creation.
+
+    Source: http://lucumr.pocoo.org/2013/5/21/porting-to-python-3-redux/
+
+    """
+
+    class metaclass(meta):
+        __call__ = type.__call__
+        __init__ = type.__init__
+        def __new__(cls, name, this_bases, d):
+            if this_bases is None:
+                return type.__new__(cls, name, (), d)
+            return meta(name, bases, d)
+    return metaclass('temporary_class', None, {})
+
 
-    return meta("MetaBase", bases, {})