- Fixed bug in Query involving order_by() in conjunction with

multiple aliases of the same class (will add tests in
[ticket:1218])
- Added a new extension sqlalchemy.ext.serializer.  Provides
Serializer/Deserializer "classes" which mirror Pickle/Unpickle,
as well as dumps() and loads().  This serializer implements
an "external object" pickler which keeps key context-sensitive
objects, including engines, sessions, metadata, Tables/Columns,
and mappers, outside of the pickle stream, and can later
restore the pickle using any engine/metadata/session provider.
This is used not for pickling regular object instances, which are
pickleable without any special logic, but for pickling expression
objects and full Query objects, such that all mapper/engine/session
dependencies can be restored at unpickle time.

1 files changed, 16 insertions, 1 deletions

diff --git a/lib/sqlalchemy/sql/expression.py b/lib/sqlalchemy/sql/expression.py
index 85f229ba0..5206dc5fa 100644
--- a/lib/sqlalchemy/sql/expression.py
+++ b/lib/sqlalchemy/sql/expression.py
@@ -1002,6 +1002,11 @@ class ClauseElement(Visitable):
             yield f
             f = getattr(f, '_is_clone_of', None)
 
+    def __getstate__(self):
+        d = self.__dict__.copy()
+        d.pop('_is_clone_of', None)
+        return d
+        
     def _get_from_objects(self, **modifiers):
         """Return objects represented in this ``ClauseElement`` that
         should be added to the ``FROM`` list of a query, when this
@@ -1959,7 +1964,17 @@ class _BindParamClause(ColumnElement):
 
         """
         return isinstance(other, _BindParamClause) and other.type.__class__ == self.type.__class__
-
+    
+    def __getstate__(self):
+        """execute a deferred value for serialization purposes."""
+        
+        d = self.__dict__.copy()
+        v = self.value
+        if callable(v):
+            v = v()
+        d['value'] = v
+        return d
+        
     def __repr__(self):
         return "_BindParamClause(%s, %s, type_=%s)" % (repr(self.key), repr(self.value), repr(self.type))