- Added a new SessionExtension hook called after_attach().

This is called at the point of attachment for objects
via add(), add_all(), delete(), and merge().

2 files changed, 7 insertions, 0 deletions

diff --git a/lib/sqlalchemy/orm/interfaces.py b/lib/sqlalchemy/orm/interfaces.py
index 4cfc9462a..96a6e340c 100644
--- a/lib/sqlalchemy/orm/interfaces.py
+++ b/lib/sqlalchemy/orm/interfaces.py
@@ -301,6 +301,11 @@ class SessionExtension(object):
         engine level transaction is begun on a connection.
         """
 
+    def after_attach(self, session, instance):
+        """Execute after an instance is attached to a session.
+
+        This is called after an add, delete or merge.
+        """
 
 class MapperProperty(object):
     """Manage the relationship of a ``Mapper`` to a single class
diff --git a/lib/sqlalchemy/orm/session.py b/lib/sqlalchemy/orm/session.py
index b9f170733..380bc8622 100644
--- a/lib/sqlalchemy/orm/session.py
+++ b/lib/sqlalchemy/orm/session.py
@@ -1283,6 +1283,8 @@ class Session(object):
                                     state.session_id, self.hash_key))
         if state.session_id != self.hash_key:
             state.session_id = self.hash_key
+        if self.extension is not None:
+            self.extension.after_attach(self, state.obj())
 
     def __contains__(self, instance):
         """Return True if the instance is associated with this session.