- [feature] Calling rollback() within a

session.begin_nested() will now only expire
those objects that had net changes within the
scope of that transaction, that is objects which
were dirty or were modified on a flush.  This
allows the typical use case for begin_nested(),
that of altering a small subset of objects, to
leave in place the data from the larger enclosing
set of objects that weren't modified in
that sub-transaction.  [ticket:2452]
- inline the "register_newly_XYZ" functions to operate
upon collections to reduce method calls

1 files changed, 8 insertions, 7 deletions

diff --git a/lib/sqlalchemy/orm/unitofwork.py b/lib/sqlalchemy/orm/unitofwork.py
index 3523e7d06..bc3be8b41 100644
--- a/lib/sqlalchemy/orm/unitofwork.py
+++ b/lib/sqlalchemy/orm/unitofwork.py
@@ -339,13 +339,14 @@ class UOWTransaction(object):
         execute() method has succeeded and the transaction has been committed.
 
         """
-        for state, (isdelete, listonly) in self.states.iteritems():
-            if isdelete:
-                self.session._remove_newly_deleted(state)
-            else:
-                # if listonly:
-                #   debug... would like to see how many do this
-                self.session._register_newly_persistent(state)
+        states = set(self.states)
+        isdel = set(
+            s for (s, (isdelete, listonly)) in self.states.iteritems()
+            if isdelete
+        )
+        other = states.difference(isdel)
+        self.session._remove_newly_deleted(isdel)
+        self.session._register_newly_persistent(other)
 
 class IterateMappersMixin(object):
     def _mappers(self, uow):