Added savepoint protection to get_or_create() to avoid problems on PostgreSQL.

Fixed #7402.

Also made savepoint handling easier to use when wrapped around calls that might
commit a transaction. This is tested by the get_or_create tests.


git-svn-id: http://code.djangoproject.com/svn/django/trunk@8315 bcc190cf-cafb-0310-a4f2-bffc1f526a37

django/db/models/query.py

@@ -326,9 +326,12 @@ class QuerySet(object):
                 params = dict([(k, v) for k, v in kwargs.items() if '__' not in k])
                 params.update(defaults)
                 obj = self.model(**params)
+                sid = transaction.savepoint()
                 obj.save()
+                transaction.savepoint_commit(sid)
                 return obj, True
             except IntegrityError, e:
+                transaction.savepoint_rollback(sid)
                 return self.get(**kwargs), False
 
     def latest(self, field_name=None):