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):

django/db/transaction.py

@@ -105,6 +105,12 @@ def set_clean():
         dirty[thread_ident] = False
     else:
         raise TransactionManagementError("This code isn't under transaction management")
+    clean_savepoints()
+
+def clean_savepoints():
+    thread_ident = thread.get_ident()
+    if thread_ident in savepoint_state:
+        del savepoint_state[thread_ident]
 
 def is_managed():
     """
@@ -139,6 +145,7 @@ def commit_unless_managed():
     """
     if not is_managed():
         connection._commit()
+        clean_savepoints()
     else:
         set_dirty()
 
@@ -186,6 +193,7 @@ def savepoint_rollback(sid):
     Rolls back the most recent savepoint (if one exists). Does nothing if
     savepoints are not supported.
     """
+    if thread.get_ident() in savepoint_state:
         connection._savepoint_rollback(sid)
 
 def savepoint_commit(sid):
@@ -193,6 +201,7 @@ def savepoint_commit(sid):
     Commits the most recent savepoint (if one exists). Does nothing if
     savepoints are not supported.
     """
+    if thread.get_ident() in savepoint_state:
         connection._savepoint_commit(sid)
 
 ##############