diff -r c0d96bceadc2 -r 0d05915b688d mercurial/transaction.py
--- a/mercurial/transaction.py	Thu Apr 17 16:54:15 2014 -0400
+++ b/mercurial/transaction.py	Thu Apr 17 17:04:59 2014 -0400
@@ -86,6 +86,8 @@
         self.backupmap = {}
         self.journal = journal
         self._queue = []
+        # a dict of arguments to be passed to hooks
+        self.hookargs = {}
 
         self.backupjournal = "%s.backupfiles" % journal
         self.file = opener.open(self.journal, "w")