diff --git a/hgext/journal.py b/hgext/journal.py
--- a/hgext/journal.py
+++ b/hgext/journal.py
@@ -226,7 +226,7 @@
 
     def __bytes__(self):
         """bytes representation for storage"""
-        time = ' '.join(map(pycompat.bytestr, self.timestamp))
+        time = ' '.join([pycompat.bytestr(a) for a in self.timestamp])
         oldhashes = ','.join([node.hex(hash) for hash in self.oldhashes])
         newhashes = ','.join([node.hex(hash) for hash in self.newhashes])
         return '\n'.join((
@@ -273,7 +273,7 @@
     @property
     def command(self):
         commandstr = ' '.join(
-            map(procutil.shellquote, journalstorage._currentcommand))
+            [procutil.shellquote(a) for a in journalstorage._currentcommand])
         if '\n' in commandstr:
             # truncate multi-line commands
             commandstr = commandstr.partition('\n')[0] + ' ...'