diff --git a/hgext/histedit.py b/hgext/histedit.py
--- a/hgext/histedit.py
+++ b/hgext/histedit.py
@@ -344,7 +344,7 @@
         fp.write('v1\n')
         fp.write('%s\n' % node.hex(self.parentctxnode))
         fp.write('%s\n' % node.hex(self.topmost))
-        fp.write('%s\n' % self.keep)
+        fp.write('%s\n' % 'True' if self.keep else 'False')
         fp.write('%d\n' % len(self.actions))
         for action in self.actions:
             fp.write('%s\n' % action.tostate())