--- a/mercurial/error.py	Wed Jul 13 10:39:33 2016 -0400
+++ b/mercurial/error.py	Wed Jul 13 16:16:18 2016 +0100
@@ -240,3 +240,6 @@
 
 class UnsupportedBundleSpecification(Exception):
     """error raised when a bundle specification is not supported."""
+
+class CorruptedState(Exception):
+    """error raised when a command is not able to read its state from file"""