--- a/mercurial/error.py	Wed Oct 21 19:00:16 2020 -0700
+++ b/mercurial/error.py	Tue Oct 06 22:36:15 2020 -0700
@@ -181,6 +181,13 @@
             return pycompat.sysstr(self.__bytes__())
 
 
+class InputError(Abort):
+    """Indicates that the user made an error in their input.
+
+    Examples: Invalid command, invalid flags, invalid revision.
+    """
+
+
 class HookLoadError(Abort):
     """raised when loading a hook fails, aborting an operation