diff -r 7740d5102760 -r c407513a44a3 mercurial/upgrade_utils/actions.py
--- a/mercurial/upgrade_utils/actions.py	Sun Dec 06 20:38:01 2020 -0500
+++ b/mercurial/upgrade_utils/actions.py	Tue Dec 01 22:37:34 2020 +0100
@@ -554,6 +554,15 @@
     return newactions
 
 
+class UpgradeOperation(object):
+    """represent the work to be done during an upgrade"""
+
+    def __init__(self, requirements, actions, revlogs_to_process):
+        self.requirements = requirements
+        self.actions = actions
+        self.revlogs_to_process = revlogs_to_process
+
+
 ###  Code checking if a repository can got through the upgrade process at all. #