diff -r e2139e071b5c -r 083438d6f403 mercurial/debugcommands.py
--- a/mercurial/debugcommands.py	Mon Dec 14 16:15:01 2020 +0530
+++ b/mercurial/debugcommands.py	Wed Dec 16 12:39:15 2020 +0530
@@ -3933,7 +3933,7 @@
       * `--no-changelog --no-manifest --no-filelogs`: skip all filelog optimisation
     """
     return upgrade.upgraderepo(
-        ui, repo, run=run, optimize=optimize, backup=backup, **opts
+        ui, repo, run=run, optimize=set(optimize), backup=backup, **opts
     )