diff -r ac7a3da0dbb6 -r 78f0bb37f52d mercurial/upgrade.py
--- a/mercurial/upgrade.py	Thu Sep 17 18:49:57 2020 -0700
+++ b/mercurial/upgrade.py	Thu Jun 25 13:16:55 2020 +0530
@@ -108,6 +108,7 @@
         requirements.SIDEDATA_REQUIREMENT,
         requirements.COPIESSDC_REQUIREMENT,
         requirements.NODEMAP_REQUIREMENT,
+        requirements.SHARESAFE_REQUIREMENT,
     }
     for name in compression.compengines:
         engine = compression.compengines[name]