--- a/mercurial/repair.py	Wed Mar 03 12:35:29 2021 +0100
+++ b/mercurial/repair.py	Wed Mar 03 12:37:13 2021 +0100
@@ -443,7 +443,7 @@
     """
     repo = repo.unfiltered()
 
-    if b'fncache' not in repo.requirements:
+    if requirements.FNCACHE_REQUIREMENT not in repo.requirements:
         ui.warn(
             _(
                 b'(not rebuilding fncache because repository does not '