diff -r f923bdd7477d -r b5858e02e3ba mercurial/manifest.py
--- a/mercurial/manifest.py	Fri May 13 15:19:57 2022 +0200
+++ b/mercurial/manifest.py	Tue Apr 06 03:23:46 2021 +0200
@@ -1589,7 +1589,7 @@
         self._fulltextcache = manifestfulltextcache(cachesize)
 
         if tree:
-            assert self._treeondisk, b'opts is %r' % opts
+            assert self._treeondisk, (tree, b'opts is %r' % opts)
 
         radix = b'00manifest'
         if tree: