--- a/mercurial/shelve.py	Tue Mar 30 02:33:12 2021 +0200
+++ b/mercurial/shelve.py	Tue Mar 30 02:32:30 2021 +0200
@@ -534,7 +534,7 @@
     parent = parents[0]
     origbranch = wctx.branch()
 
-    if parent.node() != nullid:
+    if parent.rev() != nullrev:
         desc = b"changes to: %s" % parent.description().split(b'\n', 1)[0]
     else:
         desc = b'(changes in empty repository)'