diff -r cadcc8c20860 -r febe88a6f7f7 mercurial/debugcommands.py
--- a/mercurial/debugcommands.py	Wed Feb 12 10:53:24 2020 +0100
+++ b/mercurial/debugcommands.py	Tue Feb 18 18:32:55 2020 +0100
@@ -2109,7 +2109,10 @@
     if opts['dump_new']:
         unfi = repo.unfiltered()
         cl = unfi.changelog
-        data = nodemap.persistent_data(cl.index)
+        if util.safehasattr(cl.index, "nodemap_data_all"):
+            data = cl.index.nodemap_data_all()
+        else:
+            data = nodemap.persistent_data(cl.index)
         ui.write(data)
     elif opts['dump_disk']:
         unfi = repo.unfiltered()