--- a/tests/drawdag.py	Mon Apr 19 20:38:52 2021 -0400
+++ b/tests/drawdag.py	Mon Mar 29 01:52:06 2021 +0200
@@ -86,7 +86,6 @@
 import itertools
 import re
 
-from mercurial.node import nullid
 from mercurial.i18n import _
 from mercurial import (
     context,
@@ -299,7 +298,7 @@
         self._added = added
         self._parents = parentctxs
         while len(self._parents) < 2:
-            self._parents.append(repo[nullid])
+            self._parents.append(repo[repo.nullid])
 
     def filectx(self, key):
         return simplefilectx(key, self._added[key])
@@ -388,7 +387,7 @@
         content = content.replace(br'\n', b'\n').replace(br'\1', b'\1')
         files[name][path] = content
 
-    committed = {None: nullid}  # {name: node}
+    committed = {None: repo.nullid}  # {name: node}
 
     # for leaf nodes, try to find existing nodes in repo
     for name, parents in edges.items():