diff --git a/tests/bundles/test-revlog-diff-relative-to-nullrev.sh b/tests/bundles/test-revlog-diff-relative-to-nullrev.sh
--- a/tests/bundles/test-revlog-diff-relative-to-nullrev.sh
+++ b/tests/bundles/test-revlog-diff-relative-to-nullrev.sh
@@ -1,9 +1,22 @@
 #!/bin/bash
 #
 # Make sure to patch mercurial to create the delta against nullrev
+#
+# # Parent  cdb85d0512b81031d4a7b30d6a5ddbe69ef1a876
+#
+# diff --git a/mercurial/revlogutils/deltas.py b/mercurial/revlogutils/deltas.py
+# --- a/mercurial/revlogutils/deltas.py
+# +++ b/mercurial/revlogutils/deltas.py
+# @@ -1117,7 +1117,10 @@ class deltacomputer:
+#                  candidaterevs = next(groups)
+#
 #          if deltainfo is None:
-#-             deltainfo = self._fullsnapshotinfo(fh, revinfo, target_rev)
-#+             deltainfo = self._builddeltainfo(revinfo, nullrev, fh)
+# -            deltainfo = self._fullsnapshotinfo(fh, revinfo, target_rev)
+# +            if revlog._generaldelta:
+# +                deltainfo = self._builddeltainfo(revinfo, nullrev, fh)
+# +            else:
+# +                deltainfo = self._fullsnapshotinfo(fh, revinfo, target_rev)
+
 
 cd "`dirname \"$0\"`"
 export HGRCPATH=