diff -r 673f0fdc1046 -r 0298a07f64d9 mercurial/node.py
--- a/mercurial/node.py	Mon Nov 07 18:57:54 2016 -0800
+++ b/mercurial/node.py	Thu Nov 10 02:17:22 2016 -0800
@@ -17,6 +17,12 @@
 nullid = b"\0" * 20
 nullhex = hex(nullid)
 
+# Phony node value to stand-in for new files in some uses of
+# manifests.
+newnodeid = '!' * 20
+
+wdirnodes = set((newnodeid,))
+
 # pseudo identifiers for working directory
 # (they are experimental, so don't add too many dependencies on them)
 wdirrev = 0x7fffffff