diff -r 6a917075535a -r 968dd7e02ac5 mercurial/repository.py
--- a/mercurial/repository.py	Tue Oct 09 23:26:35 2018 +0200
+++ b/mercurial/repository.py	Wed Oct 10 00:21:02 2018 +0200
@@ -42,6 +42,7 @@
 CG_DELTAMODE_STD = b'default'
 CG_DELTAMODE_PREV = b'previous'
 CG_DELTAMODE_FULL = b'fulltext'
+CG_DELTAMODE_P1 = b'p1'
 
 class ipeerconnection(interfaceutil.Interface):
     """Represents a "connection" to a repository.