--- a/mercurial/context.py	Tue Jun 16 22:13:19 2015 +0900
+++ b/mercurial/context.py	Tue Jun 16 23:03:36 2015 -0400
@@ -249,11 +249,18 @@
             return ''
 
     def sub(self, path):
+        '''return a subrepo for the stored revision of path, never wdir()'''
         return subrepo.subrepo(self, path)
 
     def nullsub(self, path, pctx):
         return subrepo.nullsubrepo(self, path, pctx)
 
+    def workingsub(self, path):
+        '''return a subrepo for the stored revision, or wdir if this is a wdir
+        context.
+        '''
+        return subrepo.subrepo(self, path, allowwdir=True)
+
     def match(self, pats=[], include=None, exclude=None, default='glob',
               listsubrepos=False, badfn=None):
         r = self._repo