mercurial/filelog.py

--- a/mercurial/filelog.py	Tue Dec 19 20:41:25 2017 +0800
+++ b/mercurial/filelog.py	Sun Jan 07 15:01:59 2018 -0500
@@ -43,6 +43,8 @@
     def __init__(self, opener, path):
         super(filelog, self).__init__(opener,
                         "/".join(("data", path + ".i")))
+        # full name of the user visible file, relative to the repository root
+        self.filename = path
 
     def read(self, node):
         t = self.revision(node)