[PATCH STABLE] dirstate: make sure rootdir ends with directory separator (issue4557)

[Yuya Nishihara]

# HG changeset patch
# User Yuya Nishihara <yuya at tcha.org>
# Date 1425568462 -32400
#      Fri Mar 06 00:14:22 2015 +0900
# Branch stable
# Node ID ad75672575f0cfdba49815a3222f052a3f9de53d
# Parent  ac41aa4a66ab21210fc538e9fb51c405a341b69e
dirstate: make sure rootdir ends with directory separator (issue4557)

ntpath.join() of Python 2.7.9 does not work as expected if root is a UNC path
to top of share.

This patch doesn't take care of os.altsep, '/' on Windows, because root should
be normalized by realpath().

diff --git a/mercurial/dirstate.py b/mercurial/dirstate.py
--- a/mercurial/dirstate.py
+++ b/mercurial/dirstate.py
@@ -38,7 +38,12 @@ class dirstate(object):
         self._opener = opener
         self._validate = validate
         self._root = root
-        self._rootdir = os.path.join(root, '')
+        # ntpath.join(root, '') of Python 2.7.9 does not add sep if root is
+        # UNC path pointing to root share (issue4557)
+        if root.endswith(os.sep):
+            self._rootdir = root
+        else:
+            self._rootdir = root + os.sep
         self._dirty = False
         self._dirtypl = False
         self._lastnormaltime = 0