From 2ad5421dad86bc95aabe5c77f6034ee6ca699992 Mon Sep 17 00:00:00 2001
From: Benjamin Peterson <benjamin@python.org>
Date: Sun, 31 Aug 2014 09:34:09 -0400
Subject: [PATCH] don't index outside of the path (closes #22312)

---
 Lib/ntpath.py           | 2 +-
 Lib/test/test_ntpath.py | 1 +
 Misc/NEWS               | 2 ++
 3 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/Lib/ntpath.py b/Lib/ntpath.py
index 228bbb3f52..fcaf21b6b7 100644
--- a/Lib/ntpath.py
+++ b/Lib/ntpath.py
@@ -113,7 +113,7 @@ def splitdrive(p):
     """
     if len(p) > 1:
         normp = p.replace(altsep, sep)
-        if (normp[0:2] == sep*2) and (normp[2] != sep):
+        if (normp[0:2] == sep*2) and (normp[2:3] != sep):
             # is a UNC path:
             # vvvvvvvvvvvvvvvvvvvv drive letter or UNC path
             # \\machine\mountpoint\directory\etc\...
diff --git a/Lib/test/test_ntpath.py b/Lib/test/test_ntpath.py
index 78af18c621..7b5f7bb28c 100644
--- a/Lib/test/test_ntpath.py
+++ b/Lib/test/test_ntpath.py
@@ -50,6 +50,7 @@ class TestNtpath(unittest.TestCase):
         # Issue #19911: UNC part containing U+0130
         self.assertEqual(ntpath.splitdrive(u'//conky/MOUNTPOÄ°NT/foo/bar'),
                          (u'//conky/MOUNTPOÄ°NT', '/foo/bar'))
+        self.assertEqual(ntpath.splitdrive("//"), ("", "//"))
 
     def test_splitunc(self):
         tester('ntpath.splitunc("c:\\foo\\bar")',
diff --git a/Misc/NEWS b/Misc/NEWS
index 5d800347f4..d139e7b9d6 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -19,6 +19,8 @@ Core and Builtins
 Library
 -------
 
+- Issue #22312: Fix ntpath.splitdrive IndexError.
+
 - Issue #22216: smtplib now resets its state more completely after a quit.  The
   most obvious consequence of the previous behavior was a STARTTLS failure
   during a connect/starttls/quit/connect/starttls sequence.
-- 
2.50.1