Issue #6470: Drop UNC prefix in FixTk.py
Patch by Christop Gohlke and Amaury Forgeot d'Arc.
diff --git a/Lib/lib-tk/FixTk.py b/Lib/lib-tk/FixTk.py
index 0d0966c..49960c7 100644
--- a/Lib/lib-tk/FixTk.py
+++ b/Lib/lib-tk/FixTk.py
@@ -42,6 +42,8 @@
         # Ignore leading \\?\
         if s.startswith("\\\\?\\"):
             s = s[4:]
+        if s.startswith("UNC"):
+            s = "\\" + s[3:]
         return s
 
 prefix = os.path.join(sys.prefix,"tcl")
diff --git a/Lib/test/test_tcl.py b/Lib/test/test_tcl.py
index 7057979..1b3c1cc 100644
--- a/Lib/test/test_tcl.py
+++ b/Lib/test/test_tcl.py
@@ -127,6 +127,31 @@
         tcl = self.interp
         self.assertRaises(TclError,tcl.eval,'package require DNE')
 
+    def testLoadWithUNC(self):
+        import sys
+        if sys.platform != 'win32':
+            return
+
+        # Build a UNC path from the regular path.
+        # Something like
+        #   \\%COMPUTERNAME%\c$\python27\python.exe
+
+        fullname = os.path.abspath(sys.executable)
+        if fullname[1] != ':':
+            return
+        unc_name = r'\\%s\%s$\%s' % (os.environ['COMPUTERNAME'],
+                                    fullname[0],
+                                    fullname[3:])
+
+        with test_support.EnvironmentVarGuard() as env:
+            env.unset("TCL_LIBRARY")
+            f = os.popen('%s -c "import Tkinter; print Tkinter"' % (unc_name,))
+
+        self.assert_('Tkinter.py' in f.read())
+        # exit code must be zero
+        self.assertEqual(f.close(), None)
+
+
 
 def test_main():
     test_support.run_unittest(TclTest, TkinterTest)
diff --git a/Misc/NEWS b/Misc/NEWS
index 3a5a449..0af2157 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -46,6 +46,8 @@
 Library
 -------
 
+- Issue #6470: Drop UNC prefix in FixTk.
+
 - Issue #5610: feedparser no longer eats extra characters at the end of
   a body part if the body part ends with a \r\n.