--- a/mercurial/dirstate.py	Fri Feb 11 22:24:10 2011 +0800
+++ b/mercurial/dirstate.py	Fri Dec 24 15:23:01 2010 +0100
@@ -80,7 +80,9 @@
     @propertycache
     def _pl(self):
         try:
-            st = self._opener("dirstate").read(40)
+            fp = self._opener("dirstate")
+            st = fp.read(40)
+            fp.close()
             l = len(st)
             if l == 40:
                 return st[:20], st[20:40]