diff -r 4085c9fafb8e -r 38982de2b4eb mercurial/scmutil.py
--- a/mercurial/scmutil.py	Wed Apr 10 15:05:06 2013 -0700
+++ b/mercurial/scmutil.py	Wed Apr 10 15:08:25 2013 -0700
@@ -890,3 +890,9 @@
             del obj.__dict__[self.name]
         except KeyError:
             raise AttributeError(self.name)
+
+def finddirs(path):
+    pos = path.rfind('/')
+    while pos != -1:
+        yield path[:pos]
+        pos = path.rfind('/', 0, pos)