diff -r 4fde67eddfae Doc/library/contextlib.rst
--- a/Doc/library/contextlib.rst	Mon Mar 28 17:08:36 2011 +0800
+++ b/Doc/library/contextlib.rst	Wed Mar 30 21:15:51 2011 +0800
@@ -60,6 +60,10 @@
    .. versionchanged:: 3.2
       Use of :class:`ContextDecorator`.
 
+   .. versionchanged:: 3.3
+      The function decorated by context manager which is created by contextmanager
+      is reusable.
+
 
 .. function:: closing(thing)
 
@@ -157,6 +161,10 @@
 
    .. versionadded:: 3.2
 
+   .. note::
+      If you want the decorated function to be reusable, the context manager
+      itself should be reusable, too.
+
 
 .. seealso::
 
diff -r 4fde67eddfae Lib/contextlib.py
--- a/Lib/contextlib.py	Mon Mar 28 17:08:36 2011 +0800
+++ b/Lib/contextlib.py	Wed Mar 30 21:15:51 2011 +0800
@@ -9,10 +9,18 @@
 
 class ContextDecorator(object):
     "A base class or mixin that enables context managers to work as decorators."
+
+    def _recreate(self):
+        """
+        Return a recreated instance of self used in the decorated function, in
+        order to make the decorated function reusable.
+        """
+        return self
+
     def __call__(self, func):
         @wraps(func)
         def inner(*args, **kwds):
-            with self:
+            with self._recreate():
                 return func(*args, **kwds)
         return inner
 
@@ -20,8 +28,12 @@
 class _GeneratorContextManager(ContextDecorator):
     """Helper for @contextmanager decorator."""
 
-    def __init__(self, gen):
-        self.gen = gen
+    def __init__(self, func, *args, **kwds):
+        self.gen = func(*args, **kwds)
+        self.func, self.args, self.kwds = func, args, kwds
+
+    def _recreate(self):
+        return self.__class__(self.func, *self.args, **self.kwds)
 
     def __enter__(self):
         try:
@@ -92,7 +104,7 @@
     """
     @wraps(func)
     def helper(*args, **kwds):
-        return _GeneratorContextManager(func(*args, **kwds))
+        return _GeneratorContextManager(func, *args, **kwds)
     return helper
 
 
diff -r 4fde67eddfae Lib/test/test_contextlib.py
--- a/Lib/test/test_contextlib.py	Mon Mar 28 17:08:36 2011 +0800
+++ b/Lib/test/test_contextlib.py	Wed Mar 30 21:15:51 2011 +0800
@@ -357,13 +357,20 @@
             yield
             state.append(999)
 
+        asserted_state = [1]
         @woohoo(1)
         def test(x):
-            self.assertEqual(state, [1])
+            self.assertEqual(state, asserted_state)
             state.append(x)
         test('something')
         self.assertEqual(state, [1, 'something', 999])
 
+        # Test if the decorated function is 'reusable'
+        asserted_state = [1, 'something', 999, 1]
+        test('something else')
+        self.assertEqual(state, [1, 'something', 999, 1, 'something else',
+            999])
+
 
 # This is needed to make the test actually run under regrtest.py!
 def test_main():
diff -r 4fde67eddfae Lib/test/test_with.py
--- a/Lib/test/test_with.py	Mon Mar 28 17:08:36 2011 +0800
+++ b/Lib/test/test_with.py	Wed Mar 30 21:15:51 2011 +0800
@@ -14,8 +14,8 @@
 
 
 class MockContextManager(_GeneratorContextManager):
-    def __init__(self, gen):
-        _GeneratorContextManager.__init__(self, gen)
+    def __init__(self, func, *args, **kwds):
+        super().__init__(func, *args, **kwds)
         self.enter_called = False
         self.exit_called = False
         self.exit_args = None
@@ -33,7 +33,7 @@
 
 def mock_contextmanager(func):
     def helper(*args, **kwds):
-        return MockContextManager(func(*args, **kwds))
+        return MockContextManager(func, *args, **kwds)
     return helper