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	Tue Mar 29 16:30:57 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)
 
diff -r 4fde67eddfae Lib/contextlib.py
--- a/Lib/contextlib.py	Mon Mar 28 17:08:36 2011 +0800
+++ b/Lib/contextlib.py	Tue Mar 29 16:30:57 2011 +0800
@@ -3,6 +3,7 @@
 import sys
 from functools import wraps
 from warnings import warn
+import copy
 
 __all__ = ["contextmanager", "closing", "ContextDecorator"]
 
@@ -20,10 +21,13 @@
 class _GeneratorContextManager(ContextDecorator):
     """Helper for @contextmanager decorator."""
 
-    def __init__(self, gen):
-        self.gen = gen
+    def __init__(self, func, *args, **kwds):
+        self.gen = None
+        self.func, self.args, self.kwds = func, args, kwds
 
     def __enter__(self):
+        if self.gen is None:
+            self.gen = self.func(*self.args, **self.kwds)
         try:
             return next(self.gen)
         except StopIteration:
@@ -61,6 +65,13 @@
                 if sys.exc_info()[1] is not value:
                     raise
 
+    def __call__(self, func):
+        @wraps(func)
+        def inner(*args, **kwds):
+            with copy.copy(self):
+                return func(*args, **kwds)
+        return inner
+
 
 def contextmanager(func):
     """@contextmanager decorator.
@@ -92,7 +103,7 @@
     """
     @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	Tue Mar 29 16:30:57 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	Tue Mar 29 16:30:57 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