diff --git a/mercurial/extensions.py b/mercurial/extensions.py
--- a/mercurial/extensions.py
+++ b/mercurial/extensions.py
@@ -399,6 +399,21 @@
         raise AttributeError(r"type '%s' has no property '%s'" % (
             cls, propname))
 
+class wrappedfunction(object):
+  '''context manager for temporarily wrapping a function'''
+
+  def __init__(self, container, funcname, wrapper):
+    assert callable(wrapper)
+    self._container = container
+    self._funcname = funcname
+    self._wrapper = wrapper
+
+  def __enter__(self):
+    wrapfunction(self._container, self._funcname, self._wrapper)
+
+  def __exit__(self, exctype, excvalue, traceback):
+    unwrapfunction(self._container, self._funcname)
+
 def wrapfunction(container, funcname, wrapper):
     '''Wrap the function named funcname in container
 
diff --git a/tests/test-extensions-wrapfunction.py b/tests/test-extensions-wrapfunction.py
--- a/tests/test-extensions-wrapfunction.py
+++ b/tests/test-extensions-wrapfunction.py
@@ -37,3 +37,16 @@
 batchwrap(wrappers + [wrappers[0]])
 batchunwrap([(wrappers[i] if i >= 0 else None)
              for i in [3, None, 0, 4, 0, 2, 1, None]])
+
+wrap0 = extensions.wrappedfunction(dummy, 'getstack', wrappers[0])
+wrap1 = extensions.wrappedfunction(dummy, 'getstack', wrappers[1])
+
+# Use them in a different order from how they were created to check that
+# the wrapping happens in __enter__, not in __init__
+print('context manager', dummy.getstack())
+with wrap1:
+  print('context manager', dummy.getstack())
+  with wrap0:
+    print('context manager', dummy.getstack())
+  print('context manager', dummy.getstack())
+print('context manager', dummy.getstack())
diff --git a/tests/test-extensions-wrapfunction.py.out b/tests/test-extensions-wrapfunction.py.out
--- a/tests/test-extensions-wrapfunction.py.out
+++ b/tests/test-extensions-wrapfunction.py.out
@@ -12,3 +12,8 @@
 unwrap 2: 2: [1, 'orig']
 unwrap 1: 1: ['orig']
 unwrap -: -: IndexError
+context manager ['orig']
+context manager [1, 'orig']
+context manager [0, 1, 'orig']
+context manager [1, 'orig']
+context manager ['orig']