Issue #11647: allow contextmanager objects to be used as decorators as described in the docs. Initial patch by Ysj Ray.
diff --git a/Lib/contextlib.py b/Lib/contextlib.py
index 4633cff..e90fc41 100644
--- a/Lib/contextlib.py
+++ b/Lib/contextlib.py
@@ -9,10 +9,23 @@
class ContextDecorator(object):
"A base class or mixin that enables context managers to work as decorators."
+
+ def _recreate_cm(self):
+ """Return a recreated instance of self.
+
+ Allows otherwise one-shot context managers like
+ _GeneratorContextManager to support use as
+ decorators via implicit recreation.
+
+ Note: this is a private interface just for _GCM in 3.2 but will be
+ renamed and documented for third party use in 3.3
+ """
+ return self
+
def __call__(self, func):
@wraps(func)
def inner(*args, **kwds):
- with self:
+ with self._recreate_cm():
return func(*args, **kwds)
return inner
@@ -20,8 +33,15 @@
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_cm(self):
+ # _GCM instances are one-shot context managers, so the
+ # CM must be recreated each time a decorated function is
+ # called
+ return self.__class__(self.func, *self.args, **self.kwds)
def __enter__(self):
try:
@@ -92,7 +112,7 @@
"""
@wraps(func)
def helper(*args, **kwds):
- return _GeneratorContextManager(func(*args, **kwds))
+ return _GeneratorContextManager(func, *args, **kwds)
return helper
diff --git a/Lib/test/test_contextlib.py b/Lib/test/test_contextlib.py
index d6bb5b8..6e38305 100644
--- a/Lib/test/test_contextlib.py
+++ b/Lib/test/test_contextlib.py
@@ -350,13 +350,13 @@
def test_contextmanager_as_decorator(self):
- state = []
@contextmanager
def woohoo(y):
state.append(y)
yield
state.append(999)
+ state = []
@woohoo(1)
def test(x):
self.assertEqual(state, [1])
@@ -364,6 +364,11 @@
test('something')
self.assertEqual(state, [1, 'something', 999])
+ # Issue #11647: Ensure the decorated function is 'reusable'
+ state = []
+ test('something else')
+ self.assertEqual(state, [1, 'something else', 999])
+
# This is needed to make the test actually run under regrtest.py!
def test_main():
diff --git a/Lib/test/test_with.py b/Lib/test/test_with.py
index a9d374b..e8cc8c0 100644
--- a/Lib/test/test_with.py
+++ b/Lib/test/test_with.py
@@ -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