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