Merge.
diff --git a/Lib/contextlib.py b/Lib/contextlib.py
index ead1155..f5232b6 100644
--- a/Lib/contextlib.py
+++ b/Lib/contextlib.py
@@ -225,32 +225,21 @@
return self
def __exit__(self, *exc_details):
- if not self._exit_callbacks:
- return
- # This looks complicated, but it is really just
- # setting up a chain of try-expect statements to ensure
- # that outer callbacks still get invoked even if an
- # inner one throws an exception
- def _invoke_next_callback(exc_details):
- # Callbacks are removed from the list in FIFO order
- # but the recursion means they're invoked in LIFO order
- cb = self._exit_callbacks.popleft()
- if not self._exit_callbacks:
- # Innermost callback is invoked directly
- return cb(*exc_details)
- # More callbacks left, so descend another level in the stack
+ # Callbacks are invoked in LIFO order to match the behaviour of
+ # nested context managers
+ suppressed_exc = False
+ while self._exit_callbacks:
+ cb = self._exit_callbacks.pop()
try:
- suppress_exc = _invoke_next_callback(exc_details)
- except:
- suppress_exc = cb(*sys.exc_info())
- # Check if this cb suppressed the inner exception
- if not suppress_exc:
- raise
- else:
- # Check if inner cb suppressed the original exception
- if suppress_exc:
+ if cb(*exc_details):
+ suppressed_exc = True
exc_details = (None, None, None)
- suppress_exc = cb(*exc_details) or suppress_exc
- return suppress_exc
- # Kick off the recursive chain
- return _invoke_next_callback(exc_details)
+ except:
+ new_exc_details = sys.exc_info()
+ if exc_details != (None, None, None):
+ # simulate the stack of exceptions by setting the context
+ new_exc_details[1].__context__ = exc_details[1]
+ if not self._exit_callbacks:
+ raise
+ exc_details = new_exc_details
+ return suppressed_exc
diff --git a/Lib/test/test_contextlib.py b/Lib/test/test_contextlib.py
index e5eed21..efa9dcb 100644
--- a/Lib/test/test_contextlib.py
+++ b/Lib/test/test_contextlib.py
@@ -572,6 +572,12 @@
stack.push(lambda *exc: 1/0)
stack.push(lambda *exc: {}[1])
+ def test_excessive_nesting(self):
+ # The original implementation would die with RecursionError here
+ with ExitStack() as stack:
+ for i in range(10000):
+ stack.callback(int)
+
def test_instance_bypass(self):
class Example(object): pass
cm = Example()
diff --git a/Misc/NEWS b/Misc/NEWS
index 0ae13d4..caeed46 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -7,11 +7,17 @@
*Release date: TBD*
+Library
+-------
+
+- Issue #14963: Convert contextlib.ExitStack.__exit__ to use an iterative
+ algorithm (Patch by Alon Horev)
+
Tests
-----
- Issue #14963 (partial): Add test cases for exception handling behaviour
- in contextlib.ContextStack (Initial patch by Alon Horev)
+ in contextlib.ExitStack (Initial patch by Alon Horev)
What's New in Python 3.3.0 Alpha 4?
===================================