Fix contextlib.nested to cope with exit methods raising and handling exceptions
diff --git a/Lib/contextlib.py b/Lib/contextlib.py
index aa5335d..157b4cc 100644
--- a/Lib/contextlib.py
+++ b/Lib/contextlib.py
@@ -127,7 +127,10 @@
except:
exc = sys.exc_info()
if exc != (None, None, None):
- raise
+ # Don't rely on sys.exc_info() still containing
+ # the right information. Another exception may
+ # have been raised and caught by an exit method
+ raise exc[0], exc[1], exc[2]
@contextmanager
diff --git a/Lib/test/test_contextlib.py b/Lib/test/test_contextlib.py
index 97470c7..c23e428 100644
--- a/Lib/test/test_contextlib.py
+++ b/Lib/test/test_contextlib.py
@@ -146,6 +146,29 @@
else:
self.fail("Didn't raise ZeroDivisionError")
+ def test_nested_right_exception(self):
+ state = []
+ @contextmanager
+ def a():
+ yield 1
+ class b(object):
+ def __enter__(self):
+ return 2
+ def __exit__(self, *exc_info):
+ try:
+ raise Exception()
+ except:
+ pass
+ try:
+ with nested(a(), b()) as (x, y):
+ 1/0
+ except ZeroDivisionError:
+ self.assertEqual((x, y), (1, 2))
+ except Exception:
+ self.fail("Reraised wrong exception")
+ else:
+ self.fail("Didn't raise ZeroDivisionError")
+
def test_nested_b_swallows(self):
@contextmanager
def a():