Fix a problem with @contextmanager not detecting a broken generator
that yields after a throw(). Make @contextmanager not reraise
exceptions, but return a false value in that case instead. Add test
cases for both behaviors.
diff --git a/Lib/contextlib.py b/Lib/contextlib.py
index 0a5d608..282fc51 100644
--- a/Lib/contextlib.py
+++ b/Lib/contextlib.py
@@ -30,9 +30,12 @@
else:
try:
self.gen.throw(type, value, traceback)
- return True
+ raise RuntimeError("generator didn't stop after throw()")
except StopIteration:
return True
+ except:
+ if sys.exc_info()[1] is not value:
+ raise
def contextmanager(func):
diff --git a/Lib/test/test_contextlib.py b/Lib/test/test_contextlib.py
index f8db88c..7d7f8d2 100644
--- a/Lib/test/test_contextlib.py
+++ b/Lib/test/test_contextlib.py
@@ -45,6 +45,28 @@
self.fail("Expected ZeroDivisionError")
self.assertEqual(state, [1, 42, 999])
+ def test_contextmanager_no_reraise(self):
+ @contextmanager
+ def whee():
+ yield
+ ctx = whee().__context__()
+ ctx.__enter__()
+ # Calling __exit__ should not result in an exception
+ self.failIf(ctx.__exit__(TypeError, TypeError("foo"), None))
+
+ def test_contextmanager_trap_yield_after_throw(self):
+ @contextmanager
+ def whoo():
+ try:
+ yield
+ except:
+ yield
+ ctx = whoo().__context__()
+ ctx.__enter__()
+ self.assertRaises(
+ RuntimeError, ctx.__exit__, TypeError, TypeError("foo"), None
+ )
+
def test_contextmanager_except(self):
state = []
@contextmanager