[Python-checkins] bpo-33786: Fix asynchronous generators to handle GeneratorExit in athrow() (GH-7467)
Yury Selivanov
webhook-mailer at python.org
Thu Jun 7 20:31:29 EDT 2018
https://github.com/python/cpython/commit/52698c7ad9eae9feb35839fde17a7d1da8036a9b
commit: 52698c7ad9eae9feb35839fde17a7d1da8036a9b
branch: master
author: Yury Selivanov <yury at magic.io>
committer: GitHub <noreply at github.com>
date: 2018-06-07T20:31:26-04:00
summary:
bpo-33786: Fix asynchronous generators to handle GeneratorExit in athrow() (GH-7467)
files:
A Misc/NEWS.d/next/Core and Builtins/2018-06-06-23-24-40.bpo-33786.lBvT8z.rst
M Lib/contextlib.py
M Lib/test/test_asyncgen.py
M Lib/test/test_contextlib_async.py
M Objects/genobject.c
diff --git a/Lib/contextlib.py b/Lib/contextlib.py
index 1a58b509f67c..c06ec73f489d 100644
--- a/Lib/contextlib.py
+++ b/Lib/contextlib.py
@@ -187,7 +187,7 @@ class _AsyncGeneratorContextManager(_GeneratorContextManagerBase,
# in this implementation
try:
await self.gen.athrow(typ, value, traceback)
- raise RuntimeError("generator didn't stop after throw()")
+ raise RuntimeError("generator didn't stop after athrow()")
except StopAsyncIteration as exc:
return exc is not value
except RuntimeError as exc:
diff --git a/Lib/test/test_asyncgen.py b/Lib/test/test_asyncgen.py
index 8dc76ce5c9a1..9d60cb0e7e8f 100644
--- a/Lib/test/test_asyncgen.py
+++ b/Lib/test/test_asyncgen.py
@@ -108,6 +108,31 @@ def sync_iterate(g):
res.append(str(type(ex)))
return res
+ def async_iterate(g):
+ res = []
+ while True:
+ an = g.__anext__()
+ try:
+ while True:
+ try:
+ an.__next__()
+ except StopIteration as ex:
+ if ex.args:
+ res.append(ex.args[0])
+ break
+ else:
+ res.append('EMPTY StopIteration')
+ break
+ except StopAsyncIteration:
+ raise
+ except Exception as ex:
+ res.append(str(type(ex)))
+ break
+ except StopAsyncIteration:
+ res.append('STOP')
+ break
+ return res
+
def async_iterate(g):
res = []
while True:
@@ -297,6 +322,37 @@ def test_async_gen_exception_10(self):
"non-None value .* async generator"):
gen().__anext__().send(100)
+ def test_async_gen_exception_11(self):
+ def sync_gen():
+ yield 10
+ yield 20
+
+ def sync_gen_wrapper():
+ yield 1
+ sg = sync_gen()
+ sg.send(None)
+ try:
+ sg.throw(GeneratorExit())
+ except GeneratorExit:
+ yield 2
+ yield 3
+
+ async def async_gen():
+ yield 10
+ yield 20
+
+ async def async_gen_wrapper():
+ yield 1
+ asg = async_gen()
+ await asg.asend(None)
+ try:
+ await asg.athrow(GeneratorExit())
+ except GeneratorExit:
+ yield 2
+ yield 3
+
+ self.compare_generators(sync_gen_wrapper(), async_gen_wrapper())
+
def test_async_gen_api_01(self):
async def gen():
yield 123
diff --git a/Lib/test/test_contextlib_async.py b/Lib/test/test_contextlib_async.py
index 355955f9ab85..39dcd9b364e5 100644
--- a/Lib/test/test_contextlib_async.py
+++ b/Lib/test/test_contextlib_async.py
@@ -36,6 +36,28 @@ class DefaultEnter(AbstractAsyncContextManager):
async with manager as context:
self.assertIs(manager, context)
+ @_async_test
+ async def test_async_gen_propagates_generator_exit(self):
+ # A regression test for https://bugs.python.org/issue33786.
+
+ @asynccontextmanager
+ async def ctx():
+ yield
+
+ async def gen():
+ async with ctx():
+ yield 11
+
+ ret = []
+ exc = ValueError(22)
+ with self.assertRaises(ValueError):
+ async with ctx():
+ async for val in gen():
+ ret.append(val)
+ raise exc
+
+ self.assertEqual(ret, [11])
+
def test_exit_is_abstract(self):
class MissingAexit(AbstractAsyncContextManager):
pass
diff --git a/Misc/NEWS.d/next/Core and Builtins/2018-06-06-23-24-40.bpo-33786.lBvT8z.rst b/Misc/NEWS.d/next/Core and Builtins/2018-06-06-23-24-40.bpo-33786.lBvT8z.rst
new file mode 100644
index 000000000000..57deefe339b5
--- /dev/null
+++ b/Misc/NEWS.d/next/Core and Builtins/2018-06-06-23-24-40.bpo-33786.lBvT8z.rst
@@ -0,0 +1 @@
+Fix asynchronous generators to handle GeneratorExit in athrow() correctly
diff --git a/Objects/genobject.c b/Objects/genobject.c
index 9f593382f56a..e55cfd21c69c 100644
--- a/Objects/genobject.c
+++ b/Objects/genobject.c
@@ -1876,21 +1876,20 @@ async_gen_athrow_send(PyAsyncGenAThrow *o, PyObject *arg)
return NULL;
check_error:
- if (PyErr_ExceptionMatches(PyExc_StopAsyncIteration)) {
+ if (PyErr_ExceptionMatches(PyExc_StopAsyncIteration) ||
+ PyErr_ExceptionMatches(PyExc_GeneratorExit))
+ {
o->agt_state = AWAITABLE_STATE_CLOSED;
if (o->agt_args == NULL) {
/* when aclose() is called we don't want to propagate
- StopAsyncIteration; just raise StopIteration, signalling
- that 'aclose()' is done. */
+ StopAsyncIteration or GeneratorExit; just raise
+ StopIteration, signalling that this 'aclose()' await
+ is done.
+ */
PyErr_Clear();
PyErr_SetNone(PyExc_StopIteration);
}
}
- else if (PyErr_ExceptionMatches(PyExc_GeneratorExit)) {
- o->agt_state = AWAITABLE_STATE_CLOSED;
- PyErr_Clear(); /* ignore these errors */
- PyErr_SetNone(PyExc_StopIteration);
- }
return NULL;
}
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