[Python-checkins] bpo-39386: Prevent double awaiting of async iterator (GH-18081)
Miss Islington (bot)
webhook-mailer at python.org
Mon Jan 20 18:06:45 EST 2020
https://github.com/python/cpython/commit/5cadd3fe3aead1b5bee1438dc03383d6739d4209
commit: 5cadd3fe3aead1b5bee1438dc03383d6739d4209
branch: 3.8
author: Miss Islington (bot) <31488909+miss-islington at users.noreply.github.com>
committer: GitHub <noreply at github.com>
date: 2020-01-20T15:06:40-08:00
summary:
bpo-39386: Prevent double awaiting of async iterator (GH-18081)
(cherry picked from commit a96e06db77dcbd3433d39761ddb4615d7d96284a)
Co-authored-by: Andrew Svetlov <andrew.svetlov at gmail.com>
files:
A Misc/NEWS.d/next/Core and Builtins/2020-01-20-21-40-57.bpo-39386.ULqD8t.rst
M Lib/test/test_asyncgen.py
M Objects/genobject.c
diff --git a/Lib/test/test_asyncgen.py b/Lib/test/test_asyncgen.py
index 58d8aee19adac..24b20bec2b2d1 100644
--- a/Lib/test/test_asyncgen.py
+++ b/Lib/test/test_asyncgen.py
@@ -1128,6 +1128,42 @@ def exception_handler(loop, context):
self.assertEqual([], messages)
+ def test_async_gen_await_anext_twice(self):
+ async def async_iterate():
+ yield 1
+ yield 2
+
+ async def run():
+ it = async_iterate()
+ nxt = it.__anext__()
+ await nxt
+ with self.assertRaisesRegex(
+ RuntimeError,
+ r"cannot reuse already awaited __anext__\(\)/asend\(\)"
+ ):
+ await nxt
+
+ await it.aclose() # prevent unfinished iterator warning
+
+ self.loop.run_until_complete(run())
+
+ def test_async_gen_await_aclose_twice(self):
+ async def async_iterate():
+ yield 1
+ yield 2
+
+ async def run():
+ it = async_iterate()
+ nxt = it.aclose()
+ await nxt
+ with self.assertRaisesRegex(
+ RuntimeError,
+ r"cannot reuse already awaited aclose\(\)/athrow\(\)"
+ ):
+ await nxt
+
+ self.loop.run_until_complete(run())
+
if __name__ == "__main__":
unittest.main()
diff --git a/Misc/NEWS.d/next/Core and Builtins/2020-01-20-21-40-57.bpo-39386.ULqD8t.rst b/Misc/NEWS.d/next/Core and Builtins/2020-01-20-21-40-57.bpo-39386.ULqD8t.rst
new file mode 100644
index 0000000000000..f24e1f4e8a183
--- /dev/null
+++ b/Misc/NEWS.d/next/Core and Builtins/2020-01-20-21-40-57.bpo-39386.ULqD8t.rst
@@ -0,0 +1 @@
+Prevent double awaiting of async iterator.
diff --git a/Objects/genobject.c b/Objects/genobject.c
index 5643553b708d1..72aa872c6b59f 100644
--- a/Objects/genobject.c
+++ b/Objects/genobject.c
@@ -1533,7 +1533,9 @@ async_gen_asend_send(PyAsyncGenASend *o, PyObject *arg)
PyObject *result;
if (o->ags_state == AWAITABLE_STATE_CLOSED) {
- PyErr_SetNone(PyExc_StopIteration);
+ PyErr_SetString(
+ PyExc_RuntimeError,
+ "cannot reuse already awaited __anext__()/asend()");
return NULL;
}
@@ -1576,7 +1578,9 @@ async_gen_asend_throw(PyAsyncGenASend *o, PyObject *args)
PyObject *result;
if (o->ags_state == AWAITABLE_STATE_CLOSED) {
- PyErr_SetNone(PyExc_StopIteration);
+ PyErr_SetString(
+ PyExc_RuntimeError,
+ "cannot reuse already awaited __anext__()/asend()");
return NULL;
}
@@ -1810,7 +1814,9 @@ async_gen_athrow_send(PyAsyncGenAThrow *o, PyObject *arg)
if (f == NULL || f->f_stacktop == NULL ||
o->agt_state == AWAITABLE_STATE_CLOSED) {
- PyErr_SetNone(PyExc_StopIteration);
+ PyErr_SetString(
+ PyExc_RuntimeError,
+ "cannot reuse already awaited aclose()/athrow()");
return NULL;
}
@@ -1932,7 +1938,9 @@ async_gen_athrow_throw(PyAsyncGenAThrow *o, PyObject *args)
PyObject *retval;
if (o->agt_state == AWAITABLE_STATE_CLOSED) {
- PyErr_SetNone(PyExc_StopIteration);
+ PyErr_SetString(
+ PyExc_RuntimeError,
+ "cannot reuse already awaited aclose()/athrow()");
return NULL;
}
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