https://github.com/python/cpython/commit/925dc7fb1d0db85dc137afa4cd14211bf0d... commit: 925dc7fb1d0db85dc137afa4cd14211bf0d67414 branch: master author: Nathaniel J. Smith <njs@pobox.com> committer: GitHub <noreply@github.com> date: 2020-02-13T00:15:38-08:00 summary: bpo-39606: allow closing async generators that are already closed (GH-18475) The fix for [bpo-39386](https://bugs.python.org/issue39386) attempted to make it so you couldn't reuse a agen.aclose() coroutine object. It accidentally also prevented you from calling aclose() at all on an async generator that was already closed or exhausted. This commit fixes it so we're only blocking the actually illegal cases, while allowing the legal cases. The new tests failed before this patch. Also confirmed that this fixes the test failures we were seeing in Trio with Python dev builds: https://github.com/python-trio/trio/pull/1396 https://bugs.python.org/issue39606 files: A Misc/NEWS.d/next/Core and Builtins/2020-02-11-23-59-07.bpo-39606.a72Sxc.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 24b20bec2b2d1..fb6321d2264f3 100644 --- a/Lib/test/test_asyncgen.py +++ b/Lib/test/test_asyncgen.py @@ -1128,7 +1128,7 @@ def exception_handler(loop, context): self.assertEqual([], messages) - def test_async_gen_await_anext_twice(self): + def test_async_gen_await_same_anext_coro_twice(self): async def async_iterate(): yield 1 yield 2 @@ -1147,7 +1147,7 @@ def test_async_gen_await_anext_twice(self): self.loop.run_until_complete(run()) - def test_async_gen_await_aclose_twice(self): + def test_async_gen_await_same_aclose_coro_twice(self): async def async_iterate(): yield 1 yield 2 @@ -1164,6 +1164,32 @@ def test_async_gen_await_aclose_twice(self): self.loop.run_until_complete(run()) + def test_async_gen_aclose_twice_with_different_coros(self): + # Regression test for https://bugs.python.org/issue39606 + async def async_iterate(): + yield 1 + yield 2 + + async def run(): + it = async_iterate() + await it.aclose() + await it.aclose() + + self.loop.run_until_complete(run()) + + def test_async_gen_aclose_after_exhaustion(self): + # Regression test for https://bugs.python.org/issue39606 + async def async_iterate(): + yield 1 + yield 2 + + async def run(): + it = async_iterate() + async for _ in it: + pass + await it.aclose() + + self.loop.run_until_complete(run()) if __name__ == "__main__": unittest.main() diff --git a/Misc/NEWS.d/next/Core and Builtins/2020-02-11-23-59-07.bpo-39606.a72Sxc.rst b/Misc/NEWS.d/next/Core and Builtins/2020-02-11-23-59-07.bpo-39606.a72Sxc.rst new file mode 100644 index 0000000000000..b7cbe4e91f59c --- /dev/null +++ b/Misc/NEWS.d/next/Core and Builtins/2020-02-11-23-59-07.bpo-39606.a72Sxc.rst @@ -0,0 +1,2 @@ +Fix regression caused by fix for bpo-39386, that prevented calling +``aclose`` on an async generator that had already been closed or exhausted. diff --git a/Objects/genobject.c b/Objects/genobject.c index 576d6856c7f30..0efd57de7a5a3 100644 --- a/Objects/genobject.c +++ b/Objects/genobject.c @@ -1797,16 +1797,22 @@ async_gen_athrow_send(PyAsyncGenAThrow *o, PyObject *arg) PyFrameObject *f = gen->gi_frame; PyObject *retval; - if (f == NULL || f->f_stacktop == NULL || - o->agt_state == AWAITABLE_STATE_CLOSED) { + if (o->agt_state == AWAITABLE_STATE_CLOSED) { PyErr_SetString( PyExc_RuntimeError, "cannot reuse already awaited aclose()/athrow()"); return NULL; } + if (f == NULL || f->f_stacktop == NULL) { + o->agt_state = AWAITABLE_STATE_CLOSED; + PyErr_SetNone(PyExc_StopIteration); + return NULL; + } + if (o->agt_state == AWAITABLE_STATE_INIT) { if (o->agt_gen->ag_running_async) { + o->agt_state = AWAITABLE_STATE_CLOSED; if (o->agt_args == NULL) { PyErr_SetString( PyExc_RuntimeError, @@ -1878,7 +1884,6 @@ async_gen_athrow_send(PyAsyncGenAThrow *o, PyObject *arg) /* aclose() mode */ if (retval) { if (_PyAsyncGenWrappedValue_CheckExact(retval)) { - o->agt_gen->ag_running_async = 0; Py_DECREF(retval); goto yield_close; } @@ -1893,16 +1898,17 @@ async_gen_athrow_send(PyAsyncGenAThrow *o, PyObject *arg) yield_close: o->agt_gen->ag_running_async = 0; + o->agt_state = AWAITABLE_STATE_CLOSED; PyErr_SetString( PyExc_RuntimeError, ASYNC_GEN_IGNORED_EXIT_MSG); return NULL; check_error: o->agt_gen->ag_running_async = 0; + o->agt_state = AWAITABLE_STATE_CLOSED; 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 or GeneratorExit; just raise @@ -1936,6 +1942,7 @@ async_gen_athrow_throw(PyAsyncGenAThrow *o, PyObject *args) /* aclose() mode */ if (retval && _PyAsyncGenWrappedValue_CheckExact(retval)) { o->agt_gen->ag_running_async = 0; + o->agt_state = AWAITABLE_STATE_CLOSED; Py_DECREF(retval); PyErr_SetString(PyExc_RuntimeError, ASYNC_GEN_IGNORED_EXIT_MSG); return NULL;