https://github.com/python/cpython/commit/a68f2f0578bbf812fa2264d0e0bb388340d... commit: a68f2f0578bbf812fa2264d0e0bb388340d6e230 branch: master author: Serhiy Storchaka <storchaka@gmail.com> committer: GitHub <noreply@github.com> date: 2018-04-03T01:41:38+03:00 summary: bpo-29922: Improve error messages in 'async with' (GH-6352) when __aenter__() or __aexit__() return non-awaitable object. files: A Misc/NEWS.d/next/Core and Builtins/2018-04-03-00-30-25.bpo-29922.CdLuMl.rst M Lib/test/test_coroutines.py M Python/ceval.c diff --git a/Lib/test/test_coroutines.py b/Lib/test/test_coroutines.py index fe26199f95af..9ad7ff9564bc 100644 --- a/Lib/test/test_coroutines.py +++ b/Lib/test/test_coroutines.py @@ -1255,7 +1255,9 @@ def __aexit__(self, *e): pass with self.assertRaisesRegex( - TypeError, "object int can't be used in 'await' expression"): + TypeError, + "'async with' received an object from __aenter__ " + "that does not implement __await__: int"): # it's important that __aexit__ wasn't called run_async(foo()) @@ -1275,7 +1277,9 @@ def __aexit__(self, *e): run_async(foo()) except TypeError as exc: self.assertRegex( - exc.args[0], "object int can't be used in 'await' expression") + exc.args[0], + "'async with' received an object from __aexit__ " + "that does not implement __await__: int") self.assertTrue(exc.__context__ is not None) self.assertTrue(isinstance(exc.__context__, ZeroDivisionError)) else: @@ -1299,8 +1303,9 @@ def __aexit__(self, *e): with self.assertRaisesRegex( - TypeError, "object int can't be used in 'await' expression"): - + TypeError, + "'async with' received an object from __aexit__ " + "that does not implement __await__: int"): run_async(foo()) self.assertEqual(CNT, 1) diff --git a/Misc/NEWS.d/next/Core and Builtins/2018-04-03-00-30-25.bpo-29922.CdLuMl.rst b/Misc/NEWS.d/next/Core and Builtins/2018-04-03-00-30-25.bpo-29922.CdLuMl.rst new file mode 100644 index 000000000000..d8c144e59d6c --- /dev/null +++ b/Misc/NEWS.d/next/Core and Builtins/2018-04-03-00-30-25.bpo-29922.CdLuMl.rst @@ -0,0 +1,2 @@ +Improved error messages in 'async with' when ``__aenter__()`` or +``__aexit__()`` return non-awaitable object. diff --git a/Python/ceval.c b/Python/ceval.c index d18a284e9f9d..da83e41f5ddd 100644 --- a/Python/ceval.c +++ b/Python/ceval.c @@ -69,6 +69,7 @@ static PyObject * unicode_concatenate(PyObject *, PyObject *, static PyObject * special_lookup(PyObject *, _Py_Identifier *); static int check_args_iterable(PyObject *func, PyObject *vararg); static void format_kwargs_mapping_error(PyObject *func, PyObject *kwargs); +static void format_awaitable_error(PyTypeObject *, int); #define NAME_ERROR_MSG \ "name '%.200s' is not defined" @@ -1736,6 +1737,11 @@ _PyEval_EvalFrameDefault(PyFrameObject *f, int throwflag) PyObject *iterable = TOP(); PyObject *iter = _PyCoro_GetAwaitableIter(iterable); + if (iter == NULL) { + format_awaitable_error(Py_TYPE(iterable), + _Py_OPCODE(next_instr[-2])); + } + Py_DECREF(iterable); if (iter != NULL && PyCoro_CheckExact(iter)) { @@ -4985,6 +4991,25 @@ format_exc_unbound(PyCodeObject *co, int oparg) } } +static void +format_awaitable_error(PyTypeObject *type, int prevopcode) +{ + if (type->tp_as_async == NULL || type->tp_as_async->am_await == NULL) { + if (prevopcode == BEFORE_ASYNC_WITH) { + PyErr_Format(PyExc_TypeError, + "'async with' received an object from __aenter__ " + "that does not implement __await__: %.100s", + type->tp_name); + } + else if (prevopcode == WITH_CLEANUP_START) { + PyErr_Format(PyExc_TypeError, + "'async with' received an object from __aexit__ " + "that does not implement __await__: %.100s", + type->tp_name); + } + } +} + static PyObject * unicode_concatenate(PyObject *v, PyObject *w, PyFrameObject *f, const _Py_CODEUNIT *next_instr)