[Python-checkins] bpo-29922: Improve error messages in 'async with' (GH-6352)
Miss Islington (bot)
webhook-mailer at python.org
Wed Apr 4 10:09:17 EDT 2018
https://github.com/python/cpython/commit/4fd6c27dc8ba7ca97aa70e1ab98729f2207bbe19
commit: 4fd6c27dc8ba7ca97aa70e1ab98729f2207bbe19
branch: 3.6
author: Miss Islington (bot) <31488909+miss-islington at users.noreply.github.com>
committer: GitHub <noreply at github.com>
date: 2018-04-04T07:09:14-07:00
summary:
bpo-29922: Improve error messages in 'async with' (GH-6352)
when __aenter__() or __aexit__() return non-awaitable object.
(cherry picked from commit a68f2f0578bbf812fa2264d0e0bb388340d6e230)
Co-authored-by: Serhiy Storchaka <storchaka at gmail.com>
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 41126b675b5c..769879f082c5 100644
--- a/Lib/test/test_coroutines.py
+++ b/Lib/test/test_coroutines.py
@@ -1229,7 +1229,9 @@ 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())
@@ -1249,7 +1251,9 @@ 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:
@@ -1273,8 +1277,9 @@ 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 9ad582b15c57..6252e89c9106 100644
--- a/Python/ceval.c
+++ b/Python/ceval.c
@@ -66,6 +66,7 @@ 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"
@@ -2040,6 +2041,11 @@ _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)) {
@@ -5403,6 +5409,25 @@ 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)
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