diff --git a/Doc/whatsnew/3.11.rst b/Doc/whatsnew/3.11.rst index cc88c4166ec1af..be1423b9f44b39 100644 --- a/Doc/whatsnew/3.11.rst +++ b/Doc/whatsnew/3.11.rst @@ -76,6 +76,12 @@ Other Language Changes ====================== +* A :exc:`TypeError` is now raised instead of an :exc:`AttributeError` in + :keyword:`with` and :keyword:`async with` statements for objects which do not + support the :term:`context manager` or :term:`asynchronous context manager` + protocols correspondingly. + (Contributed by Serhiy Storchaka in :issue:`12022`.) + New Modules =========== diff --git a/Lib/test/test_contextlib.py b/Lib/test/test_contextlib.py index 453ef6c9f0832f..dbc3f5fbe2b273 100644 --- a/Lib/test/test_contextlib.py +++ b/Lib/test/test_contextlib.py @@ -491,7 +491,7 @@ def __unter__(self): def __exit__(self, *exc): pass - with self.assertRaises(AttributeError): + with self.assertRaisesRegex(TypeError, 'the context manager'): with mycontext(): pass @@ -503,7 +503,7 @@ def __enter__(self): def __uxit__(self, *exc): pass - with self.assertRaises(AttributeError): + with self.assertRaisesRegex(TypeError, 'the context manager.*__exit__'): with mycontext(): pass diff --git a/Lib/test/test_coroutines.py b/Lib/test/test_coroutines.py index a6a199e323c5f9..9b83244b5006d0 100644 --- a/Lib/test/test_coroutines.py +++ b/Lib/test/test_coroutines.py @@ -1212,7 +1212,7 @@ async def foo(): async with CM(): body_executed = True - with self.assertRaisesRegex(AttributeError, '__aexit__'): + with self.assertRaisesRegex(TypeError, 'asynchronous context manager.*__aexit__'): run_async(foo()) self.assertIs(body_executed, False) @@ -1228,7 +1228,7 @@ async def foo(): async with CM(): body_executed = True - with self.assertRaisesRegex(AttributeError, '__aenter__'): + with self.assertRaisesRegex(TypeError, 'asynchronous context manager'): run_async(foo()) self.assertIs(body_executed, False) @@ -1243,7 +1243,7 @@ async def foo(): async with CM(): body_executed = True - with self.assertRaisesRegex(AttributeError, '__aenter__'): + with self.assertRaisesRegex(TypeError, 'asynchronous context manager'): run_async(foo()) self.assertIs(body_executed, False) diff --git a/Lib/test/test_with.py b/Lib/test/test_with.py index f21bf65fed8499..07522bda6a5583 100644 --- a/Lib/test/test_with.py +++ b/Lib/test/test_with.py @@ -117,7 +117,7 @@ def __exit__(self, type, value, traceback): def fooLacksEnter(): foo = LacksEnter() with foo: pass - self.assertRaisesRegex(AttributeError, '__enter__', fooLacksEnter) + self.assertRaisesRegex(TypeError, 'the context manager', fooLacksEnter) def testEnterAttributeError2(self): class LacksEnterAndExit(object): @@ -126,7 +126,7 @@ class LacksEnterAndExit(object): def fooLacksEnterAndExit(): foo = LacksEnterAndExit() with foo: pass - self.assertRaisesRegex(AttributeError, '__enter__', fooLacksEnterAndExit) + self.assertRaisesRegex(TypeError, 'the context manager', fooLacksEnterAndExit) def testExitAttributeError(self): class LacksExit(object): @@ -136,7 +136,7 @@ def __enter__(self): def fooLacksExit(): foo = LacksExit() with foo: pass - self.assertRaisesRegex(AttributeError, '__exit__', fooLacksExit) + self.assertRaisesRegex(TypeError, 'the context manager.*__exit__', fooLacksExit) def assertRaisesSyntaxError(self, codestr): def shouldRaiseSyntaxError(s): diff --git a/Misc/NEWS.d/next/Core and Builtins/2021-06-20-10-53-21.bpo-12022.SW240M.rst b/Misc/NEWS.d/next/Core and Builtins/2021-06-20-10-53-21.bpo-12022.SW240M.rst new file mode 100644 index 00000000000000..98c42283169d8e --- /dev/null +++ b/Misc/NEWS.d/next/Core and Builtins/2021-06-20-10-53-21.bpo-12022.SW240M.rst @@ -0,0 +1,4 @@ +A :exc:`TypeError` is now raised instead of an :exc:`AttributeError` in +:keyword:`with` and :keyword:`async with` statements for objects which do +not support the :term:`context manager` or :term:`asynchronous context +manager` protocols correspondingly. diff --git a/Python/ceval.c b/Python/ceval.c index 3f961f60c081c2..2ae36b3d28edda 100644 --- a/Python/ceval.c +++ b/Python/ceval.c @@ -82,7 +82,6 @@ static void format_exc_check_arg(PyThreadState *, PyObject *, const char *, PyOb static void format_exc_unbound(PyThreadState *tstate, PyCodeObject *co, int oparg); static PyObject * unicode_concatenate(PyThreadState *, PyObject *, PyObject *, PyFrameObject *, const _Py_CODEUNIT *); -static PyObject * special_lookup(PyThreadState *, PyObject *, _Py_Identifier *); static int check_args_iterable(PyThreadState *, PyObject *func, PyObject *vararg); static void format_kwargs_error(PyThreadState *, PyObject *func, PyObject *kwargs); static void format_awaitable_error(PyThreadState *, PyTypeObject *, int, int); @@ -3844,13 +3843,26 @@ _PyEval_EvalFrameDefault(PyThreadState *tstate, PyFrameObject *f, int throwflag) _Py_IDENTIFIER(__aenter__); _Py_IDENTIFIER(__aexit__); PyObject *mgr = TOP(); - PyObject *enter = special_lookup(tstate, mgr, &PyId___aenter__); PyObject *res; + PyObject *enter = _PyObject_LookupSpecial(mgr, &PyId___aenter__); if (enter == NULL) { + if (!_PyErr_Occurred(tstate)) { + _PyErr_Format(tstate, PyExc_TypeError, + "'%.200s' object does not support the " + "asynchronous context manager protocol", + Py_TYPE(mgr)->tp_name); + } goto error; } - PyObject *exit = special_lookup(tstate, mgr, &PyId___aexit__); + PyObject *exit = _PyObject_LookupSpecial(mgr, &PyId___aexit__); if (exit == NULL) { + if (!_PyErr_Occurred(tstate)) { + _PyErr_Format(tstate, PyExc_TypeError, + "'%.200s' object does not support the " + "asynchronous context manager protocol " + "(missed __aexit__ method)", + Py_TYPE(mgr)->tp_name); + } Py_DECREF(enter); goto error; } @@ -3869,13 +3881,26 @@ _PyEval_EvalFrameDefault(PyThreadState *tstate, PyFrameObject *f, int throwflag) _Py_IDENTIFIER(__enter__); _Py_IDENTIFIER(__exit__); PyObject *mgr = TOP(); - PyObject *enter = special_lookup(tstate, mgr, &PyId___enter__); PyObject *res; + PyObject *enter = _PyObject_LookupSpecial(mgr, &PyId___enter__); if (enter == NULL) { + if (!_PyErr_Occurred(tstate)) { + _PyErr_Format(tstate, PyExc_TypeError, + "'%.200s' object does not support the " + "context manager protocol", + Py_TYPE(mgr)->tp_name); + } goto error; } - PyObject *exit = special_lookup(tstate, mgr, &PyId___exit__); + PyObject *exit = _PyObject_LookupSpecial(mgr, &PyId___exit__); if (exit == NULL) { + if (!_PyErr_Occurred(tstate)) { + _PyErr_Format(tstate, PyExc_TypeError, + "'%.200s' object does not support the " + "context manager protocol " + "(missed __exit__ method)", + Py_TYPE(mgr)->tp_name); + } Py_DECREF(enter); goto error; } @@ -5110,19 +5135,6 @@ PyEval_EvalCodeEx(PyObject *_co, PyObject *globals, PyObject *locals, } -static PyObject * -special_lookup(PyThreadState *tstate, PyObject *o, _Py_Identifier *id) -{ - PyObject *res; - res = _PyObject_LookupSpecial(o, id); - if (res == NULL && !_PyErr_Occurred(tstate)) { - _PyErr_SetObject(tstate, PyExc_AttributeError, _PyUnicode_FromId(id)); - return NULL; - } - return res; -} - - /* Logic for the raise statement (too complicated for inlining). This *consumes* a reference count to each of its arguments. */ static int