Issue #24400: Introduce a distinct type for 'async def' coroutines.
Summary of changes:
1. Coroutines now have a distinct, separate from generators
type at the C level: PyGen_Type, and a new typedef PyCoroObject.
PyCoroObject shares the initial segment of struct layout with
PyGenObject, making it possible to reuse existing generators
machinery. The new type is exposed as 'types.CoroutineType'.
As a consequence of having a new type, CO_GENERATOR flag is
no longer applied to coroutines.
2. Having a separate type for coroutines made it possible to add
an __await__ method to the type. Although it is not used by the
interpreter (see details on that below), it makes coroutines
naturally (without using __instancecheck__) conform to
collections.abc.Coroutine and collections.abc.Awaitable ABCs.
[The __instancecheck__ is still used for generator-based
coroutines, as we don't want to add __await__ for generators.]
3. Add new opcode: GET_YIELD_FROM_ITER. The opcode is needed to
allow passing native coroutines to the YIELD_FROM opcode.
Before this change, 'yield from o' expression was compiled to:
(o)
GET_ITER
LOAD_CONST
YIELD_FROM
Now, we use GET_YIELD_FROM_ITER instead of GET_ITER.
The reason for adding a new opcode is that GET_ITER is used
in some contexts (such as 'for .. in' loops) where passing
a coroutine object is invalid.
4. Add two new introspection functions to the inspec module:
getcoroutinestate(c) and getcoroutinelocals(c).
5. inspect.iscoroutine(o) is updated to test if 'o' is a native
coroutine object. Before this commit it used abc.Coroutine,
and it was requested to update inspect.isgenerator(o) to use
abc.Generator; it was decided, however, that inspect functions
should really be tailored for checking for native types.
6. sys.set_coroutine_wrapper(w) API is updated to work with only
native coroutines. Since types.coroutine decorator supports
any type of callables now, it would be confusing that it does
not work for all types of coroutines.
7. Exceptions logic in generators C implementation was updated
to raise clearer messages for coroutines:
Before: TypeError("generator raised StopIteration")
After: TypeError("coroutine raised StopIteration")
diff --git a/Objects/genobject.c b/Objects/genobject.c
index 5d3b66c..40340b4 100644
--- a/Objects/genobject.c
+++ b/Objects/genobject.c
@@ -27,8 +27,7 @@
/* If `gen` is a coroutine, and if it was never awaited on,
issue a RuntimeWarning. */
if (gen->gi_code != NULL
- && ((PyCodeObject *)gen->gi_code)->co_flags & (CO_COROUTINE
- | CO_ITERABLE_COROUTINE)
+ && ((PyCodeObject *)gen->gi_code)->co_flags & CO_COROUTINE
&& gen->gi_frame != NULL
&& gen->gi_frame->f_lasti == -1
&& !PyErr_Occurred()
@@ -86,8 +85,10 @@
PyObject *result;
if (gen->gi_running) {
- PyErr_SetString(PyExc_ValueError,
- "generator already executing");
+ char *msg = "generator already executing";
+ if (PyCoro_CheckExact(gen))
+ msg = "coroutine already executing";
+ PyErr_SetString(PyExc_ValueError, msg);
return NULL;
}
if (f == NULL || f->f_stacktop == NULL) {
@@ -99,9 +100,12 @@
if (f->f_lasti == -1) {
if (arg && arg != Py_None) {
- PyErr_SetString(PyExc_TypeError,
- "can't send non-None value to a "
- "just-started generator");
+ char *msg = "can't send non-None value to a "
+ "just-started generator";
+ if (PyCoro_CheckExact(gen))
+ msg = "can't send non-None value to a "
+ "just-started coroutine";
+ PyErr_SetString(PyExc_TypeError, msg);
return NULL;
}
} else {
@@ -151,14 +155,16 @@
(CO_FUTURE_GENERATOR_STOP | CO_COROUTINE | CO_ITERABLE_COROUTINE))
{
PyObject *exc, *val, *val2, *tb;
+ char *msg = "generator raised StopIteration";
+ if (PyCoro_CheckExact(gen))
+ msg = "coroutine raised StopIteration";
PyErr_Fetch(&exc, &val, &tb);
PyErr_NormalizeException(&exc, &val, &tb);
if (tb != NULL)
PyException_SetTraceback(val, tb);
Py_DECREF(exc);
Py_XDECREF(tb);
- PyErr_SetString(PyExc_RuntimeError,
- "generator raised StopIteration");
+ PyErr_SetString(PyExc_RuntimeError, msg);
PyErr_Fetch(&exc, &val2, &tb);
PyErr_NormalizeException(&exc, &val2, &tb);
Py_INCREF(val);
@@ -288,9 +294,11 @@
PyErr_SetNone(PyExc_GeneratorExit);
retval = gen_send_ex(gen, Py_None, 1);
if (retval) {
+ char *msg = "generator ignored GeneratorExit";
+ if (PyCoro_CheckExact(gen))
+ msg = "coroutine ignored GeneratorExit";
Py_DECREF(retval);
- PyErr_SetString(PyExc_RuntimeError,
- "generator ignored GeneratorExit");
+ PyErr_SetString(PyExc_RuntimeError, msg);
return NULL;
}
if (PyErr_ExceptionMatches(PyExc_StopIteration)
@@ -432,12 +440,6 @@
static PyObject *
gen_iternext(PyGenObject *gen)
{
- if (((PyCodeObject*)gen->gi_code)->co_flags & CO_COROUTINE) {
- PyErr_SetString(PyExc_TypeError,
- "coroutine-objects do not support iteration");
- return NULL;
- }
-
return gen_send_ex(gen, NULL, 0);
}
@@ -494,14 +496,8 @@
static PyObject *
gen_repr(PyGenObject *gen)
{
- if (PyGen_CheckCoroutineExact(gen)) {
- return PyUnicode_FromFormat("<coroutine object %S at %p>",
- gen->gi_qualname, gen);
- }
- else {
- return PyUnicode_FromFormat("<generator object %S at %p>",
- gen->gi_qualname, gen);
- }
+ return PyUnicode_FromFormat("<generator object %S at %p>",
+ gen->gi_qualname, gen);
}
static PyObject *
@@ -537,19 +533,6 @@
return op->gi_qualname;
}
-static PyObject *
-gen_get_iter(PyGenObject *gen)
-{
- if (((PyCodeObject*)gen->gi_code)->co_flags & CO_COROUTINE) {
- PyErr_SetString(PyExc_TypeError,
- "coroutine-objects do not support iteration");
- return NULL;
- }
-
- Py_INCREF(gen);
- return (PyObject *)gen;
-}
-
static int
gen_set_qualname(PyGenObject *op, PyObject *value)
{
@@ -619,7 +602,7 @@
0, /* tp_clear */
0, /* tp_richcompare */
offsetof(PyGenObject, gi_weakreflist), /* tp_weaklistoffset */
- (getiterfunc)gen_get_iter, /* tp_iter */
+ PyObject_SelfIter, /* tp_iter */
(iternextfunc)gen_iternext, /* tp_iternext */
gen_methods, /* tp_methods */
gen_memberlist, /* tp_members */
@@ -645,10 +628,11 @@
_PyGen_Finalize, /* tp_finalize */
};
-PyObject *
-PyGen_NewWithQualName(PyFrameObject *f, PyObject *name, PyObject *qualname)
+static PyObject *
+gen_new_with_qualname(PyTypeObject *type, PyFrameObject *f,
+ PyObject *name, PyObject *qualname)
{
- PyGenObject *gen = PyObject_GC_New(PyGenObject, &PyGen_Type);
+ PyGenObject *gen = PyObject_GC_New(PyGenObject, type);
if (gen == NULL) {
Py_DECREF(f);
return NULL;
@@ -674,9 +658,15 @@
}
PyObject *
+PyGen_NewWithQualName(PyFrameObject *f, PyObject *name, PyObject *qualname)
+{
+ return gen_new_with_qualname(&PyGen_Type, f, name, qualname);
+}
+
+PyObject *
PyGen_New(PyFrameObject *f)
{
- return PyGen_NewWithQualName(f, NULL, NULL);
+ return gen_new_with_qualname(&PyGen_Type, f, NULL, NULL);
}
int
@@ -697,6 +687,25 @@
return 0;
}
+/* Coroutine Object */
+
+typedef struct {
+ PyObject_HEAD
+ PyCoroObject *cw_coroutine;
+} PyCoroWrapper;
+
+static int
+gen_is_coroutine(PyObject *o)
+{
+ if (PyGen_CheckExact(o)) {
+ PyCodeObject *code = (PyCodeObject *)((PyGenObject*)o)->gi_code;
+ if (code->co_flags & CO_ITERABLE_COROUTINE) {
+ return 1;
+ }
+ }
+ return 0;
+}
+
/*
* This helper function returns an awaitable for `o`:
* - `o` if `o` is a coroutine-object;
@@ -706,13 +715,13 @@
* an awaitable and returns NULL.
*/
PyObject *
-_PyGen_GetAwaitableIter(PyObject *o)
+_PyCoro_GetAwaitableIter(PyObject *o)
{
unaryfunc getter = NULL;
PyTypeObject *ot;
- if (PyGen_CheckCoroutineExact(o)) {
- /* Fast path. It's a central function for 'await'. */
+ if (PyCoro_CheckExact(o) || gen_is_coroutine(o)) {
+ /* 'o' is a coroutine. */
Py_INCREF(o);
return o;
}
@@ -724,22 +733,19 @@
if (getter != NULL) {
PyObject *res = (*getter)(o);
if (res != NULL) {
- if (!PyIter_Check(res)) {
+ if (PyCoro_CheckExact(res) || gen_is_coroutine(res)) {
+ /* __await__ must return an *iterator*, not
+ a coroutine or another awaitable (see PEP 492) */
+ PyErr_SetString(PyExc_TypeError,
+ "__await__() returned a coroutine");
+ Py_CLEAR(res);
+ } else if (!PyIter_Check(res)) {
PyErr_Format(PyExc_TypeError,
"__await__() returned non-iterator "
"of type '%.100s'",
Py_TYPE(res)->tp_name);
Py_CLEAR(res);
}
- else {
- if (PyGen_CheckCoroutineExact(res)) {
- /* __await__ must return an *iterator*, not
- a coroutine or another awaitable (see PEP 492) */
- PyErr_SetString(PyExc_TypeError,
- "__await__() returned a coroutine");
- Py_CLEAR(res);
- }
- }
}
return res;
}
@@ -747,6 +753,211 @@
PyErr_Format(PyExc_TypeError,
"object %.100s can't be used in 'await' expression",
ot->tp_name);
-
return NULL;
}
+
+static PyObject *
+coro_repr(PyCoroObject *coro)
+{
+ return PyUnicode_FromFormat("<coroutine object %S at %p>",
+ coro->cr_qualname, coro);
+}
+
+static PyObject *
+coro_await(PyCoroObject *coro)
+{
+ PyCoroWrapper *cw = PyObject_GC_New(PyCoroWrapper, &_PyCoroWrapper_Type);
+ if (cw == NULL) {
+ return NULL;
+ }
+ Py_INCREF(coro);
+ cw->cw_coroutine = coro;
+ _PyObject_GC_TRACK(cw);
+ return (PyObject *)cw;
+}
+
+static PyGetSetDef coro_getsetlist[] = {
+ {"__name__", (getter)gen_get_name, (setter)gen_set_name,
+ PyDoc_STR("name of the coroutine")},
+ {"__qualname__", (getter)gen_get_qualname, (setter)gen_set_qualname,
+ PyDoc_STR("qualified name of the coroutine")},
+ {NULL} /* Sentinel */
+};
+
+static PyMemberDef coro_memberlist[] = {
+ {"cr_frame", T_OBJECT, offsetof(PyCoroObject, cr_frame), READONLY},
+ {"cr_running", T_BOOL, offsetof(PyCoroObject, cr_running), READONLY},
+ {"cr_code", T_OBJECT, offsetof(PyCoroObject, cr_code), READONLY},
+ {NULL} /* Sentinel */
+};
+
+PyDoc_STRVAR(coro_send_doc,
+"send(arg) -> send 'arg' into coroutine,\n\
+return next yielded value or raise StopIteration.");
+
+PyDoc_STRVAR(coro_throw_doc,
+"throw(typ[,val[,tb]]) -> raise exception in coroutine,\n\
+return next yielded value or raise StopIteration.");
+
+PyDoc_STRVAR(coro_close_doc,
+"close() -> raise GeneratorExit inside coroutine.");
+
+static PyMethodDef coro_methods[] = {
+ {"send",(PyCFunction)_PyGen_Send, METH_O, coro_send_doc},
+ {"throw",(PyCFunction)gen_throw, METH_VARARGS, coro_throw_doc},
+ {"close",(PyCFunction)gen_close, METH_NOARGS, coro_close_doc},
+ {NULL, NULL} /* Sentinel */
+};
+
+static PyAsyncMethods coro_as_async = {
+ (unaryfunc)coro_await, /* am_await */
+ 0, /* am_aiter */
+ 0 /* am_anext */
+};
+
+PyTypeObject PyCoro_Type = {
+ PyVarObject_HEAD_INIT(&PyType_Type, 0)
+ "coroutine", /* tp_name */
+ sizeof(PyCoroObject), /* tp_basicsize */
+ 0, /* tp_itemsize */
+ /* methods */
+ (destructor)gen_dealloc, /* tp_dealloc */
+ 0, /* tp_print */
+ 0, /* tp_getattr */
+ 0, /* tp_setattr */
+ &coro_as_async, /* tp_as_async */
+ (reprfunc)coro_repr, /* tp_repr */
+ 0, /* tp_as_number */
+ 0, /* tp_as_sequence */
+ 0, /* tp_as_mapping */
+ 0, /* tp_hash */
+ 0, /* tp_call */
+ 0, /* tp_str */
+ PyObject_GenericGetAttr, /* tp_getattro */
+ 0, /* tp_setattro */
+ 0, /* tp_as_buffer */
+ Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC |
+ Py_TPFLAGS_HAVE_FINALIZE, /* tp_flags */
+ 0, /* tp_doc */
+ (traverseproc)gen_traverse, /* tp_traverse */
+ 0, /* tp_clear */
+ 0, /* tp_richcompare */
+ offsetof(PyCoroObject, cr_weakreflist), /* tp_weaklistoffset */
+ 0, /* tp_iter */
+ 0, /* tp_iternext */
+ coro_methods, /* tp_methods */
+ coro_memberlist, /* tp_members */
+ coro_getsetlist, /* tp_getset */
+ 0, /* tp_base */
+ 0, /* tp_dict */
+ 0, /* tp_descr_get */
+ 0, /* tp_descr_set */
+ 0, /* tp_dictoffset */
+ 0, /* tp_init */
+ 0, /* tp_alloc */
+ 0, /* tp_new */
+ 0, /* tp_free */
+ 0, /* tp_is_gc */
+ 0, /* tp_bases */
+ 0, /* tp_mro */
+ 0, /* tp_cache */
+ 0, /* tp_subclasses */
+ 0, /* tp_weaklist */
+ 0, /* tp_del */
+ 0, /* tp_version_tag */
+ _PyGen_Finalize, /* tp_finalize */
+};
+
+static void
+coro_wrapper_dealloc(PyCoroWrapper *cw)
+{
+ _PyObject_GC_UNTRACK((PyObject *)cw);
+ Py_CLEAR(cw->cw_coroutine);
+ PyObject_GC_Del(cw);
+}
+
+static PyObject *
+coro_wrapper_iternext(PyCoroWrapper *cw)
+{
+ return gen_send_ex((PyGenObject *)cw->cw_coroutine, NULL, 0);
+}
+
+static PyObject *
+coro_wrapper_send(PyCoroWrapper *cw, PyObject *arg)
+{
+ return gen_send_ex((PyGenObject *)cw->cw_coroutine, arg, 0);
+}
+
+static PyObject *
+coro_wrapper_throw(PyCoroWrapper *cw, PyObject *args)
+{
+ return gen_throw((PyGenObject *)cw->cw_coroutine, args);
+}
+
+static PyObject *
+coro_wrapper_close(PyCoroWrapper *cw, PyObject *args)
+{
+ return gen_close((PyGenObject *)cw->cw_coroutine, args);
+}
+
+static int
+coro_wrapper_traverse(PyCoroWrapper *cw, visitproc visit, void *arg)
+{
+ Py_VISIT((PyObject *)cw->cw_coroutine);
+ return 0;
+}
+
+static PyMethodDef coro_wrapper_methods[] = {
+ {"send",(PyCFunction)coro_wrapper_send, METH_O, send_doc},
+ {"throw",(PyCFunction)coro_wrapper_throw, METH_VARARGS, throw_doc},
+ {"close",(PyCFunction)coro_wrapper_close, METH_NOARGS, close_doc},
+ {NULL, NULL} /* Sentinel */
+};
+
+PyTypeObject _PyCoroWrapper_Type = {
+ PyVarObject_HEAD_INIT(&PyType_Type, 0)
+ "coroutine_wrapper",
+ sizeof(PyCoroWrapper), /* tp_basicsize */
+ 0, /* tp_itemsize */
+ (destructor)coro_wrapper_dealloc, /* destructor tp_dealloc */
+ 0, /* tp_print */
+ 0, /* tp_getattr */
+ 0, /* tp_setattr */
+ 0, /* tp_as_async */
+ 0, /* tp_repr */
+ 0, /* tp_as_number */
+ 0, /* tp_as_sequence */
+ 0, /* tp_as_mapping */
+ 0, /* tp_hash */
+ 0, /* tp_call */
+ 0, /* tp_str */
+ PyObject_GenericGetAttr, /* tp_getattro */
+ 0, /* tp_setattro */
+ 0, /* tp_as_buffer */
+ Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC, /* tp_flags */
+ "A wrapper object implementing __await__ for coroutines.",
+ (traverseproc)coro_wrapper_traverse, /* tp_traverse */
+ 0, /* tp_clear */
+ 0, /* tp_richcompare */
+ 0, /* tp_weaklistoffset */
+ PyObject_SelfIter, /* tp_iter */
+ (iternextfunc)coro_wrapper_iternext, /* tp_iternext */
+ coro_wrapper_methods, /* tp_methods */
+ 0, /* tp_members */
+ 0, /* tp_getset */
+ 0, /* tp_base */
+ 0, /* tp_dict */
+ 0, /* tp_descr_get */
+ 0, /* tp_descr_set */
+ 0, /* tp_dictoffset */
+ 0, /* tp_init */
+ 0, /* tp_alloc */
+ 0, /* tp_new */
+ PyObject_Del, /* tp_free */
+};
+
+PyObject *
+PyCoro_New(PyFrameObject *f, PyObject *name, PyObject *qualname)
+{
+ return gen_new_with_qualname(&PyCoro_Type, f, name, qualname);
+}