Stackless issue python#265: Fix (invalid) function cast warnings with…

… gcc 8

* fix PyChannel_Send_M

The implementation was buggy. This affects only users of the C-API,
that call PyChannel_Send() and PyChannel_Send_nr() for calls from
outside of the interpreter (with no main-tasklet).

* fix PyChannel_Receive_M and tasklet_new

If called from outside of the interpreter the behavior was undefined.
(Calling a C-function with wrong number of arguments).

* fix __reduce__ / __reduce_ex__

Avoid undefined behavior, if Stackless classes implement __reduce__()
and __reduce_ex__() using a single C-function.
__reduce_ex__ now checks the type of its argument.

* fix the signature of tp_clear functions

Return type is 'int', not 'void'.

* add missing arguments to C-function definitions

Most (getter)-functions, (setter)-functions and (PyCFunction)-functions
with flag METH_NOARGS lack an unused last argument, "void *" for
(getter) and (setter), "PyObject *" for (PyCFunction)-functions.
This commit adds these arguments.

* Fix invalid function cast warnings

Fix invalid function cast warnings with gcc 8 for method conventions
different from METH_NOARGS, METH_O and METH_VARARGS excluding Argument
Clinic generated code.

Include/internal/pycore_stackless.h

@@ -780,7 +780,7 @@ PyObject* slp_context_run_callback(PyFrameObject *f, int exc, PyObject *result);
      (ts->st.runflags & PY_WATCHDOG_IGNORE_NESTING))
 
 /* Interpreter shutdown and thread state access */
-PyObject * slp_getthreads(PyObject *self);
+PyObject * slp_getthreads(PyObject *self, PyObject *unused);
 void slp_head_lock(void);
 void slp_head_unlock(void);
 #define SLP_HEAD_LOCK() slp_head_lock()

Modules/_pickle.c

@@ -4689,7 +4689,7 @@ Pickler_set_memo(PicklerObject *self, PyObject *obj, void *Py_UNUSED(ignored))
 
 #ifdef STACKLESS
 static PyObject *
-Pickler_get_module_dict_ids(PicklerObject *p)
+Pickler_get_module_dict_ids(PicklerObject *p, void *closure)
 {
         if (p->module_dict_ids == NULL)
                 PyErr_SetString(PyExc_AttributeError, "module_dict_ids");
@@ -4699,7 +4699,7 @@ Pickler_get_module_dict_ids(PicklerObject *p)
 }
 
 static int
-Pickler_set_module_dict_ids(PicklerObject *p, PyObject *v)
+Pickler_set_module_dict_ids(PicklerObject *p, PyObject *v, void *closure)
 {
         if (v == NULL) {
                 PyErr_SetString(PyExc_TypeError,

Stackless/changelog.txt

@@ -9,6 +9,26 @@ What's New in Stackless 3.X.X?
 
 *Release date: 20XX-XX-XX*
 
+- https://github.com/stackless-dev/stackless/issues/265
+  Fix invalid function cast warnings with gcc 8 for method conventions
+  different from METH_NOARGS, METH_O and METH_VARARGS excluding Argument Clinic
+  generated code.
+
+- https://github.com/stackless-dev/stackless/issues/265
+  Most (getter)-functions, (setter)-functions and (PyCFunction)-functions with
+  flag METH_NOARGS used to lack an unused last argument, "void *" for (getter)
+  and (setter), "PyObject *" for (PyCFunction)-functions.
+
+- https://github.com/stackless-dev/stackless/issues/265
+  Avoid undefined behavior, if Stackless classes implement __reduce__() and
+  __reduce_ex__() using a single C-function.
+
+- https://github.com/stackless-dev/stackless/issues/265
+  Fix C-API functions PyChannel_Send(), PyChannel_Send_nr(),
+  PyChannel_Receive(), PyChannel_Receive_nr(), and
+  PyObject_Call(&PyTasklet_Type, PyObject *args, PyObject *kwargs) if called
+  from outside of the interpreter (with no main-tasklet).
+
 - https://github.com/stackless-dev/stackless/issues/264
   Implement bpo-35134 for Stackless: move header Include/slp_tstate.h to
   Include/cpython/slp_tstate.h.

Stackless/core/cframeobject.c

@@ -66,7 +66,7 @@ cframe_traverse(PyCFrameObject *cf, visitproc visit, void *arg)
 
 /* clearing a cframe while the object still exists */
 
-static void
+static int
 cframe_clear(PyCFrameObject *cf)
 {
     /* The Python C-API documentation recomends to use Py_CLEAR() to release
@@ -86,6 +86,7 @@ cframe_clear(PyCFrameObject *cf)
     Py_XDECREF(tmp_ob1);
     Py_XDECREF(tmp_ob2);
     Py_XDECREF(tmp_ob3);
+    return 0;
 }
 
 
@@ -133,14 +134,19 @@ static PyObject * execute_soft_switchable_func(PyFrameObject *, int, PyObject *)
 SLP_DEF_INVALID_EXEC(execute_soft_switchable_func)
 
 static PyObject *
-cframe_reduce(PyCFrameObject *cf)
+cframe_reduce(PyCFrameObject *cf, PyObject *value)
 {
     PyObject *res = NULL, *exec_name = NULL;
     PyObject *params = NULL;
     int valid = 1;
     PyObject *obs[3];
     long i, n;
 
+    if (value && !PyLong_Check(value)) {
+        PyErr_SetString(PyExc_TypeError, "__reduce_ex__ argument should be an integer");
+        return NULL;
+    }
+
     if (cf->f_execute == execute_soft_switchable_func) {
         exec_name = (PyObject *) cf->any2;
         assert(cf->any2);
@@ -240,7 +246,7 @@ cframe_setstate(PyObject *self, PyObject *args)
 
 static PyMethodDef cframe_methods[] = {
     {"__reduce__",    (PyCFunction)cframe_reduce, METH_NOARGS, NULL},
-    {"__reduce_ex__", (PyCFunction)cframe_reduce, METH_VARARGS, NULL},
+    {"__reduce_ex__", (PyCFunction)cframe_reduce, METH_O, NULL},
     {"__setstate__",  (PyCFunction)cframe_setstate, METH_O, NULL},
     {NULL, NULL}
 };
@@ -386,8 +392,13 @@ slp_cframe_fini(void)
  */
 
 static PyObject *
-function_declaration_reduce(PyStacklessFunctionDeclarationObject *self)
+function_declaration_reduce(PyStacklessFunctionDeclarationObject *self, PyObject *value)
 {
+    if (value && !PyLong_Check(value)) {
+        PyErr_SetString(PyExc_TypeError, "__reduce_ex__ argument should be an integer");
+        return NULL;
+    }
+
     if (self->name == NULL || *self->name == '\0') {
         PyErr_SetString(PyExc_SystemError, "no function name");
         return NULL;
@@ -397,7 +408,7 @@ function_declaration_reduce(PyStacklessFunctionDeclarationObject *self)
 
 static PyMethodDef function_declaration_methods[] = {
     {"__reduce__",    (PyCFunction)function_declaration_reduce, METH_NOARGS, NULL},
-    {"__reduce_ex__", (PyCFunction)function_declaration_reduce, METH_VARARGS, NULL},
+    {"__reduce_ex__", (PyCFunction)function_declaration_reduce, METH_O, NULL},
     {NULL, NULL}
 };
 

Stackless/module/_teststackless.c

@@ -494,11 +494,11 @@ static PyObject* test_PyEval_EvalFrameEx(PyObject *self, PyObject *args, PyObjec
 static PyMethodDef _teststackless_methods[] = {
     {"softswitchablefunc",             _teststackless_softswitchabledemo,         METH_VARARGS | METH_STACKLESS,
     _teststackless_softswitchabledemo_doc},
-    { "test_cframe", (PyCFunction) test_cframe, METH_VARARGS | METH_KEYWORDS,
+    { "test_cframe", (PyCFunction)(void(*)(void))test_cframe, METH_VARARGS | METH_KEYWORDS,
     test_cframe__doc__ },
     { "test_cstate", (PyCFunction) test_cstate, METH_O,
     test_cstate__doc__ },
-    { "test_PyEval_EvalFrameEx", (PyCFunction) test_PyEval_EvalFrameEx, METH_VARARGS | METH_KEYWORDS,
+    { "test_PyEval_EvalFrameEx", (PyCFunction)(void(*)(void))test_PyEval_EvalFrameEx, METH_VARARGS | METH_KEYWORDS,
     test_PyEval_EvalFrameEx__doc__ },
     {NULL,              NULL}           /* sentinel */
 };

Stackless/module/channelobject.c

@@ -56,7 +56,7 @@ channel_traverse(PyChannelObject *ch, visitproc visit, void *arg)
     return 0;
 }
 
-static void
+static int
 channel_clear(PyObject *ob)
 {
     PyChannelObject *ch = (PyChannelObject *) ob;
@@ -74,6 +74,7 @@ channel_clear(PyObject *ob)
         ob = (PyObject *) slp_channel_remove(ch, NULL, NULL, NULL);
         Py_DECREF(ob);
     }
+    return 0;
 }
 
 static void
@@ -195,7 +196,7 @@ channel_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
 }
 
 static PyObject *
-channel_get_queue(PyChannelObject *self)
+channel_get_queue(PyChannelObject *self, void *closure)
 {
     PyObject *ret = (PyObject*) self->head;
 
@@ -208,11 +209,11 @@ channel_get_queue(PyChannelObject *self)
 PyObject *
 PyChannel_GetQueue(PyChannelObject *self)
 {
-    return channel_get_queue(self);
+    return channel_get_queue(self, NULL);
 }
 
 static PyObject *
-channel_get_closing(PyChannelObject *self)
+channel_get_closing(PyChannelObject *self, void *closure)
 {
     return PyBool_FromLong(self->flags.closing);
 }
@@ -224,7 +225,7 @@ PyChannel_GetClosing(PyChannelObject *self)
 }
 
 static PyObject *
-channel_get_closed(PyChannelObject *self)
+channel_get_closed(PyChannelObject *self, void *closure)
 {
     return PyBool_FromLong(self->flags.closing && self->balance == 0);
 }
@@ -237,13 +238,13 @@ PyChannel_GetClosed(PyChannelObject *self)
 
 
 static PyObject *
-channel_get_preference(PyChannelObject *self)
+channel_get_preference(PyChannelObject *self, void *closure)
 {
     return PyLong_FromLong(self->flags.preference);
 }
 
 static int
-channel_set_preference(PyChannelObject *self, PyObject *value)
+channel_set_preference(PyChannelObject *self, PyObject *value, void *closure)
 {
     int val;
 
@@ -267,13 +268,13 @@ PyChannel_SetPreference(PyChannelObject *self, int val)
 }
 
 static PyObject *
-channel_get_schedule_all(PyChannelObject *self)
+channel_get_schedule_all(PyChannelObject *self, void *closure)
 {
     return PyLong_FromLong(self->flags.schedule_all);
 }
 
 static int
-channel_set_schedule_all(PyChannelObject *self, PyObject *value)
+channel_set_schedule_all(PyChannelObject *self, PyObject *value, void *closure)
 {
     if (!PyLong_Check(value))
         TYPE_ERROR("preference must be set to a bool or integer", -1);
@@ -425,10 +426,13 @@ the sender will be blocked. Otherwise, the receiver will\n\
 be activated immediately, and the sender is put at the end of\n\
 the runnables list.");
 
+static PyObject *
+impl_channel_send(PyChannelObject *self, PyObject *arg);
+
 static PyObject *
 PyChannel_Send_M(PyChannelObject *self, PyObject *arg)
 {
-    PyMethodDef def = {"send", (PyCFunction)PyChannel_Send, METH_O};
+    PyMethodDef def = {"send", (PyCFunction)impl_channel_send, METH_O};
     return PyStackless_CallCMethod_Main(&def, (PyObject *) self, "O", arg);
 }
 
@@ -770,10 +774,16 @@ continue immediately, and the sender is put at the end of\n\
 the runnables list.\n\
 The above policy can be changed by setting channel flags.");
 
+static PyObject *
+PyChannel_Receive_cfunc(PyChannelObject *self, PyObject *unused)
+{
+    return PyChannel_Receive(self);
+}
+
 static PyObject *
 PyChannel_Receive_M(PyChannelObject *self)
 {
-    PyMethodDef def = {"receive", (PyCFunction)PyChannel_Receive, METH_NOARGS};
+    PyMethodDef def = {"receive", (PyCFunction)PyChannel_Receive_cfunc, METH_NOARGS};
     return PyStackless_CallCMethod_Main(&def, (PyObject *) self, NULL);
 }
 
@@ -809,7 +819,7 @@ PyChannel_Receive(PyChannelObject *self)
 }
 
 static PyObject *
-channel_receive(PyObject *self)
+channel_receive(PyObject *self, PyObject *unused)
 {
     return impl_channel_receive((PyChannelObject*)self);
 }
@@ -1059,7 +1069,7 @@ If the channel is not empty, the flag 'closing' becomes true.\n\
 If the channel is empty, the flag 'closed' becomes true.");
 
 static PyObject *
-channel_close(PyChannelObject *self)
+channel_close(PyChannelObject *self, PyObject *unused)
 {
     self->flags.closing = 1;
 
@@ -1077,7 +1087,7 @@ PyDoc_STRVAR(channel_open__doc__,
 "channel.open() -- reopen a channel. See channel.close.");
 
 static PyObject *
-channel_open(PyChannelObject *self)
+channel_open(PyChannelObject *self, PyObject *unused)
 {
     self->flags.closing = 0;
 
@@ -1095,12 +1105,17 @@ PyDoc_STRVAR(channel_reduce__doc__,
 "channel.__reduce__() -- currently does not distinguish threads.");
 
 static PyObject *
-channel_reduce(PyChannelObject * ch)
+channel_reduce(PyChannelObject * ch, PyObject *value)
 {
     PyObject *tup = NULL, *lis = NULL;
     PyTaskletObject *t;
     int i, n;
 
+    if (value && !PyLong_Check(value)) {
+        PyErr_SetString(PyExc_TypeError, "__reduce_ex__ argument should be an integer");
+        return NULL;
+    }
+
     lis = PyList_New(0);
     if (lis == NULL) goto err_exit;
     t = ch->head;
@@ -1179,7 +1194,7 @@ channel_methods[] = {
     channel_open__doc__},
     {"__reduce__",              (PCF)channel_reduce,        METH_NOARGS,
      channel_reduce__doc__},
-    {"__reduce_ex__",           (PCF)channel_reduce,        METH_VARARGS,
+    {"__reduce_ex__",           (PCF)channel_reduce,        METH_O,
      channel_reduce__doc__},
     {"__setstate__",            (PCF)channel_setstate,      METH_O,
      channel_setstate__doc__},

Stackless/module/scheduling.c

@@ -42,12 +42,13 @@ bomb_traverse(PyBombObject *bomb, visitproc visit, void *arg)
     return 0;
 }
 
-static void
+static int
 bomb_clear(PyBombObject *bomb)
 {
     Py_CLEAR(bomb->curexc_type);
     Py_CLEAR(bomb->curexc_value);
     Py_CLEAR(bomb->curexc_traceback);
+    return 0;
 }
 
 PyBombObject *
@@ -216,10 +217,15 @@ slp_bomb_explode(PyObject *_bomb)
 }
 
 static PyObject *
-bomb_reduce(PyBombObject *bomb)
+bomb_reduce(PyBombObject *bomb, PyObject *value)
 {
     PyObject *tup;
 
+    if (value && !PyLong_Check(value)) {
+        PyErr_SetString(PyExc_TypeError, "__reduce_ex__ argument should be an integer");
+        return NULL;
+    }
+
     tup = slp_into_tuple_with_nulls(&bomb->curexc_type, 3);
     if (tup != NULL)
         tup = Py_BuildValue("(O()O)", &PyBomb_Type, tup);
@@ -246,7 +252,7 @@ static PyMemberDef bomb_members[] = {
 
 static PyMethodDef bomb_methods[] = {
     {"__reduce__",              (PyCFunction)bomb_reduce,       METH_NOARGS},
-    {"__reduce_ex__",           (PyCFunction)bomb_reduce,       METH_VARARGS},
+    {"__reduce_ex__",           (PyCFunction)bomb_reduce,       METH_O},
     {"__setstate__",            (PyCFunction)bomb_setstate,     METH_O},
     {NULL,     NULL}             /* sentinel */
 };