bpo-1635741: port multiprocessing to multiphase init

Misc/NEWS.d/next/Core and Builtins/2020-07-07-16-10-52.bpo-1635741.zU-H_n.rst

@@ -0,0 +1 @@
+Port :mod:`multiprocessing` to multi-phase initialization

Modules/_multiprocessing/multiprocessing.c

@@ -139,35 +139,17 @@ static PyMethodDef module_methods[] ={
  * Initialize
  */
 
-static struct PyModuleDef multiprocessing_module ={
- PyModuleDef_HEAD_INIT,
- "_multiprocessing",
- NULL,
- -1,
- module_methods,
- NULL,
- NULL,
- NULL,
- NULL
-};
-
-
-PyMODINIT_FUNC
-PyInit__multiprocessing(void)
+static int
+multiprocessing_exec(PyObject *module)
 {
- PyObject *module, *temp, *value = NULL;
-
- /* Initialize module */
- module = PyModule_Create(&multiprocessing_module);
- if (!module)
- return NULL;
-
 #if defined(MS_WINDOWS) || \
  (defined(HAVE_SEM_OPEN) && !defined(POSIX_SEMAPHORES_NOT_ENABLED))
+
  /* Add _PyMp_SemLock type to module */
- if (PyType_Ready(&_PyMp_SemLockType) < 0)
- return NULL;
- Py_INCREF(&_PyMp_SemLockType);
+ if (PyModule_AddType(module, &_PyMp_SemLockType) < 0){
+ return -1;
+ }
+
 {
  PyObject *py_sem_value_max;
  /* Some systems define SEM_VALUE_MAX as an unsigned value that
@@ -179,25 +161,41 @@ PyInit__multiprocessing(void)
  py_sem_value_max = PyLong_FromLong(INT_MAX);
  else
  py_sem_value_max = PyLong_FromLong(SEM_VALUE_MAX);
- if (py_sem_value_max == NULL)
- return NULL;
- PyDict_SetItemString(_PyMp_SemLockType.tp_dict, "SEM_VALUE_MAX",
- py_sem_value_max);
+
+ if (py_sem_value_max == NULL){
+ Py_DECREF(py_sem_value_max);
+ return -1;
+ }
+ if (PyDict_SetItemString(_PyMp_SemLockType.tp_dict, "SEM_VALUE_MAX",
+ py_sem_value_max) < 0){
+ Py_DECREF(py_sem_value_max);
+ return -1;
+ }
+ Py_DECREF(py_sem_value_max);
  }
- PyModule_AddObject(module, "SemLock", (PyObject*)&_PyMp_SemLockType);
+
 #endif
 
  /* Add configuration macros */
- temp = PyDict_New();
- if (!temp)
- return NULL;
+ PyObject *flags = PyDict_New();
+ if (!flags){
+ return -1;
+ }
 
-#define ADD_FLAG(name) \
- value = Py_BuildValue("i", name); \
- if (value == NULL){Py_DECREF(temp); return NULL} \
- if (PyDict_SetItemString(temp, #name, value) < 0){\
- Py_DECREF(temp); Py_DECREF(value); return NULL} \
- Py_DECREF(value)
+#define ADD_FLAG(name) \
+ do{\
+ PyObject *value = PyLong_FromLong(name); \
+ if (value == NULL){\
+ Py_DECREF(flags); \
+ return -1; \
+ } \
+ if (PyDict_SetItemString(flags, #name, value) < 0){\
+ Py_DECREF(flags); \
+ Py_DECREF(value); \
+ return -1; \
+ } \
+ Py_DECREF(value); \
+ } while (0)
 
 #if defined(HAVE_SEM_OPEN) && !defined(POSIX_SEMAPHORES_NOT_ENABLED)
  ADD_FLAG(HAVE_SEM_OPEN);
@@ -212,8 +210,28 @@ PyInit__multiprocessing(void)
  ADD_FLAG(HAVE_BROKEN_SEM_UNLINK);
 #endif
 
- if (PyModule_AddObject(module, "flags", temp) < 0)
- return NULL;
+ if (PyModule_AddObject(module, "flags", flags) < 0){
+ Py_DECREF(flags);
+ return -1;
+ }
+
+ return 0;
+}
+
+static PyModuleDef_Slot multiprocessing_slots[] ={
+{Py_mod_exec, multiprocessing_exec},
+{0, NULL}
+};
 
- return module;
+static struct PyModuleDef multiprocessing_module ={
+ PyModuleDef_HEAD_INIT,
+ .m_name = "_multiprocessing",
+ .m_methods = module_methods,
+ .m_slots = multiprocessing_slots,
+};
+
+PyMODINIT_FUNC
+PyInit__multiprocessing(void)
+{
+ return PyModuleDef_Init(&multiprocessing_module);
 }