From 7d7956833cc37a9d42807cbfeb7dcc041970f579 Mon Sep 17 00:00:00 2001
From: Hai Shi <shihai1992@gmail.com>
Date: Mon, 17 Feb 2020 21:49:26 +0800
Subject: [PATCH] bpo-1635741: Port _contextvars module to multiphase
 initialization (PEP 489) (GH-18374)

---
 ...2020-02-06-09-00-35.bpo-1635741.oaxe1j.rst |  1 +
 Modules/_contextvarsmodule.c                  | 73 ++++++++++---------
 2 files changed, 39 insertions(+), 35 deletions(-)
 create mode 100644 Misc/NEWS.d/next/Core and Builtins/2020-02-06-09-00-35.bpo-1635741.oaxe1j.rst

diff --git a/Misc/NEWS.d/next/Core and Builtins/2020-02-06-09-00-35.bpo-1635741.oaxe1j.rst b/Misc/NEWS.d/next/Core and Builtins/2020-02-06-09-00-35.bpo-1635741.oaxe1j.rst
new file mode 100644
index 00000000000..49336f02a3e
--- /dev/null
+++ b/Misc/NEWS.d/next/Core and Builtins/2020-02-06-09-00-35.bpo-1635741.oaxe1j.rst	
@@ -0,0 +1 @@
+Port _contextvars extension module to multiphase initialization (:pep:`489`).
\ No newline at end of file
diff --git a/Modules/_contextvarsmodule.c b/Modules/_contextvarsmodule.c
index 1abcdbfa921..d6d7f375d12 100644
--- a/Modules/_contextvarsmodule.c
+++ b/Modules/_contextvarsmodule.c
@@ -27,13 +27,48 @@ static PyMethodDef _contextvars_methods[] = {
     {NULL, NULL}
 };
 
+static int
+_contextvars_exec(PyObject *m)
+{
+    Py_INCREF(&PyContext_Type);
+    if (PyModule_AddObject(m, "Context",
+                           (PyObject *)&PyContext_Type) < 0)
+    {
+        Py_DECREF(&PyContext_Type);
+        return -1;
+    }
+
+    Py_INCREF(&PyContextVar_Type);
+    if (PyModule_AddObject(m, "ContextVar",
+                           (PyObject *)&PyContextVar_Type) < 0)
+    {
+        Py_DECREF(&PyContextVar_Type);
+        return -1;
+    }
+
+    Py_INCREF(&PyContextToken_Type);
+    if (PyModule_AddObject(m, "Token",
+                           (PyObject *)&PyContextToken_Type) < 0)
+    {
+        Py_DECREF(&PyContextToken_Type);
+        return -1;
+    }
+
+    return 0;
+}
+
+static struct PyModuleDef_Slot _contextvars_slots[] = {
+    {Py_mod_exec, _contextvars_exec},
+    {0, NULL}
+};
+
 static struct PyModuleDef _contextvarsmodule = {
     PyModuleDef_HEAD_INIT,      /* m_base */
     "_contextvars",             /* m_name */
     module_doc,                 /* m_doc */
-    -1,                         /* m_size */
+    0,                          /* m_size */
     _contextvars_methods,       /* m_methods */
-    NULL,                       /* m_slots */
+    _contextvars_slots,         /* m_slots */
     NULL,                       /* m_traverse */
     NULL,                       /* m_clear */
     NULL,                       /* m_free */
@@ -42,37 +77,5 @@ static struct PyModuleDef _contextvarsmodule = {
 PyMODINIT_FUNC
 PyInit__contextvars(void)
 {
-    PyObject *m = PyModule_Create(&_contextvarsmodule);
-    if (m == NULL) {
-        return NULL;
-    }
-
-    Py_INCREF(&PyContext_Type);
-    if (PyModule_AddObject(m, "Context",
-                           (PyObject *)&PyContext_Type) < 0)
-    {
-        Py_DECREF(&PyContext_Type);
-        Py_DECREF(m);
-        return NULL;
-    }
-
-    Py_INCREF(&PyContextVar_Type);
-    if (PyModule_AddObject(m, "ContextVar",
-                           (PyObject *)&PyContextVar_Type) < 0)
-    {
-        Py_DECREF(&PyContextVar_Type);
-        Py_DECREF(m);
-        return NULL;
-    }
-
-    Py_INCREF(&PyContextToken_Type);
-    if (PyModule_AddObject(m, "Token",
-                           (PyObject *)&PyContextToken_Type) < 0)
-    {
-        Py_DECREF(&PyContextToken_Type);
-        Py_DECREF(m);
-        return NULL;
-    }
-
-    return m;
+    return PyModuleDef_Init(&_contextvarsmodule);
 }