From 7dd549eb08939e1927fba818116f5202e76f8d73 Mon Sep 17 00:00:00 2001
From: Paulo Henrique Silva <ph.silva@carta.com>
Date: Tue, 24 Mar 2020 23:19:58 -0300
Subject: [PATCH] bpo-1635741: Port _functools module to multiphase
 initialization (PEP 489) (GH-19151)

---
 ...2020-03-24-22-26-26.bpo-1635741.AB38ot.rst |  2 +
 Modules/_functoolsmodule.c                    | 60 ++++++++++---------
 2 files changed, 34 insertions(+), 28 deletions(-)
 create mode 100644 Misc/NEWS.d/next/Core and Builtins/2020-03-24-22-26-26.bpo-1635741.AB38ot.rst

diff --git a/Misc/NEWS.d/next/Core and Builtins/2020-03-24-22-26-26.bpo-1635741.AB38ot.rst b/Misc/NEWS.d/next/Core and Builtins/2020-03-24-22-26-26.bpo-1635741.AB38ot.rst
new file mode 100644
index 00000000000..1a611628343
--- /dev/null
+++ b/Misc/NEWS.d/next/Core and Builtins/2020-03-24-22-26-26.bpo-1635741.AB38ot.rst	
@@ -0,0 +1,2 @@
+Port _functools module to multiphase initialization (PEP 489). Patch by
+Paulo Henrique Silva.
diff --git a/Modules/_functoolsmodule.c b/Modules/_functoolsmodule.c
index ff733b8d45a..2e27d48b147 100644
--- a/Modules/_functoolsmodule.c
+++ b/Modules/_functoolsmodule.c
@@ -1400,10 +1400,10 @@ static PyTypeObject lru_cache_type = {
 
 /* module level code ********************************************************/
 
-PyDoc_STRVAR(module_doc,
+PyDoc_STRVAR(_functools_doc,
 "Tools that operate on functions.");
 
-static PyMethodDef module_methods[] = {
+static PyMethodDef _functools_methods[] = {
     {"reduce",          functools_reduce,     METH_VARARGS, functools_reduce_doc},
     {"cmp_to_key",      (PyCFunction)(void(*)(void))functools_cmp_to_key,
      METH_VARARGS | METH_KEYWORDS, functools_cmp_to_key_doc},
@@ -1411,47 +1411,51 @@ static PyMethodDef module_methods[] = {
 };
 
 static void
-module_free(void *m)
+_functools_free(void *m)
 {
     Py_CLEAR(kwd_mark);
 }
 
-static struct PyModuleDef _functoolsmodule = {
-    PyModuleDef_HEAD_INIT,
-    "_functools",
-    module_doc,
-    -1,
-    module_methods,
-    NULL,
-    NULL,
-    NULL,
-    module_free,
-};
-
-PyMODINIT_FUNC
-PyInit__functools(void)
+static int
+_functools_exec(PyObject *module)
 {
-    PyObject *m;
     PyTypeObject *typelist[] = {
         &partial_type,
         &lru_cache_type
     };
 
-    m = PyModule_Create(&_functoolsmodule);
-    if (m == NULL)
-        return NULL;
-
     kwd_mark = _PyObject_CallNoArg((PyObject *)&PyBaseObject_Type);
     if (!kwd_mark) {
-        Py_DECREF(m);
-        return NULL;
+        return -1;
     }
 
     for (size_t i = 0; i < Py_ARRAY_LENGTH(typelist); i++) {
-        if (PyModule_AddType(m, typelist[i]) < 0) {
-            Py_DECREF(m);
-            return NULL;
+        if (PyModule_AddType(module, typelist[i]) < 0) {
+            return -1;
         }
     }
-    return m;
+    return 0;
+}
+
+static struct PyModuleDef_Slot _functools_slots[] = {
+    {Py_mod_exec, _functools_exec},
+    {0, NULL}
+};
+
+static struct PyModuleDef _functools_module = {
+    PyModuleDef_HEAD_INIT,
+    "_functools",
+    _functools_doc,
+    0,
+    _functools_methods,
+    _functools_slots,
+    NULL,
+    NULL,
+    _functools_free,
+};
+
+PyMODINIT_FUNC
+PyInit__functools(void)
+{
+    return PyModuleDef_Init(&_functools_module);
 }