Convert pocketfft_umath to multi-phase init (PEP 489)

AA-Turner · AA-Turner · commit 074fb122dcfe · 2025-05-22T03:49:29.000+01:00
diff --git a/numpy/fft/_pocketfft_umath.cpp b/numpy/fft/_pocketfft_umath.cpp
@@ -388,41 +388,42 @@ add_gufuncs(PyObject *dictionary) {
     return 0;
 }
 
-static struct PyModuleDef moduledef = {
-    PyModuleDef_HEAD_INIT,
-    "_multiarray_umath",
-    NULL,
-    -1,
-    NULL,
-    NULL,
-    NULL,
-    NULL,
-    NULL
-};
-
-/* Initialization function for the module */
-PyMODINIT_FUNC PyInit__pocketfft_umath(void)
+static int
+_pocketfft_umath_exec(PyObject *m)
 {
-    PyObject *m = PyModule_Create(&moduledef);
-    if (m == NULL) {
-        return NULL;
-    }
-
     /* Import the array and ufunc objects */
-    import_array();
-    import_ufunc();
+    import_array1(-1);
+    import_umath1(-1);
 
     PyObject *d = PyModule_GetDict(m);
     if (add_gufuncs(d) < 0) {
         Py_DECREF(d);
         Py_DECREF(m);
-        return NULL;
+        return -1;
     }
 
-#if Py_GIL_DISABLED
-    // signal this module supports running with the GIL disabled
-    PyUnstable_Module_SetGIL(m, Py_MOD_GIL_NOT_USED);
+    return 0;
+}
+
+static struct PyModuleDef_Slot _pocketfft_umath_slots[] = {
+    {Py_mod_exec, (void*)_pocketfft_umath_exec},
+#if PY_VERSION_HEX >= 0x030c00f0  // Python 3.12+
+    {Py_mod_multiple_interpreters, Py_MOD_MULTIPLE_INTERPRETERS_NOT_SUPPORTED},
 #endif
+#if PY_VERSION_HEX >= 0x030d00f0  // Python 3.13+
+    // signal that this module supports running without an active GIL
+    {Py_mod_gil, Py_MOD_GIL_NOT_USED},
+#endif
+    {0, NULL},
+};
+
+static struct PyModuleDef moduledef = {
+    .m_base = PyModuleDef_HEAD_INIT,
+    .m_name = "_pocketfft_umath",
+    .m_size = 0,
+    .m_slots = _pocketfft_umath_slots,
+};
 
-    return m;
+PyMODINIT_FUNC PyInit__pocketfft_umath(void) {
+    return PyModuleDef_Init(&moduledef);
 }
