[libgpiod][PATCH v2 11/14] bindings: python: include Python.h before other headers

[libgpiod][PATCH v2 11/14] bindings: python: include Python.h before other headers

[Vincent Fazio]

Per the Python C API reference manual [0], Python.h should be included
before other headers since it specifies some pre-processor definitions
that may differ from system defaults.

This was noticed when testing on CPython 3.15 [1] which emitted warnings
due to redefinitions of _XOPEN_SOURCE and _POSIX_C_SOURCE during builds
of the Python bindings.

Note: despite the manual stating that `PY_SSIZE_T_CLEAN` should also be
defined, it is intentionally not included. The Python bindings do not
use the `#` format specifier when parsing any arguments so defining it
provides no value [2] and it is deprecated in future versions.

[0]: https://docs.python.org/3/c-api/intro.html#include-files
[1]: https://github.com/python/cpython/commit/927eb448aad6436d794ec9f55780013e25609600
[2]: https://docs.python.org/3/c-api/arg.html#strings-and-buffers

Signed-off-by: Vincent Fazio <vfazio@gmail.com>
---
Changes in v2
 - Added white space to separate the Python.h include from others
   (Bartosz)
 - Added a comment beside the include to provide rationale (vfazio)
 - Expanded to include tests/system/ext.c for consistency (vfazio)
---
 bindings/python/gpiod/ext/internal.h | 4 +++-
 bindings/python/gpiod/ext/module.c   | 4 +++-
 bindings/python/tests/gpiosim/ext.c  | 4 +++-
 bindings/python/tests/system/ext.c   | 2 ++
 4 files changed, 11 insertions(+), 3 deletions(-)

diff --git a/bindings/python/gpiod/ext/internal.h b/bindings/python/gpiod/ext/internal.h
index 2996884..2c7ecd2 100644
--- a/bindings/python/gpiod/ext/internal.h
+++ b/bindings/python/gpiod/ext/internal.h
@@ -4,9 +4,11 @@
 #ifndef __LIBGPIOD_PYTHON_MODULE_H__
 #define __LIBGPIOD_PYTHON_MODULE_H__
 
-#include <gpiod.h>
+/* Import Python.h before other headers per API documentation */
 #include <Python.h>
 
+#include <gpiod.h>
+
 PyObject *Py_gpiod_SetErrFromErrno(void);
 unsigned int Py_gpiod_PyLongAsUnsignedInt(PyObject *pylong);
 void Py_gpiod_dealloc(PyObject *self);
diff --git a/bindings/python/gpiod/ext/module.c b/bindings/python/gpiod/ext/module.c
index 21ea519..8a9a07f 100644
--- a/bindings/python/gpiod/ext/module.c
+++ b/bindings/python/gpiod/ext/module.c
@@ -1,9 +1,11 @@
 // SPDX-License-Identifier: LGPL-2.1-or-later
 // SPDX-FileCopyrightText: 2022 Bartosz Golaszewski <brgl@bgdev.pl>
 
-#include <gpiod.h>
+/* Import Python.h before other headers per API documentation */
 #include <Python.h>
 
+#include <gpiod.h>
+
 struct module_const {
 	const char *name;
 	long val;
diff --git a/bindings/python/tests/gpiosim/ext.c b/bindings/python/tests/gpiosim/ext.c
index cc7bd37..1a6a238 100644
--- a/bindings/python/tests/gpiosim/ext.c
+++ b/bindings/python/tests/gpiosim/ext.c
@@ -1,9 +1,11 @@
 // SPDX-License-Identifier: LGPL-2.1-or-later
 // SPDX-FileCopyrightText: 2022 Bartosz Golaszewski <brgl@bgdev.pl>
 
-#include <gpiosim.h>
+/* Import Python.h before other headers per API documentation */
 #include <Python.h>
 
+#include <gpiosim.h>
+
 struct module_const {
 	const char *name;
 	long val;
diff --git a/bindings/python/tests/system/ext.c b/bindings/python/tests/system/ext.c
index 8b307f6..88d594d 100644
--- a/bindings/python/tests/system/ext.c
+++ b/bindings/python/tests/system/ext.c
@@ -2,7 +2,9 @@
 // SPDX-FileCopyrightText: 2022 Bartosz Golaszewski <brgl@bgdev.pl>
 // SPDX-FileCopyrightText: 2024 Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
 
+/* Import Python.h before other headers per API documentation */
 #include <Python.h>
+
 #include <linux/version.h>
 #include <sys/prctl.h>
 #include <sys/utsname.h>
-- 
2.43.0