daemon: silence warning about casts for kwargs functions

[6/18] Compiling C object src/systemd/_daemon.cpython-313-x86_64-linux-gnu.so.p/_daemon.c.o
../src/systemd/_daemon.c:415:37: warning: cast between incompatible function types from ‘PyObject * (*)(PyObject *, PyObject *, PyObject *)’ {aka ‘struct _object * (*)(struct _object *, struct _object *, struct _object *)’} to ‘PyObject * (*)(PyObject *, PyObject *)’ {aka ‘struct _object * (*)(struct _object *, struct _object *)’} [-Wcast-function-type]
  415 |         { "notify",                 (PyCFunction) notify,     METH_VARARGS | METH_KEYWORDS, notify__doc__                },
      |                                     ^
../src/systemd/_daemon.c:416:37: warning: cast between incompatible function types from ‘PyObject * (*)(PyObject *, PyObject *, PyObject *)’ {aka ‘struct _object * (*)(struct _object *, struct _object *, struct _object *)’} to ‘PyObject * (*)(PyObject *, PyObject *)’ {aka ‘struct _object * (*)(struct _object *, struct _object *)’} [-Wcast-function-type]
  416 |         { "_listen_fds",            (PyCFunction) listen_fds, METH_VARARGS | METH_KEYWORDS, listen_fds__doc__            },
      |                                     ^
../src/systemd/_daemon.c:417:37: warning: cast between incompatible function types from ‘PyObject * (*)(PyObject *, PyObject *, PyObject *)’ {aka ‘struct _object * (*)(struct _object *, struct _object *, struct _object *)’} to ‘PyObject * (*)(PyObject *, PyObject *)’ {aka ‘struct _object * (*)(struct _object *, struct _object *)’} [-Wcast-function-type]
  417 |         { "_listen_fds_with_names", (PyCFunction) listen_fds_with_names,
      |                                     ^

This is a problem in the Python C API… They should have used a union type.

Author: keszybz

src/systemd/_daemon.c

@@ -410,6 +410,7 @@ static PyObject* is_socket_unix(PyObject *self _unused_, PyObject *args) {
 }
 
 
+DISABLE_WARNING_CAST_FUNCTION_TYPE;
 static PyMethodDef methods[] = {
         { "booted",                 booted,                   METH_NOARGS,                  booted__doc__                },
         { "notify",                 (PyCFunction) notify,     METH_VARARGS | METH_KEYWORDS, notify__doc__                },
@@ -424,6 +425,7 @@ static PyMethodDef methods[] = {
         { "_is_socket_unix",        is_socket_unix,           METH_VARARGS,                 is_socket_unix__doc__        },
         {}        /* Sentinel */
 };
+REENABLE_WARNING;
 
 static struct PyModuleDef module = {
         PyModuleDef_HEAD_INIT,

src/systemd/macro.h

@@ -6,6 +6,10 @@
         _Pragma("GCC diagnostic push");                                 \
         _Pragma("GCC diagnostic ignored \"-Wmissing-prototypes\"")
 
+#define DISABLE_WARNING_CAST_FUNCTION_TYPE                              \
+        _Pragma("GCC diagnostic push");                                 \
+        _Pragma("GCC diagnostic ignored \"-Wcast-function-type\"")
+
 #define REENABLE_WARNING                                                \
         _Pragma("GCC diagnostic pop")