gh-82616: Add Py_IS_TYPE_SIGNED() macro (#93178)

_posixsubprocess: add a static assertion to ensure that the pid_t
type is signed.

Replace _Py_IntegralTypeSigned() with _Py_IS_TYPE_SIGNED().

2 files changed, 18 insertions, 1 deletions

diff --git a/Modules/_posixsubprocess.c b/Modules/_posixsubprocess.c
index 9132f13..44e60d7 100644
--- a/Modules/_posixsubprocess.c
+++ b/Modules/_posixsubprocess.c
@@ -612,8 +612,10 @@ child_exec(char *const exec_array[],
 #endif
 
 #ifdef HAVE_SETPGID
-    if (pgid_to_set >= 0)
+    static_assert(_Py_IS_TYPE_SIGNED(pid_t), "pid_t is unsigned");
+    if (pgid_to_set >= 0) {
         POSIX_CALL(setpgid(0, pgid_to_set));
+    }
 #endif
 
 #ifdef HAVE_SETGROUPS
diff --git a/Modules/_testcapimodule.c b/Modules/_testcapimodule.c
index 37f4ded..ac0c96a 100644
--- a/Modules/_testcapimodule.c
+++ b/Modules/_testcapimodule.c
@@ -5858,6 +5858,20 @@ settrace_to_record(PyObject *self, PyObject *list)
     Py_RETURN_NONE;
 }
 
+static PyObject *
+test_macros(PyObject *self, PyObject *Py_UNUSED(args))
+{
+    // Py_MIN(), Py_MAX()
+    assert(Py_MIN(5, 11) == 5);
+    assert(Py_MAX(5, 11) == 11);
+
+    // _Py_IS_TYPE_SIGNED()
+    assert(_Py_IS_TYPE_SIGNED(int));
+    assert(!_Py_IS_TYPE_SIGNED(unsigned int));
+
+    Py_RETURN_NONE;
+}
+
 static PyObject *negative_dictoffset(PyObject *, PyObject *);
 static PyObject *test_buildvalue_issue38913(PyObject *, PyObject *);
 static PyObject *getargs_s_hash_int(PyObject *, PyObject *, PyObject*);
@@ -6149,6 +6163,7 @@ static PyMethodDef TestMethods[] = {
     {"get_feature_macros", get_feature_macros, METH_NOARGS, NULL},
     {"test_code_api", test_code_api, METH_NOARGS, NULL},
     {"settrace_to_record", settrace_to_record, METH_O, NULL},
+    {"test_macros", test_macros, METH_NOARGS, NULL},
     {NULL, NULL} /* sentinel */
 };