[3.12] gh-116404: Handle errors correctly in wait_helper in posixmodule (GH-116405) (#116406)

gh-116404: Handle errors correctly in `wait_helper` in `posixmodule` (GH-116405)
(cherry picked from commit 22ccf13)

Co-authored-by: Nikita Sobolev <[email protected]>

Author: miss-islington

Modules/posixmodule.c

@@ -9245,36 +9245,39 @@ wait_helper(PyObject *module, pid_t pid, int status, struct rusage *ru)
     if (!result)
         return NULL;
 
+    int pos = 0;
+
 #ifndef doubletime
 #define doubletime(TV) ((double)(TV).tv_sec + (TV).tv_usec * 0.000001)
 #endif
 
-    PyStructSequence_SET_ITEM(result, 0,
-                              PyFloat_FromDouble(doubletime(ru->ru_utime)));
-    PyStructSequence_SET_ITEM(result, 1,
-                              PyFloat_FromDouble(doubletime(ru->ru_stime)));
-#define SET_INT(result, index, value)\
-        PyStructSequence_SET_ITEM(result, index, PyLong_FromLong(value))
-    SET_INT(result, 2, ru->ru_maxrss);
-    SET_INT(result, 3, ru->ru_ixrss);
-    SET_INT(result, 4, ru->ru_idrss);
-    SET_INT(result, 5, ru->ru_isrss);
-    SET_INT(result, 6, ru->ru_minflt);
-    SET_INT(result, 7, ru->ru_majflt);
-    SET_INT(result, 8, ru->ru_nswap);
-    SET_INT(result, 9, ru->ru_inblock);
-    SET_INT(result, 10, ru->ru_oublock);
-    SET_INT(result, 11, ru->ru_msgsnd);
-    SET_INT(result, 12, ru->ru_msgrcv);
-    SET_INT(result, 13, ru->ru_nsignals);
-    SET_INT(result, 14, ru->ru_nvcsw);
-    SET_INT(result, 15, ru->ru_nivcsw);
-#undef SET_INT
-
-    if (PyErr_Occurred()) {
-        Py_DECREF(result);
-        return NULL;
-    }
+#define SET_RESULT(CALL)                                     \
+    do {                                                     \
+        PyObject *item = (CALL);                             \
+        if (item == NULL) {                                  \
+            Py_DECREF(result);                               \
+            return NULL;                                     \
+        }                                                    \
+        PyStructSequence_SET_ITEM(result, pos++, item);      \
+    } while(0)
+
+    SET_RESULT(PyFloat_FromDouble(doubletime(ru->ru_utime)));
+    SET_RESULT(PyFloat_FromDouble(doubletime(ru->ru_stime)));
+    SET_RESULT(PyLong_FromLong(ru->ru_maxrss));
+    SET_RESULT(PyLong_FromLong(ru->ru_ixrss));
+    SET_RESULT(PyLong_FromLong(ru->ru_idrss));
+    SET_RESULT(PyLong_FromLong(ru->ru_isrss));
+    SET_RESULT(PyLong_FromLong(ru->ru_minflt));
+    SET_RESULT(PyLong_FromLong(ru->ru_majflt));
+    SET_RESULT(PyLong_FromLong(ru->ru_nswap));
+    SET_RESULT(PyLong_FromLong(ru->ru_inblock));
+    SET_RESULT(PyLong_FromLong(ru->ru_oublock));
+    SET_RESULT(PyLong_FromLong(ru->ru_msgsnd));
+    SET_RESULT(PyLong_FromLong(ru->ru_msgrcv));
+    SET_RESULT(PyLong_FromLong(ru->ru_nsignals));
+    SET_RESULT(PyLong_FromLong(ru->ru_nvcsw));
+    SET_RESULT(PyLong_FromLong(ru->ru_nivcsw));
+#undef SET_RESULT
 
     return Py_BuildValue("NiN", PyLong_FromPid(pid), status, result);
 }