bpo-35059: Cleanup usage of Python macros (GH-10648)

Don't pass complex expressions but regular variables to Python
macros.

* _datetimemodule.c: split single large "if" into two "if"
  in date_new(), time_new() and datetime_new().
* _pickle.c, load_extension(): flatten complex "if" expression into
  more regular C code.
* _ssl.c: addbool() now uses a temporary bool_obj to only evaluate
  the value once.
* weakrefobject.c: replace "Py_INCREF(result = proxy);"
  with "result = proxy; Py_INCREF(result);"

Modules/_datetimemodule.c

@@ -2798,8 +2798,9 @@ date_new(PyTypeObject *type, PyObject *args, PyObject *kw)
     int day;
 
     /* Check for invocation from pickle with __getstate__ state */
-    if (PyTuple_GET_SIZE(args) == 1 &&
-        PyBytes_Check(state = PyTuple_GET_ITEM(args, 0)) &&
+    if (PyTuple_GET_SIZE(args) == 1) {
+        state = PyTuple_GET_ITEM(args, 0);
+        if (PyBytes_Check(state) &&
             PyBytes_GET_SIZE(state) == _PyDateTime_DATE_DATASIZE &&
             MONTH_IS_SANE(PyBytes_AS_STRING(state)[2]))
         {
@@ -2813,6 +2814,7 @@ date_new(PyTypeObject *type, PyObject *args, PyObject *kw)
             }
             return (PyObject *)me;
         }
+    }
 
     if (PyArg_ParseTupleAndKeywords(args, kw, "iii", date_kws,
                                     &year, &month, &day)) {
@@ -3913,8 +3915,10 @@ time_new(PyTypeObject *type, PyObject *args, PyObject *kw)
 
     /* Check for invocation from pickle with __getstate__ state */
     if (PyTuple_GET_SIZE(args) >= 1 &&
-        PyTuple_GET_SIZE(args) <= 2 &&
-        PyBytes_Check(state = PyTuple_GET_ITEM(args, 0)) &&
+        PyTuple_GET_SIZE(args) <= 2)
+    {
+        state = PyTuple_GET_ITEM(args, 0);
+        if (PyBytes_Check(state) &&
             PyBytes_GET_SIZE(state) == _PyDateTime_TIME_DATASIZE &&
             (0x7F & ((unsigned char) (PyBytes_AS_STRING(state)[0]))) < 24)
         {
@@ -3951,6 +3955,7 @@ time_new(PyTypeObject *type, PyObject *args, PyObject *kw)
             }
             return (PyObject *)me;
         }
+    }
 
     if (PyArg_ParseTupleAndKeywords(args, kw, "|iiiiO$i", time_kws,
                                     &hour, &minute, &second, &usecond,
@@ -4552,8 +4557,10 @@ datetime_new(PyTypeObject *type, PyObject *args, PyObject *kw)
 
     /* Check for invocation from pickle with __getstate__ state */
     if (PyTuple_GET_SIZE(args) >= 1 &&
-        PyTuple_GET_SIZE(args) <= 2 &&
-        PyBytes_Check(state = PyTuple_GET_ITEM(args, 0)) &&
+        PyTuple_GET_SIZE(args) <= 2)
+    {
+        state = PyTuple_GET_ITEM(args, 0);
+        if (PyBytes_Check(state) &&
             PyBytes_GET_SIZE(state) == _PyDateTime_DATETIME_DATASIZE &&
             MONTH_IS_SANE(PyBytes_AS_STRING(state)[2] & 0x7F))
         {
@@ -4590,6 +4597,7 @@ datetime_new(PyTypeObject *type, PyObject *args, PyObject *kw)
             }
             return (PyObject *)me;
         }
+    }
 
     if (PyArg_ParseTupleAndKeywords(args, kw, "iii|iiiiO$i", datetime_kws,
                                     &year, &month, &day, &hour, &minute,

Modules/_pickle.c

@@ -5858,14 +5858,20 @@ load_extension(UnpicklerObject *self, int nbytes)
     /* Since the extension registry is manipulable via Python code,
      * confirm that pair is really a 2-tuple of strings.
      */
-    if (!PyTuple_Check(pair) || PyTuple_Size(pair) != 2 ||
-        !PyUnicode_Check(module_name = PyTuple_GET_ITEM(pair, 0)) ||
-        !PyUnicode_Check(class_name = PyTuple_GET_ITEM(pair, 1))) {
-        Py_DECREF(py_code);
-        PyErr_Format(PyExc_ValueError, "_inverted_registry[%ld] "
-                     "isn't a 2-tuple of strings", code);
-        return -1;
+    if (!PyTuple_Check(pair) || PyTuple_Size(pair) != 2) {
+        goto error;
     }
+
+    module_name = PyTuple_GET_ITEM(pair, 0);
+    if (!PyUnicode_Check(module_name)) {
+        goto error;
+    }
+
+    class_name = PyTuple_GET_ITEM(pair, 1);
+    if (!PyUnicode_Check(class_name)) {
+        goto error;
+    }
+
     /* Load the object. */
     obj = find_class(self, module_name, class_name);
     if (obj == NULL) {
@@ -5881,6 +5887,12 @@ load_extension(UnpicklerObject *self, int nbytes)
     }
     PDATA_PUSH(self->stack, obj, -1);
     return 0;
+
+error:
+    Py_DECREF(py_code);
+    PyErr_Format(PyExc_ValueError, "_inverted_registry[%ld] "
+                 "isn't a 2-tuple of strings", code);
+    return -1;
 }
 
 static int

Modules/_ssl.c

@@ -5983,9 +5983,12 @@ PyInit__ssl(void)
     PyModule_AddIntConstant(m, "PROTO_TLSv1_2", PY_PROTO_TLSv1_2);
     PyModule_AddIntConstant(m, "PROTO_TLSv1_3", PY_PROTO_TLSv1_3);
 
-#define addbool(m, v, b) \
-    Py_INCREF((b) ? Py_True : Py_False); \
-    PyModule_AddObject((m), (v), (b) ? Py_True : Py_False);
+#define addbool(m, key, value) \
+    do { \
+        PyObject *bool_obj = (value) ? Py_True : Py_False; \
+        Py_INCREF(bool_obj); \
+        PyModule_AddObject((m), (key), bool_obj); \
+    } while (0)
 
 #if HAVE_SNI
     addbool(m, "HAS_SNI", 1);

Objects/weakrefobject.c

@@ -833,7 +833,8 @@ PyWeakref_NewProxy(PyObject *ob, PyObject *callback)
                        to avoid violating the invariants of the list
                        of weakrefs for ob. */
                     Py_DECREF(result);
-                    Py_INCREF(result = proxy);
+                    result = proxy;
+                    Py_INCREF(result);
                     goto skip_insert;
                 }
                 prev = ref;