Use Py_CLEAR instead of in-place DECREF/XDECREF or custom macros, for

tp_clear methods.

Modules/_csv.c

@@ -828,12 +828,9 @@ Reader_traverse(ReaderObj *self, visitproc visit, void *arg)
 static int
 Reader_clear(ReaderObj *self)
 {
-        Py_XDECREF(self->dialect);
-        Py_XDECREF(self->input_iter);
-        Py_XDECREF(self->fields);
-        self->dialect = NULL;
-        self->input_iter = NULL;
-        self->fields = NULL;
+	Py_CLEAR(self->dialect);
+	Py_CLEAR(self->input_iter);
+	Py_CLEAR(self->fields);
 	return 0;
 }
 
@@ -1260,10 +1257,8 @@ Writer_traverse(WriterObj *self, visitproc visit, void *arg)
 static int
 Writer_clear(WriterObj *self)
 {
-        Py_XDECREF(self->dialect);
-        Py_XDECREF(self->writeline);
-	self->dialect = NULL;
-	self->writeline = NULL;
+	Py_CLEAR(self->dialect);
+	Py_CLEAR(self->writeline);
 	return 0;
 }
 

Modules/cPickle.c

@@ -2931,16 +2931,14 @@ Pickler_traverse(Picklerobject *self, visitproc visit, void *arg)
 static int
 Pickler_clear(Picklerobject *self)
 {
-#define CLEAR(SLOT) Py_XDECREF(SLOT); SLOT = NULL;
-	CLEAR(self->write);
-	CLEAR(self->memo);
-	CLEAR(self->fast_memo);
-	CLEAR(self->arg);
-	CLEAR(self->file);
-	CLEAR(self->pers_func);
-	CLEAR(self->inst_pers_func);
-	CLEAR(self->dispatch_table);
-#undef CLEAR
+	Py_CLEAR(self->write);
+	Py_CLEAR(self->memo);
+	Py_CLEAR(self->fast_memo);
+	Py_CLEAR(self->arg);
+	Py_CLEAR(self->file);
+	Py_CLEAR(self->pers_func);
+	Py_CLEAR(self->inst_pers_func);
+	Py_CLEAR(self->dispatch_table);
 	return 0;
 }
 
@@ -5284,17 +5282,15 @@ Unpickler_traverse(Unpicklerobject *self, visitproc visit, void *arg)
 static int
 Unpickler_clear(Unpicklerobject *self)
 {
-#define CLEAR(SLOT) Py_XDECREF(SLOT); SLOT = NULL
-	CLEAR(self->readline);
-	CLEAR(self->read);
-	CLEAR(self->file);
-	CLEAR(self->memo);
-	CLEAR(self->stack);
-	CLEAR(self->pers_func);
-	CLEAR(self->arg);
-	CLEAR(self->last_string);
-	CLEAR(self->find_class);
-#undef CLEAR
+	Py_CLEAR(self->readline);
+	Py_CLEAR(self->read);
+	Py_CLEAR(self->file);
+	Py_CLEAR(self->memo);
+	Py_CLEAR(self->stack);
+	Py_CLEAR(self->pers_func);
+	Py_CLEAR(self->arg);
+	Py_CLEAR(self->last_string);
+	Py_CLEAR(self->find_class);
 	return 0;
 }
 

Modules/collectionsmodule.c

@@ -1236,10 +1236,7 @@ defdict_traverse(PyObject *self, visitproc visit, void *arg)
 static int
 defdict_tp_clear(defdictobject *dd)
 {
-	if (dd->default_factory != NULL) {
-		Py_DECREF(dd->default_factory);
-		dd->default_factory = NULL;
-	}
+	Py_CLEAR(dd->default_factory);
 	return PyDict_Type.tp_clear((PyObject *)dd);
 }
 

Modules/pyexpat.c

@@ -1669,8 +1669,7 @@ static int
 xmlparse_clear(xmlparseobject *op)
 {
     clear_handlers(op, 0);
-    Py_XDECREF(op->intern);
-    op->intern = 0;
+    Py_CLEAR(op->intern);
     return 0;
 }
 #endif

Objects/cellobject.c

@@ -81,8 +81,7 @@ cell_traverse(PyCellObject *op, visitproc visit, void *arg)
 static int
 cell_clear(PyCellObject *op)
 {
-	Py_XDECREF(op->ob_ref);
-	op->ob_ref = NULL;
+	Py_CLEAR(op->ob_ref);
 	return 0;
 }
 

Objects/funcobject.c

@@ -655,9 +655,7 @@ cm_traverse(classmethod *cm, visitproc visit, void *arg)
 static int
 cm_clear(classmethod *cm)
 {
-	Py_XDECREF(cm->cm_callable);
-	cm->cm_callable = NULL;
-
+	Py_CLEAR(cm->cm_callable);
 	return 0;
 }
 

Objects/typeobject.c

@@ -559,8 +559,8 @@ clear_slots(PyTypeObject *type, PyObject *self)
 			char *addr = (char *)self + mp->offset;
 			PyObject *obj = *(PyObject **)addr;
 			if (obj != NULL) {
-				Py_DECREF(obj);
 				*(PyObject **)addr = NULL;
+				Py_DECREF(obj);
 			}
 		}
 	}
@@ -2236,13 +2236,6 @@ type_clear(PyTypeObject *type)
 	   for heaptypes. */
 	assert(type->tp_flags & Py_TPFLAGS_HEAPTYPE);
 
-#define CLEAR(SLOT) \
-	if (SLOT) { \
-		tmp = (PyObject *)(SLOT); \
-		SLOT = NULL; \
-		Py_DECREF(tmp); \
-	}
-
 	/* The only field we need to clear is tp_mro, which is part of a
 	   hard cycle (its first element is the class itself) that won't
 	   be broken otherwise (it's a tuple and tuples don't have a
@@ -2268,9 +2261,7 @@ type_clear(PyTypeObject *type)
 	       A tuple of strings can't be part of a cycle.
 	*/
 
-	CLEAR(type->tp_mro);
-
-#undef CLEAR
+	Py_CLEAR(type->tp_mro);
 
 	return 0;
 }

Python/traceback.c

@@ -53,10 +53,8 @@ tb_traverse(PyTracebackObject *tb, visitproc visit, void *arg)
 static void
 tb_clear(PyTracebackObject *tb)
 {
-	Py_XDECREF(tb->tb_next);
-	Py_XDECREF(tb->tb_frame);
-	tb->tb_next = NULL;
-	tb->tb_frame = NULL;
+	Py_CLEAR(tb->tb_next);
+	Py_CLEAR(tb->tb_frame);
 }
 
 PyTypeObject PyTraceBack_Type = {