Issue #20440: More use of Py_SETREF.

This patch is manually crafted and contains changes that couldn't be handled
automatically.

4 files changed, 23 insertions, 40 deletions

diff --git a/Modules/_ctypes/_ctypes.c b/Modules/_ctypes/_ctypes.c
index 01fccca..5cf2b8b 100644
--- a/Modules/_ctypes/_ctypes.c
+++ b/Modules/_ctypes/_ctypes.c
@@ -2983,10 +2983,9 @@ PyCFuncPtr_set_restype(PyCFuncPtrObject *self, PyObject *ob)
                         "restype must be a type, a callable, or None");
         return -1;
     }
-    Py_XDECREF(self->checker);
     Py_INCREF(ob);
     Py_SETREF(self->restype, ob);
-    self->checker = PyObject_GetAttrString(ob, "_check_retval_");
+    Py_SETREF(self->checker, PyObject_GetAttrString(ob, "_check_retval_"));
     if (self->checker == NULL)
         PyErr_Clear();
     return 0;
diff --git a/Modules/_elementtree.c b/Modules/_elementtree.c
index 2856bac..11d1aec 100644
--- a/Modules/_elementtree.c
+++ b/Modules/_elementtree.c
@@ -935,9 +935,8 @@ element_setstate_from_attributes(ElementObject *self,
         return NULL;
     }
 
-    Py_CLEAR(self->tag);
-    self->tag = tag;
-    Py_INCREF(self->tag);
+    Py_INCREF(tag);
+    Py_SETREF(self->tag, tag);
 
     _clear_joined_ptr(&self->text);
     self->text = text ? JOIN_SET(text, PyList_CheckExact(text)) : Py_None;
@@ -980,9 +979,8 @@ element_setstate_from_attributes(ElementObject *self,
 
     /* Stash attrib. */
     if (attrib) {
-        Py_CLEAR(self->extra->attrib);
-        self->extra->attrib = attrib;
         Py_INCREF(attrib);
+        Py_SETREF(self->extra->attrib, attrib);
     }
 
     Py_RETURN_NONE;
@@ -1944,9 +1942,8 @@ element_setattro(ElementObject* self, PyObject* nameobj, PyObject* value)
         return -1;
 
     if (strcmp(name, "tag") == 0) {
-        Py_DECREF(self->tag);
-        self->tag = value;
-        Py_INCREF(self->tag);
+        Py_INCREF(value);
+        Py_SETREF(self->tag, value);
     } else if (strcmp(name, "text") == 0) {
         Py_DECREF(JOIN_OBJ(self->text));
         self->text = value;
@@ -1960,9 +1957,8 @@ element_setattro(ElementObject* self, PyObject* nameobj, PyObject* value)
             if (create_extra(self, NULL) < 0)
                 return -1;
         }
-        Py_DECREF(self->extra->attrib);
-        self->extra->attrib = value;
-        Py_INCREF(self->extra->attrib);
+        Py_INCREF(value);
+        Py_SETREF(self->extra->attrib, value);
     } else {
         PyErr_SetString(PyExc_AttributeError,
             "Can't set arbitrary attributes on Element");
@@ -2554,13 +2550,10 @@ treebuilder_handle_start(TreeBuilderObject* self, PyObject* tag,
     }
     self->index++;
 
-    Py_DECREF(this);
     Py_INCREF(node);
-    self->this = node;
-
-    Py_DECREF(self->last);
+    Py_SETREF(self->this, node);
     Py_INCREF(node);
-    self->last = node;
+    Py_SETREF(self->last, node);
 
     if (treebuilder_append_event(self, self->start_event_obj, node) < 0)
         goto error;
@@ -2633,15 +2626,12 @@ treebuilder_handle_end(TreeBuilderObject* self, PyObject* tag)
         return NULL;
     }
 
-    self->index--;
-
-    item = PyList_GET_ITEM(self->stack, self->index);
-    Py_INCREF(item);
-
-    Py_DECREF(self->last);
-
+    item = self->last;
     self->last = self->this;
-    self->this = item;
+    self->index--;
+    self->this = PyList_GET_ITEM(self->stack, self->index);
+    Py_INCREF(self->this);
+    Py_DECREF(item);
 
     if (treebuilder_append_event(self, self->end_event_obj, self->last) < 0)
         return NULL;
diff --git a/Modules/_sqlite/cursor.c b/Modules/_sqlite/cursor.c
index d909738..c0c8746 100644
--- a/Modules/_sqlite/cursor.c
+++ b/Modules/_sqlite/cursor.c
@@ -524,10 +524,10 @@ PyObject* _pysqlite_query_execute(pysqlite_Cursor* self, int multiple, PyObject*
 
     if (self->statement) {
         (void)pysqlite_statement_reset(self->statement);
-        Py_DECREF(self->statement);
     }
 
-    self->statement = (pysqlite_Statement*)pysqlite_cache_get(self->connection->statement_cache, func_args);
+    Py_SETREF(self->statement,
+              (pysqlite_Statement *)pysqlite_cache_get(self->connection->statement_cache, func_args));
     Py_DECREF(func_args);
 
     if (!self->statement) {
diff --git a/Modules/zlibmodule.c b/Modules/zlibmodule.c
index a15fdb2..d5a6e53 100644
--- a/Modules/zlibmodule.c
+++ b/Modules/zlibmodule.c
@@ -961,14 +961,11 @@ zlib_Compress_copy_impl(compobject *self)
         goto error;
     }
     Py_INCREF(self->unused_data);
+    Py_SETREF(retval->unused_data, self->unused_data);
     Py_INCREF(self->unconsumed_tail);
+    Py_SETREF(retval->unconsumed_tail, self->unconsumed_tail);
     Py_XINCREF(self->zdict);
-    Py_XDECREF(retval->unused_data);
-    Py_XDECREF(retval->unconsumed_tail);
-    Py_XDECREF(retval->zdict);
-    retval->unused_data = self->unused_data;
-    retval->unconsumed_tail = self->unconsumed_tail;
-    retval->zdict = self->zdict;
+    Py_SETREF(retval->zdict, self->zdict);
     retval->eof = self->eof;
 
     /* Mark it as being initialized */
@@ -1020,14 +1017,11 @@ zlib_Decompress_copy_impl(compobject *self)
     }
 
     Py_INCREF(self->unused_data);
+    Py_SETREF(retval->unused_data, self->unused_data);
     Py_INCREF(self->unconsumed_tail);
+    Py_SETREF(retval->unconsumed_tail, self->unconsumed_tail);
     Py_XINCREF(self->zdict);
-    Py_XDECREF(retval->unused_data);
-    Py_XDECREF(retval->unconsumed_tail);
-    Py_XDECREF(retval->zdict);
-    retval->unused_data = self->unused_data;
-    retval->unconsumed_tail = self->unconsumed_tail;
-    retval->zdict = self->zdict;
+    Py_SETREF(retval->zdict, self->zdict);
     retval->eof = self->eof;
 
     /* Mark it as being initialized */