bpo-43852: Improve tuple creation in sqlite3 (pythonGH-25421)

Author: Erlend Egeberg Aasland

Modules/_sqlite/connection.c

@@ -592,8 +592,7 @@ _pysqlite_build_py_params(sqlite3_context *context, int argc,
             goto error;
         }
 
-        PyTuple_SetItem(args, i, cur_py_value);
-
+        PyTuple_SET_ITEM(args, i, cur_py_value);
     }
 
     return args;

Modules/_sqlite/cursor.c

@@ -357,7 +357,7 @@ _pysqlite_fetch_one_row(pysqlite_Cursor* self)
         if (!converted) {
             goto error;
         }
-        PyTuple_SetItem(row, i, converted);
+        PyTuple_SET_ITEM(row, i, converted);
     }
 
     if (PyErr_Occurred())
@@ -406,7 +406,6 @@ _pysqlite_query_execute(pysqlite_Cursor* self, int multiple, PyObject* operation
     PyObject* func_args;
     PyObject* result;
     int numcols;
-    PyObject* descriptor;
     PyObject* column_name;
     sqlite_int64 lastrowid;
 
@@ -557,30 +556,24 @@ _pysqlite_query_execute(pysqlite_Cursor* self, int multiple, PyObject* operation
                 goto error;
             }
             for (i = 0; i < numcols; i++) {
-                descriptor = PyTuple_New(7);
-                if (!descriptor) {
-                    goto error;
-                }
                 const char *colname;
                 colname = sqlite3_column_name(self->statement->st, i);
                 if (colname == NULL) {
                     PyErr_NoMemory();
-                    Py_DECREF(descriptor);
                     goto error;
                 }
                 column_name = _pysqlite_build_column_name(self, colname);
                 if (column_name == NULL) {
-                    Py_DECREF(descriptor);
                     goto error;
                 }
-                PyTuple_SetItem(descriptor, 0, column_name);
-                PyTuple_SetItem(descriptor, 1, Py_NewRef(Py_None));
-                PyTuple_SetItem(descriptor, 2, Py_NewRef(Py_None));
-                PyTuple_SetItem(descriptor, 3, Py_NewRef(Py_None));
-                PyTuple_SetItem(descriptor, 4, Py_NewRef(Py_None));
-                PyTuple_SetItem(descriptor, 5, Py_NewRef(Py_None));
-                PyTuple_SetItem(descriptor, 6, Py_NewRef(Py_None));
-                PyTuple_SetItem(self->description, i, descriptor);
+                PyObject *descriptor = PyTuple_Pack(7, column_name,
+                                                    Py_None, Py_None, Py_None,
+                                                    Py_None, Py_None, Py_None);
+                Py_DECREF(column_name);
+                if (descriptor == NULL) {
+                    goto error;
+                }
+                PyTuple_SET_ITEM(self->description, i, descriptor);
             }
         }