Issue #21975: Fixed crash when using uninitialized sqlite3.Row (in particular

when unpickling pickled sqlite3.Row).  sqlite3.Row is now initialized in the
__new__() method.

Misc/NEWS

@@ -112,6 +112,10 @@ Core and Builtins
 Library
 -------
 
+- Issue #21975: Fixed crash when using uninitialized sqlite3.Row (in particular
+  when unpickling pickled sqlite3.Row).  sqlite3.Row is now initialized in the
+  __new__() method.
+
 - Issue #20170: Convert posixmodule to use Argument Clinic.
 
 - Issue #21539: Add a *exists_ok* argument to `Pathlib.mkdir()` to mimic

Modules/_sqlite/row.c

@@ -32,35 +32,41 @@ void pysqlite_row_dealloc(pysqlite_Row* self)
     Py_TYPE(self)->tp_free((PyObject*)self);
 }
 
-int pysqlite_row_init(pysqlite_Row* self, PyObject* args, PyObject* kwargs)
+static PyObject *
+pysqlite_row_new(PyTypeObject *type, PyObject *args, PyObject *kwargs)
 {
+    pysqlite_Row *self;
     PyObject* data;
     pysqlite_Cursor* cursor;
 
-    self->data = 0;
-    self->description = 0;
+    assert(type != NULL && type->tp_alloc != NULL);
 
-    if (!PyArg_ParseTuple(args, "OO", &cursor, &data)) {
-        return -1;
-    }
+    if (!_PyArg_NoKeywords("Row()", kwargs))
+        return NULL;
+    if (!PyArg_ParseTuple(args, "OO", &cursor, &data))
+        return NULL;
 
     if (!PyObject_IsInstance((PyObject*)cursor, (PyObject*)&pysqlite_CursorType)) {
         PyErr_SetString(PyExc_TypeError, "instance of cursor required for first argument");
-        return -1;
+        return NULL;
     }
 
     if (!PyTuple_Check(data)) {
         PyErr_SetString(PyExc_TypeError, "tuple required for second argument");
-        return -1;
+        return NULL;
     }
 
+    self = (pysqlite_Row *) type->tp_alloc(type, 0);
+    if (self == NULL)
+        return NULL;
+
     Py_INCREF(data);
     self->data = data;
 
     Py_INCREF(cursor->description);
     self->description = cursor->description;
 
-    return 0;
+    return (PyObject *) self;
 }
 
 PyObject* pysqlite_row_item(pysqlite_Row* self, Py_ssize_t idx)
@@ -260,7 +266,7 @@ PyTypeObject pysqlite_RowType = {
         0,                                              /* tp_descr_get */
         0,                                              /* tp_descr_set */
         0,                                              /* tp_dictoffset */
-        (initproc)pysqlite_row_init,                    /* tp_init */
+        0,                                              /* tp_init */
         0,                                              /* tp_alloc */
         0,                                              /* tp_new */
         0                                               /* tp_free */
@@ -268,7 +274,7 @@ PyTypeObject pysqlite_RowType = {
 
 extern int pysqlite_row_setup_types(void)
 {
-    pysqlite_RowType.tp_new = PyType_GenericNew;
+    pysqlite_RowType.tp_new = pysqlite_row_new;
     pysqlite_RowType.tp_as_mapping = &pysqlite_row_as_mapping;
     pysqlite_RowType.tp_as_sequence = &pysqlite_row_as_sequence;
     return PyType_Ready(&pysqlite_RowType);