[3.15] gh-152817: Prevent deletion of sqlite3 cursor.row_factory attr (GH-152818) (GH-156160)

(cherry picked from commit 8e96dd6)

Co-authored-by: Steve Stagg <stestagg@gmail.com>

Author: serhiy-storchaka

Lib/test/test_sqlite3/test_factory.py

@@ -156,6 +156,14 @@ def test_delete_connection_text_factory(self):
         with self.assertRaises(AttributeError):
             del self.con.text_factory
 
+    def test_delete_cursor_row_factory(self):
+        # gh-149738: deleting row_factory should raise an exception
+        cur = self.con.cursor()
+        with self.assertRaises(AttributeError):
+            del cur.row_factory
+        # Executing a query here should succeed.
+        self.assertEqual(tuple(cur.execute("select 1").fetchone()), (1,))
+
     def test_sqlite_row_index_unicode(self):
         row = self.con.execute("select 1 as \xff").fetchone()
         self.assertEqual(row["\xff"], 1)

Misc/NEWS.d/next/Library/2026-08-21-11-00-00.gh-issue-152817.Rt6mNc.rst

@@ -0,0 +1,2 @@
+:mod:`sqlite3`: Disallow removing the ``row_factory`` attribute of a cursor
+to prevent a crash on a query.

Modules/_sqlite/cursor.c

@@ -1402,13 +1402,33 @@ static struct PyMemberDef cursor_members[] =
     {"description", _Py_T_OBJECT, offsetof(pysqlite_Cursor, description), Py_READONLY},
     {"lastrowid", _Py_T_OBJECT, offsetof(pysqlite_Cursor, lastrowid), Py_READONLY},
     {"rowcount", Py_T_LONG, offsetof(pysqlite_Cursor, rowcount), Py_READONLY},
-    {"row_factory", _Py_T_OBJECT, offsetof(pysqlite_Cursor, row_factory), 0},
     {"__weaklistoffset__", Py_T_PYSSIZET, offsetof(pysqlite_Cursor, in_weakreflist), Py_READONLY},
     {NULL}
 };
 
+static PyObject *
+cursor_get_row_factory(PyObject *op, void *Py_UNUSED(closure))
+{
+    pysqlite_Cursor *self = _pysqlite_Cursor_CAST(op);
+    return Py_NewRef(self->row_factory);
+}
+
+static int
+cursor_set_row_factory(PyObject *op, PyObject *value, void *Py_UNUSED(closure))
+{
+    pysqlite_Cursor *self = _pysqlite_Cursor_CAST(op);
+    if (value == NULL) {
+        PyErr_SetString(PyExc_AttributeError,
+                        "cannot delete row_factory attribute");
+        return -1;
+    }
+    Py_XSETREF(self->row_factory, Py_NewRef(value));
+    return 0;
+}
+
 static struct PyGetSetDef cursor_getsets[] = {
     _SQLITE3_CURSOR_ARRAYSIZE_GETSETDEF
+    {"row_factory", cursor_get_row_factory, cursor_set_row_factory},
     {NULL},
 };