bpo-44087: Disallow instantiation of sqlite3.Statement (GH-26567)

Author: Erlend Egeberg Aasland

Lib/sqlite3/test/dbapi.py

@@ -26,6 +26,7 @@
 import threading
 import unittest
 
+from test.support import check_disallow_instantiation
 from test.support.os_helper import TESTFN, unlink
 from test.support import threading_helper
 
@@ -105,6 +106,10 @@ def test_shared_cache_deprecated(self):
                 sqlite.enable_shared_cache(enable)
             self.assertIn("dbapi.py", cm.filename)
 
+    def test_disallow_instantiation(self):
+        cx = sqlite.connect(":memory:")
+        check_disallow_instantiation(self, type(cx("select 1")))
+
 
 class ConnectionTests(unittest.TestCase):
 

Modules/_sqlite/statement.c

@@ -503,7 +503,7 @@ static PyType_Spec stmt_spec = {
     .name = MODULE_NAME ".Statement",
     .basicsize = sizeof(pysqlite_Statement),
     .flags = (Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC |
-              Py_TPFLAGS_IMMUTABLETYPE),
+              Py_TPFLAGS_IMMUTABLETYPE | Py_TPFLAGS_DISALLOW_INSTANTIATION),
     .slots = stmt_slots,
 };