pythongh-69093: Don't allow instantiation of sqlite3.Blob objects

Author: Erlend E. Aasland

Lib/test/test_sqlite3/test_dbapi.py

@@ -356,6 +356,7 @@ def test_shared_cache_deprecated(self):
     def test_disallow_instantiation(self):
         cx = sqlite.connect(":memory:")
         check_disallow_instantiation(self, type(cx("select 1")))
+        check_disallow_instantiation(self, sqlite.Blob)
 
     def test_complete_statement(self):
         self.assertFalse(sqlite.complete_statement("select t"))

Modules/_sqlite/blob.c

@@ -334,7 +334,7 @@ static PyType_Spec blob_spec = {
     .name = MODULE_NAME ".Blob",
     .basicsize = sizeof(pysqlite_Blob),
     .flags = (Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC |
-              Py_TPFLAGS_IMMUTABLETYPE),
+              Py_TPFLAGS_IMMUTABLETYPE | Py_TPFLAGS_DISALLOW_INSTANTIATION),
     .slots = blob_slots,
 };