bpo-45512: Raise sqlite3.Connection.__init__ is called with bad isolation level

Author: Erlend E. Aasland

Lib/test/test_sqlite3/test_dbapi.py

@@ -48,8 +48,8 @@ def managed_connect(*args, in_mem=False, **kwargs):
 
 
 # Helper for temporary memory databases
-def memory_database():
-    cx = sqlite.connect(":memory:")
+def memory_database(*args, **kwargs):
+    cx = sqlite.connect(":memory:", *args, **kwargs)
     return contextlib.closing(cx)
 
 
@@ -547,6 +547,14 @@ def test_connection_bad_reinit(self):
                                    cx.executemany, "insert into t values(?)",
                                    ((v,) for v in range(3)))
 
+    def test_connection_init_bad_isolation_level(self):
+        msg = (
+            "isolation_level string must be '', 'DEFERRED', 'IMMEDIATE', or "
+            "'EXCLUSIVE'"
+        )
+        with self.assertRaisesRegex(ValueError, msg):
+            memory_database(isolation_level="BOGUS")
+
 
 class UninitialisedConnectionTests(unittest.TestCase):
     def setUp(self):

Modules/_sqlite/connection.c

@@ -129,6 +129,9 @@ get_begin_statement(const char *level)
             return begin_statements[i];
         }
     }
+    PyErr_SetString(PyExc_ValueError,
+                    "isolation_level string must be '', 'DEFERRED', "
+                    "'IMMEDIATE', or 'EXCLUSIVE'");
     return NULL;
 }
 
@@ -1399,9 +1402,6 @@ pysqlite_connection_set_isolation_level(pysqlite_Connection* self, PyObject* iso
         }
         const char *stmt = get_begin_statement(cstr_level);
         if (stmt == NULL) {
-            PyErr_SetString(PyExc_ValueError,
-                            "isolation_level string must be '', 'DEFERRED', "
-                            "'IMMEDIATE', or 'EXCLUSIVE'");
             return -1;
         }
         self->begin_statement = stmt;