Fix issue with client-server out-of-sync in case of permission error (#579)

Author: olesz

requirements-dev.txt

@@ -2,4 +2,5 @@ pytest
 pytest-timeout
 python-dateutil
 tox
+parameterized
 #kerberos

vertica_python/tests/integration_tests/base.py

@@ -93,6 +93,17 @@ def _connect(cls):
         """
         return connect(**cls._conn_info)
 
+    @classmethod
+    def _connect_user_pass(cls, user: str, password: str):
+        """Connects to vertica with an overridden user/pass.
+
+        :return: a connection to vertica.
+        """
+        conn_info = cls._conn_info.copy()
+        conn_info['user'] = user
+        conn_info['password'] = password
+        return connect(**conn_info)
+
     @classmethod
     def _get_node_num(cls):
         """Executes a query to get the number of nodes in the database

vertica_python/tests/integration_tests/test_cursor.py

@@ -1193,6 +1193,8 @@ def setUpClass(cls):
     def setUp(self):
         super(PreparedStatementTestCase, self).setUp()
         self._table = 'preparedstmt_test'
+        self._user = 'test_user'
+        self._password = 'TestPassword123'
         with self._connect() as conn:
             cur = conn.cursor()
             cur.execute("DROP TABLE IF EXISTS {0}".format(self._table))
@@ -1472,3 +1474,27 @@ def test_bind_udtype(self):
 
             self.assertEqual(cur.description[0].display_size, 10000)
             self.assertEqual(cur.description[1].display_size, 1000)
+
+    def test_multiple_permission_error(self):
+        with self._connect() as conn:
+            try:
+                cur = conn.cursor()
+                cur.execute("CREATE TABLE {} (id INT)"
+                            .format(self._table))
+
+                try:
+                    cur.execute("CREATE USER {} IDENTIFIED BY '{}'".format(self._user, self._password), use_prepared_statements=False)
+                except errors.QueryError:
+                    pass  # User already exists
+                conn.commit()
+
+                with self._connect_user_pass(self._user, self._password) as conn_2:
+                    cur_2 = conn_2.cursor()
+                    for i in range(1, 5):
+                        with pytest.raises(errors.DatabaseError, match='Permission denied for relation {}'.format(self._table)):
+                            cur_2.execute("SELECT * FROM {} LIMIT 1".format(self._table))
+            finally:
+                try:
+                    cur.execute("DROP USER {}".format(self._user))
+                except errors.QueryError:
+                    pass  # User did not exist

vertica_python/vertica/cursor.py

@@ -945,6 +945,10 @@ def _error_handler(self, msg: BackendMessage) -> NoReturn:
         self.connection.write(messages.Sync())
         raise errors.QueryError.from_error_response(msg, self.operation)
 
+    def _prepared_statement_error_handler(self, msg: BackendMessage) -> NoReturn:
+        self._message = msg
+        raise errors.DatabaseError(msg.error_message())
+
     def _prepare(self, query: str) -> None:
         """
         Send the query to be prepared to the server. The server will parse the
@@ -1024,7 +1028,7 @@ def _execute_prepared_statement(self, list_of_parameter_values: Sequence[Any]) -
         self.connection.write(messages.Flush())
 
         # Read expected message: BindComplete
-        self.connection.read_expected_message(messages.BindComplete)
+        self.connection.read_expected_message(messages.BindComplete, self._prepared_statement_error_handler)
 
         self._message = self.connection.read_message()
         if isinstance(self._message, messages.ErrorResponse):