Fixed. when mysql fetch result None crash

[Lupino]

when mysql fetch result is None getitem crash

    item = self.rowproxy[index]
TypeError: 'NoneType' object has no attribute '__getitem__'

[zzzeek]

hi there -

row.fetchone() will never be None, and if it is, that's a bug elsewhere. silently skipping here will just cause more failures.

can you please illustrate a complete test case that shows how this value becomes None?

[Lupino]

error cause on mysql version 5.7.18

Python 2.7.13 (default, Dec 18 2016, 07:03:39)
[GCC 4.2.1 Compatible Apple LLVM 8.0.0 (clang-800.0.42.1)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> import sqlalchemy
>>> engine = sqlalchemy.create_engine('mysql://root:@localhost/traffic?charset=utf8')
>>> conn = engine.connect()
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/Users/lmj/repo/nupic/venv-test/lib/python2.7/site-packages/sqlalchemy/engine/base.py", line 2091, in connect
    return self._connection_cls(self, **kwargs)
  File "/Users/lmj/repo/nupic/venv-test/lib/python2.7/site-packages/sqlalchemy/engine/base.py", line 90, in __init__
    if connection is not None else engine.raw_connection()
  File "/Users/lmj/repo/nupic/venv-test/lib/python2.7/site-packages/sqlalchemy/engine/base.py", line 2177, in raw_connection
    self.pool.unique_connection, _connection)
  File "/Users/lmj/repo/nupic/venv-test/lib/python2.7/site-packages/sqlalchemy/engine/base.py", line 2147, in _wrap_pool_connect
    return fn()
  File "/Users/lmj/repo/nupic/venv-test/lib/python2.7/site-packages/sqlalchemy/pool.py", line 328, in unique_connection
    return _ConnectionFairy._checkout(self)
  File "/Users/lmj/repo/nupic/venv-test/lib/python2.7/site-packages/sqlalchemy/pool.py", line 766, in _checkout
    fairy = _ConnectionRecord.checkout(pool)
  File "/Users/lmj/repo/nupic/venv-test/lib/python2.7/site-packages/sqlalchemy/pool.py", line 516, in checkout
    rec = pool._do_get()
  File "/Users/lmj/repo/nupic/venv-test/lib/python2.7/site-packages/sqlalchemy/pool.py", line 1138, in _do_get
    self._dec_overflow()
  File "/Users/lmj/repo/nupic/venv-test/lib/python2.7/site-packages/sqlalchemy/util/langhelpers.py", line 66, in __exit__
    compat.reraise(exc_type, exc_value, exc_tb)
  File "/Users/lmj/repo/nupic/venv-test/lib/python2.7/site-packages/sqlalchemy/pool.py", line 1135, in _do_get
    return self._create_connection()
  File "/Users/lmj/repo/nupic/venv-test/lib/python2.7/site-packages/sqlalchemy/pool.py", line 333, in _create_connection
    return _ConnectionRecord(self)
  File "/Users/lmj/repo/nupic/venv-test/lib/python2.7/site-packages/sqlalchemy/pool.py", line 461, in __init__
    self.__connect(first_connect_check=True)
  File "/Users/lmj/repo/nupic/venv-test/lib/python2.7/site-packages/sqlalchemy/pool.py", line 661, in __connect
    exec_once(self.connection, self)
  File "/Users/lmj/repo/nupic/venv-test/lib/python2.7/site-packages/sqlalchemy/event/attr.py", line 246, in exec_once
    self(*args, **kw)
  File "/Users/lmj/repo/nupic/venv-test/lib/python2.7/site-packages/sqlalchemy/event/attr.py", line 256, in __call__
    fn(*args, **kw)
  File "/Users/lmj/repo/nupic/venv-test/lib/python2.7/site-packages/sqlalchemy/util/langhelpers.py", line 1331, in go
    return once_fn(*arg, **kw)
  File "/Users/lmj/repo/nupic/venv-test/lib/python2.7/site-packages/sqlalchemy/engine/strategies.py", line 181, in first_connect
    dialect.initialize(c)
  File "/Users/lmj/repo/nupic/venv-test/lib/python2.7/site-packages/sqlalchemy/dialects/mysql/base.py", line 1698, in initialize
    self._detect_ansiquotes(connection)
  File "/Users/lmj/repo/nupic/venv-test/lib/python2.7/site-packages/sqlalchemy/dialects/mysql/base.py", line 1975, in _detect_ansiquotes
    mode = row[1] or ''
  File "/Users/lmj/repo/nupic/venv-test/lib/python2.7/site-packages/sqlalchemy/dialects/mysql/base.py", line 2062, in __getitem__
    item = self.rowproxy[index]
TypeError: 'NoneType' object has no attribute '__getitem__'
>>>

[Lupino]

Fixed. the _compat_fist and test the _compat_fetchone

mysql> select * from `instance_status_history`;
Empty set (0.00 sec)

mysql>

Python 2.7.13 (default, Dec 18 2016, 07:03:39)
[GCC 4.2.1 Compatible Apple LLVM 8.0.0 (clang-800.0.42.1)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> import sqlalchemy
>>> engine = sqlalchemy.create_engine('mysql://root:@localhost/traffic?charset=utf8')
>>> conn = engine.connect()
>>> rp = conn.execute('select * from `instance_status_history`')
>>> row = rp.dialect._compat_fetchone(rp)
>>> row[1]
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/Users/lmj/repo/nupic/venv-test/lib/python2.7/site-packages/sqlalchemy/dialects/mysql/base.py", line 2064, in __getitem__
    item = self.rowproxy[index]
TypeError: 'NoneType' object has no attribute '__getitem__'
>>>

[zzzeek]

mmmm still need to see what MySQL Python version you have, run this:

python -c "import MySQLdb; print(MySQLdb.__version__)"

Also go onto your database and show me the output of this:

MariaDB [(none)]> show variables like 'sql_mode';
+---------------+--------------------------------------------+
| Variable_name | Value                                      |
+---------------+--------------------------------------------+
| sql_mode      | NO_AUTO_CREATE_USER,NO_ENGINE_SUBSTITUTION |
+---------------+--------------------------------------------+
1 row in set (0.00 sec)

"sql_mode" is always present, if something weird is going on on your database where this is not coming back, we have to fix this elsewhere (e.g. we should not be calling _compat_first()).

[Lupino]

$ python -c "import MySQLdb; print(MySQLdb.__version__)"
1.2.5

$ mysql -u root
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 4269
Server version: 5.7.18 Homebrew

Copyright (c) 2000, 2017, Oracle and/or its affiliates. All rights reserved.

Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

mysql> show variables like 'sql_mode';
Empty set (0.00 sec)

mysql>

[zzzeek]

OK. can you show me the output of "SHOW VARIABLES" just plain? also log in as root, and do "SHOW GRANTS FOR " with the user you're logging in as? if theres a case where a logged in user can't see VARIABLES that is a new bug report.

[zzzeek]

issue created at https://bitbucket.org/zzzeek/sqlalchemy/issues/4007/mysql-57-may-have-made-show-variables as this looks like a regression due to changes in MySQL.

[Lupino]

$ mysql
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 9857
Server version: 5.7.18 Homebrew

Copyright (c) 2000, 2017, Oracle and/or its affiliates. All rights reserved.

Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

mysql> SHOW VARIABLES;
Empty set (0.00 sec)

mysql> SHOW GRANTS FOR;
ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '' at line 1
mysql>

[zzzeek]

resolved in 5650a0c