[Python] "_mysql was already imported" error

Can you explain what is causing this error?

[PHP]% cat test.py #!/usr/bin/env python import MySQLdb import matplotlib % test.py /usr/lib/python2.5/site-packages/pytz/__init__.py:29: UserWarning: Module _mysql was already imported from /var/lib/python-support/python2.5/_mysql.so, but /var/lib/python-support/python2.5 is being added to sys.path from pkg_resources import resource_stream [/PHP] But if I switch the order of the imports, the error goes away: [PHP]% cat test.py #!/usr/bin/env python import matplotlib import MySQLdb % test.py % [/PHP] This is occurring on a fresh Intrepid install. I tried googling "_mysql was already imported" for an answer, but came up empty.

[PHP] % apt-cache policy python-matplotlib python-matplotlib: Installed: 0.98.3-4ubuntu1

% apt-cache policy python-mysqldb python-mysqldb: Installed: 1.2.2-7[/PHP]

It would appear that matplotlib imports mySQLdb and that it does it in a manner that a message is issued if mySQLdb already is imported.

If it's an issue, I'd have a look into the initialization of matplotlib, particularly into the method __init__ of the class pytz which is named in the warning message.

Thanks, pp., but I'm still confused.

If you have python-mysqldb and python-matplotlib installed, can you reproduce the same error?

For one thing, python-matplotlib does not list mysql as a dependency.

Is matplotlib or mysqldb importing pytz? I haven't been able to track down where this is happening.

• As far as I can tell, matplotlib does not import _mysql.
• Isn't it true that packages can be imported repeatedly with no adverse consequence? If so, why should pytz throw a UserWarning about this?
• /usr/lib/python2.5/site-packages/pytz has to do with timezones.

Thank you for your time and thought. I'd greatly appreciate any additional help you can give.

Perhaps it would be useful to study this file, particularly line 29:

/usr/lib/python2.5/site-packages/pytz/__init__.py:29

I managed to make the warning go away by editing /usr/lib/python2.5/site-packages/pkg_resources.py:

I changed line 2272:

From:[PHP] if fn and normalize_path(fn).startswith(loc):[/PHP]

To:[PHP] if fn and (fn.startswith(loc) or normalize_path(fn).startswith(loc)):[/PHP]

Thanks for your help, pp.!

unutbu said: Thanks for your help, pp.!

You're welcome, but I suggest to read this thread again: All I did was to selectively quote the error message to you which you included in your first post. There's a lesson somewhere hidden.