'weakly-referenced object no longer exists' in mySQL

[janez]

I occasionally get the error below, but I am not able to reproduce it. It does not happen on a particular operation; when it occurs, the whole trac is down until I restart it.

Traceback (most recent call last):
  File "C:\Python23\Lib\site-packages\trac\web\main.py", line 406, in dispatch_request
    dispatcher.dispatch(req)
  File "C:\Python23\Lib\site-packages\trac\web\main.py", line 191, in dispatch
    chosen_handler = self._pre_process_request(req, chosen_handler)
  File "C:\Python23\Lib\site-packages\trac\web\main.py", line 263, in _pre_process_request
    chosen_handler = f.pre_process_request(req, chosen_handler)
  File "C:\Python23\lib\site-packages\trac\versioncontrol\api.py", line 73, in pre_process_request
    self.get_repository(req.authname).sync()
  File "C:\Python23\Lib\site-packages\trac\versioncontrol\cache.py", line 70, in sync
    cursor.execute("SELECT name, value FROM system WHERE name IN (%s)" %
  File "C:\Python23\Lib\site-packages\trac\db\util.py", line 51, in execute
    return self.cursor.execute(sql)
  File "C:\Python23\Lib\site-packages\trac\db\util.py", line 51, in execute
    return self.cursor.execute(sql)
  File "C:\Python23\lib\site-packages\MySQLdb\cursors.py", line 137, in execute
    self.errorhandler(self, exc, value)
  File "C:\Python23\lib\site-packages\MySQLdb\connections.py", line 33, in defaulterrorhandler
    raise errorclass, errorvalue
ReferenceError: weakly-referenced object no longer exists

I use standalone trac frontend on Windows 2003, with Python 2.3 and mySQL 4.1.22. I use mySQL from Python in other applications, so this should not be the problem. I cannot try it on a more recent version of Python or mySQL due to dependencies on other software installed on the server.

[cboos]

See #3645.

You should nevertheless be able to upgrade your MySQL python bindings, without having to upgrade MySQL itself, as it's a known bug in those bindings.