IntegrityError: (1062, "Duplicate entry 'fzsk@sina.com' for key 'PRIMARY'")

[fezh]

How to Reproduce

While doing a POST operation on /login, Trac issued an internal error.

(please provide additional details here)

Request parameters:

{'__FORM_TOKEN': u'53cbad8d22a6488b58d06d2a', 'nick': u'fzsk', 'referer': u''}

User agent: Mozilla/5.0 (Windows NT 6.1; WOW64; Trident/7.0; SLCC2; .NET CLR 2.0.50727; .NET CLR 3.5.30729; .NET CLR 3.0.30729; Media Center PC 6.0; .NET4.0C; InfoPath.3; rv:11.0) like Gecko

System Information

System information not available

Enabled Plugins

Plugin information not available

Python Traceback

Traceback (most recent call last):
  File "/usr/lib/python2.6/site-packages/trac/web/main.py", line 513, in _dispatch_request
    dispatcher.dispatch(req)
  File "/usr/lib/python2.6/site-packages/trac/web/main.py", line 235, in dispatch
    resp = chosen_handler.process_request(req)
  File "/usr/lib/python2.6/site-packages/trac/web/auth.py", line 126, in process_request
    ret = self._do_login(req)
  File "/usr/lib/python2.6/site-packages/trac/web/auth.py", line 233, in _do_login
    @self.env.with_transaction()
  File "/usr/lib/python2.6/site-packages/trac/db/api.py", line 77, in transaction_wrapper
    fn(ldb)
  File "/usr/lib/python2.6/site-packages/trac/web/auth.py", line 238, in store_authnick
    (remote_user, nick))
  File "/usr/lib/python2.6/site-packages/trac/db/util.py", line 65, in execute
    return self.cursor.execute(sql_escape_percent(sql), args)
  File "/usr/lib64/python2.6/site-packages/MySQLdb/cursors.py", line 173, in execute
    self.errorhandler(self, exc, value)
  File "/usr/lib64/python2.6/site-packages/MySQLdb/connections.py", line 36, in defaulterrorhandler
    raise errorclass, errorvalue
IntegrityError: (1062, "Duplicate entry 'fzsk@sina.com' for key 'PRIMARY'")