Hi,

I've installed Twisted 15.3.0 on Ubuntu 14.04LTS. Excellent work but there's one problem bothering me for a long time: twisted.mail.imap4.IMAP4Client.fetchMessage always throws exception and the exception occured at random, e.g. somtimes the exception occured when the program read the 120th mail, sometimes it occured at the 150th or 200th mail. The traceback of the exception is as follows:

Unhandled Error
Traceback (most recent call last):
  File "/usr/local/lib/python2.7/dist-packages/Twisted-15.3.0-py2.7-linux-i686.egg/twisted/python/log.py", line 101, in callWithLogger
    return callWithContext({"system": lp}, func, *args, **kw)
  File "/usr/local/lib/python2.7/dist-packages/Twisted-15.3.0-py2.7-linux-i686.egg/twisted/python/log.py", line 84, in callWithContext
    return context.call({ILogContext: newCtx}, func, *args, **kw)
  File "/usr/local/lib/python2.7/dist-packages/Twisted-15.3.0-py2.7-linux-i686.egg/twisted/python/context.py", line 118, in callWithContext
    return self.currentContext().callWithContext(ctx, func, *args, **kw)
  File "/usr/local/lib/python2.7/dist-packages/Twisted-15.3.0-py2.7-linux-i686.egg/twisted/python/context.py", line 81, in callWithContext
    return func(*args,**kw)
--- <exception caught here> ---
  File "/usr/local/lib/python2.7/dist-packages/Twisted-15.3.0-py2.7-linux-i686.egg/twisted/internet/posixbase.py", line 597, in _doReadOrWrite
    why = selectable.doRead()
  File "/usr/local/lib/python2.7/dist-packages/Twisted-15.3.0-py2.7-linux-i686.egg/twisted/internet/tcp.py", line 209, in doRead
    return self._dataReceived(data)
  File "/usr/local/lib/python2.7/dist-packages/Twisted-15.3.0-py2.7-linux-i686.egg/twisted/internet/tcp.py", line 215, in _dataReceived
    rval = self.protocol.dataReceived(data)
  File "/usr/local/lib/python2.7/dist-packages/Twisted-15.3.0-py2.7-linux-i686.egg/twisted/protocols/basic.py", line 571, in dataReceived
    why = self.lineReceived(line)
  File "/usr/local/lib/python2.7/dist-packages/Twisted-15.3.0-py2.7-linux-i686.egg/twisted/mail/imap4.py", line 2356, in lineReceived
    self._regularDispatch(line)
  File "/usr/local/lib/python2.7/dist-packages/Twisted-15.3.0-py2.7-linux-i686.egg/twisted/mail/imap4.py", line 2383, in _regularDispatch
    tag, rest = parts
exceptions.ValueError: need more than 1 value to unpack

My code is as simple as possible and the exception is thrown by the following codes:

dlist = []
for msg in messages:    # use message number, not UID
    d = self.fetchMessage(msg, uid=False)
    d.addCallback(cbGetAttachment)
    dlist.append(d)
dl = defer.DeferredList(dlist)
return dl.addCallback(cbLogout)

Is there anybody know about this issue?