OOPS when uploading with dput-ng

[Colin Watson]

Attempting to upload a package with dput-ng causes an OOPS, reproduced on dogfood as follows:

Traceback (most recent call last):
  File "/srv/launchpad.net/codelines/lp-sourcedeps/eggs/Twisted-13.0.0-py2.7-linux-x86_64.egg/twisted/conch/ssh/filetransfer.py", line 53, in dataReceived
    f(data)
  File "/srv/launchpad.net/codelines/lp-sourcedeps/eggs/Twisted-13.0.0-py2.7-linux-x86_64.egg/twisted/conch/ssh/filetransfer.py", line 322, in packet_STAT
    d.addCallback(self._cbStat, requestId)
  File "/srv/launchpad.net/codelines/lp-sourcedeps/eggs/Twisted-13.0.0-py2.7-linux-x86_64.egg/twisted/internet/defer.py", line 304, in addCallback
    callbackKeywords=kw)
  File "/srv/launchpad.net/codelines/lp-sourcedeps/eggs/Twisted-13.0.0-py2.7-linux-x86_64.egg/twisted/internet/defer.py", line 293, in addCallbacks
    self._runCallbacks()
--- <exception caught here> ---
  File "/srv/launchpad.net/codelines/lp-sourcedeps/eggs/Twisted-13.0.0-py2.7-linux-x86_64.egg/twisted/internet/defer.py", line 575, in _runCallbacks
    current.result = callback(current.result, *args, **kw)
  File "/srv/launchpad.net/codelines/lp-sourcedeps/eggs/Twisted-13.0.0-py2.7-linux-x86_64.egg/twisted/conch/ssh/filetransfer.py", line 343, in _cbStat
    data = requestId + self._packAttributes(result)
  File "/srv/launchpad.net/codelines/lp-sourcedeps/eggs/Twisted-13.0.0-py2.7-linux-x86_64.egg/twisted/conch/ssh/filetransfer.py", line 94, in _packAttributes
    if 'size' in attrs:
exceptions.TypeError: argument of type 'NoneType' is not iterable

This would appear to combine with https://bugs.launchpad.net/txpkgupload/+bug/906211 to cause the memory allocation death-spirals we've encountered over the last couple of days.

[Colin Watson (cjwatson)]

I think rather than firewalling issues the death-spiral was actually due to https://code.launchpad.net/~cjwatson/lp-production-configs/txpkgupload-errors/+merge/247442.