got 'WrongSegmentError' during repair

[francois]

As I was working to improve the logging of 'tahoe deep-check' and 'tahoe check' (another ticket coming soon), I manually deleted shares from two different tahoe nodes to manually trigger a repair.

Encoding parameters of this file were M=66 and K=22.

The complete debug log as extracted by 'flogtool' is attached to this ticket.

$ tahoe check --repair URI:CHK:XXXXX
ERROR: 500 Internal Server Error
Traceback (most recent call last):
  File \"/usr/lib/pymodules/python2.6/foolscap/eventual.py\", line 26, in _turn
    cb(*args, **kwargs)
  File \"/home/francois/dev/tahoe-upstream/src/allmydata/immutable/downloader/node.py\", line 472, in _deliver
    d.callback(result) # might actually be an errback
  File \"/usr/lib/python2.6/dist-packages/twisted/internet/defer.py\", line 280, in callback
    self._startRunCallbacks(result)
  File \"/usr/lib/python2.6/dist-packages/twisted/internet/defer.py\", line 354, in _startRunCallbacks
    self._runCallbacks()
--- <exception caught here> ---
  File \"/usr/lib/python2.6/dist-packages/twisted/internet/defer.py\", line 371, in _runCallbacks
    self.result = callback(self.result, *args, **kw)
  File \"/home/francois/dev/tahoe-upstream/src/allmydata/immutable/downloader/segmentation.py\", line 116, in _got_segment
    raise WrongSegmentError(\"I was given the wrong data.\")
allmydata.immutable.downloader.common.WrongSegmentError: I was given the wrong data.

[warner]

(reformatted the 'tahoe check' output a bit for easier display)