Tahoe operations fail with "no attribute _writekey" exception

[[4-tea-2]]

My weekly cronjobs ("deep-check --repair" and "backup") started failing two days ago. Upgrading to the latest Debian package (allmydata-tahoe_1.4.1-r3916_all.deb) did not help, the problem persists.

Example output from the cli (this is from allmydata-tahoe_1.4.1_all.deb, ie. pre-update):

$ tahoe deep-check --repair media: ERROR: AttributeError?(MutableFileNode? instance has no attribute '_writekey') [Failure instance: Traceback: <type 'exceptions.AttributeError?'>: MutableFileNode? instance has no attribute '_writekey' /usr/lib/python2.5/site-packages/twisted/internet/base.py:705:runUntilCurrent /usr/lib/python2.5/site-packages/foolscap/eventual.py:26:_turn /usr/lib/python2.5/site-packages/twisted/internet/defer.py:243:callback /usr/lib/python2.5/site-packages/twisted/internet/defer.py:312:_startRunCallbacks --- <exception caught here> --- /usr/lib/python2.5/site-packages/twisted/internet/defer.py:328:_runCallbacks /usr/lib/python2.5/site-packages/allmydata/mutable/checker.py:301:_maybe_repair /usr/lib/python2.5/site-packages/allmydata/mutable/filenode.py:263:repair /usr/lib/python2.5/site-packages/allmydata/mutable/repairer.py:89:start /usr/lib/python2.5/site-packages/allmydata/mutable/filenode.py:172:get_writekey

Output from allmydata-tahoe_1.4.1-r3916_all.deb is identical, up to the line numbers.

Running "deepcheck-and-repair" from the WUI results in the same exception, yet no incident report is created. I'll attach the HTML output of the result page (after clicking "reload").

[[4-tea-2]]

HTML output of exception after deepcheck-and-repair

[warner]

This is probably another instance of #625, unfortunately.

[davidsarah]

It's clear from the traceback that this is a duplicate of #625.