[tahoe-lafs-trac-stream] [tahoe-lafs] #1669: ValueError (need more than 8 values to unpack) during mutable MDMF repair

[tahoe-lafs]

#1669: ValueError (need more than 8 values to unpack) during mutable MDMF repair
-------------------------+-------------------------------------------------
     Reporter:  vikarti  |      Owner:  zooko
         Type:  defect   |     Status:  assigned
     Priority:           |  Milestone:  1.9.2
  critical               |    Version:  1.9.1
    Component:  code-    |   Keywords:  mutable mdmf repair error
  mutable                |  regression preservation
   Resolution:           |
Launchpad Bug:           |
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Comment (by zooko):

 Update: I think that the only place the 8-tuple "verinfo" could get
 generated and passed around is
 [source:1.9.2/src/allmydata/mutable/servermap.py?rev=5482#L740 here].
 However, tracing backwards to see what could have led to that line of
 code, the only thing that can lead to that code is someone updating an
 MDMF by changing only part of it, and the only time that is ever done is
 if someone uses [source:1.9.2/docs/frontends/webapi.rst?rev=5469#writing-
 uploading-a-file the WAPI] to do so. I doubt that anything vikarti did,
 and certainly not a deep-check, was doing that, which leads me to think
 that the 8-tuple "verinfo" must have gotten generated and passed around in
 some other way.

 Aha! Then it must be the one other possibility --
 [source:1.9.2/src/allmydata/mutable/publish.py?rev=5481#L883 here]. That
 is called from exactly one place --
 [source:1.9.2/src/allmydata/mutable/publish.py?rev=5481#L856 here]. Which
 is called from exactly one place --
 [source:1.9.2/src/allmydata/mutable/publish.py?rev=5481#L764 here]. Which
 is called from exactly one place --
 [source:1.9.2/src/allmydata/mutable/publish.py?rev=5481#L616 here]. Which
 means that it is when a {{{Publish}}} object publishes the file's
 contents...

 Investigating a bit more...

-- 
Ticket URL: <https://tahoe-lafs.org/trac/tahoe-lafs/ticket/1669#comment:16>
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