[tahoe-lafs-trac-stream] [Tahoe-LAFS] #2814: "simultaneuous" edits not caught

[Tahoe-LAFS]

#2814: "simultaneuous" edits not caught
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 Reporter:  meejah                      |          Owner:  daira
     Type:  defect                      |         Status:  new
 Priority:  normal                      |      Milestone:  undecided
Component:  code-frontend-magic-folder  |        Version:  1.11.0
 Keywords:                              |  Launchpad Bug:
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 If two paired magic folders both edit (or create) the same file at "the
 same time" (i.e. before they learn of the other side's edit) then no
 conflict is detected (and the file is not synchronized between the two
 sides).

 I think what's happening is this (for the creation case, but same for a
 simultaneous edit):

 1. bob's uploader sees a new file called "foo" (locally created)
 2. alice's uploader sees a new file called "foo" (locally created)
 3. "foo" is not in the DMD for either Alice or Bob
 4. creates a new entry (version 0) and uploads
 5. whomever "wins" the upload, puts a "foo" of version 0 into the DMD
 6. the other side downloads the new DMD and sees a version 0 (and their
 local version is 0) so it decides "nothing to do".

 (p.s. there's two integration tests for this in the new branch I pushed
 recently for magic-folder integration tests)

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Ticket URL: <https://tahoe-lafs.org/trac/tahoe-lafs/ticket/2814>
Tahoe-LAFS <https://Tahoe-LAFS.org>
secure decentralized storage