[Sugar-devel] Potential data loss problem in collaboration

[Sridhar Dhanapalan]

We have found a problem that could lead to data loss in the field.

General summary:

    A shares an activity
    B connects to A's shared instance
    Collaborative work is done by A and B
    A closes the activity
    B continues to work on the activity (maybe they didn't realise
that A has left)
    A shares again
    B connects
    Everything B has worked on since A left the first time is lost

This example uses the Write activity, but it can happen with any activity:

    A begins activity
    A types something (text is “AA” now)
    A shares the activity
    B joins activity
    B types something (text is “AABB” now)
    A closes activity (Text saved in A’s journal is AABB)
    B continues to write something (text is “AABBCC” now)
    B also closes activity (Text saved in B’s journal is AABBCC)
    Now B opens the same activity from B’s journal. B is able to see
the text AABBCC now.
    B closes the activity.
    Now A opens the activity from journal. Text is AABB now.
    A shares the activity again.
    B joins the activity from the neighbourhood view since it is
shared. Text in B’s XO is AABB now.
    A and B close the activity.
    Now when B opens the activity from the journal again, only AABB is
seen (text CC is lost).


Sridhar


Sridhar Dhanapalan
Technical Manager
One Laptop per Child Australia
M: +61 425 239 701
E: sridhar at laptop.org.au
A: G.P.O. Box 731
     Sydney, NSW 2001
W: www.laptop.org.au