[Wikibots-l] WARNING! Running the bot more than once simultaneously can cause data loss!

Tue Oct 4 22:15:31 UTC 2005

There have been a few reports recently about the interwiki-bot
changing text that has nothing to do with interwikis. Checking those
cases, I can see that:
* The bot has made two edits to the same page in those cases; the
problematic edit is the second one, and
* The text being changed is actually the reverting of the last edit
before the first bot edit

I think that what is going on is this:
Someone is running the interwiki bot twice for some reason, and both
versions are working on the same page. Let's call the original text A,
with B being some other edit and C the bot's edit.

* Bot (version 1) loads the page (text A)
* Bot (version 2) loads the page (text A)
* Someone else changes the page to A+B
* Bot (version 1) submits the page (version A+C). The edit conflict is
correctly resolved by the MediaWiki software, and the page is saved as
A+B+C
* Bot (version 2) submits the page (version A+C). For some reason the
MediaWiki software does notice an edit conflict in this case, and the
page is saved as A+C, inadvertently reverting B.

I will be submitting this at Bugzilla, but for the time being I want
to issue the following warning:

Do NOT run the bot twice simultaneously UNLESS you are certain the two
runs will not be editing the same page.

--
Andre Engels, andreengels at gmail.com
ICQ: 6260644  --  Skype: a_engels