phil is kindly running ikiwiki on hands.com as http://rhombus-tech.net we continuously run into "merge" issues which need recovering on a near monthly basis.
i have a local checkout of the repository: i often need to upload images via that, doing the usual "git pull", followed by "git commit -a", followed by "git push", adding an HTML page that is edited by vim as well as the images.
i also often need to "recover" the wiki - for example by renaming pages that users have erroneously added, deleting pages that they should not have made, moving pages from locations that they should not have added or that i decide should be restructured.
these are the operations where everything usually gets completely fscked.
the really weird thing is that when i know that things are out-of-sync, a "git pull" gives a completely different head branch from the one shown through the RecentChanges log!
phil has often had to recover an entire set of files that are completely out of sync, that never enter the "git pull" stream onto my laptop, and are not visible on the wiki itself either.
this is all incredibly strange and mysterious, but it basically means that ikiwiki is not particularly robust and reliable for everyday use. i'd very much like it to be!