rvdiffto parameter implementation

Sorry for the slow slow slow sloooow response.

I think diffs are a useful thing to have, but I'm not quite sure what the goal here is - what is the advantage of using rvdiffto instead of getting both revisions and comparing them with a python diff function?

I can see the use case for, for instance, an antivandalism bot, but I'm not quite sure how you would use it with this.

Then on the implementation - I can imagine it makes sense to store diffs for a certain revision, but I'd expect, for instance, a dict with revid's such that

page, revid=10001
diffs = \{10000: <diff object between 10000 and 10001>, 9000: <diff object between 9000 and 10001>\}, and storing e.g. revision.prev = 10000.

housekeeper's note:the patch does not apply cleanly to r10035

I do not think we should go with this.

Since the patch is really old and lots of changes made to base repo, the whole patch needs to be rewritten. Personally I think it's cool to have something like this

Any idea who created this patch. sf.net just says 'Anonymous' ;-(

Related: we now have a module pywikibot.diff which could be used to do the diff client site.