Feature summary:

A Special:Diff link with parameters, like /wiki/Special:Diff/123456?foo=bar, should redirect to /w/index.php?diff=123456&foo=bar intead of just /w/index.php?diff=123456. I'm not sure if this was the case before.

Use case(s):

I have a script that detects diff links and loads diffs in-place. Before loading, it adds a few parameters to the URL, like action=render, diffonly=1, unhide=1 and bot, for optimization and convenience. It would be nice if MediaWiki could preserve these.

Benefits:

See intended use case.