So the other day I happened to need to back out some changes in my
xmonad.hs (I've been trying out sjanssen's monoid branch of
xmonad-core), and so I reverted it. Once I was done testing, I
unreverted. Or, at least I tried to.

I had made the mistake of doing 'revert xmonad.hs' and naively tried
to do 'unrevert xmonad.hs'. This didn't work:

 gwern@craft:39361~>revert .xmonad.hs
 Reverting changes in ".xmonad.hs"..

 There are no changes to revert!
 Finished reverting.
 gwern@craft:39360~>unrevert .xmonad.hs

 darcs failed:  Bad argument: `.xmonad.hs'
 Usage: darcs unrevert [OPTION]...
 Undo the last revert (may fail if changes after the revert).

 See darcs help unrevert for details.

(I eventually tried unrevert with no arguments, and had to manually
select the changes to xmonad.hs.) Now, personally, I think unrevert
should take a file argument since it makes just as much sense as for
revert. It is consistent, and desirable from a UI standpoint anyway.

This just hit me too, I'll look into it. The inconsistency between
revert/unrevert is annoying. (Though in my case, I did a "revert -a"
rather than a revert with a path, which is why I needed to selectively
unrevert)