Needed: Scary patch tool

[Ben Elliston]

>>>>> "Michael" == Michael Still <mikal at stillhq.com> writes:

  >> > I have a version of some code which works, and a version which doesn't.
  >> > It's not my code, so I don't fully understand it. My plan is therefore to
  >> > do a diff between the two versions, and produce a patch.
  >> >
  >> > I would then like some what of applying each individual change in the
  >> > patch separately -- so that I can change a line at a time and see which
  >> > one introduced the breakage.

  Michael> I've already been using dirdif, which is cool (although I would like to
  Michael> see the whole files, not just the leading and trailing context). I was
  Michael> more after something which would help me apply portions of patch files --
  Michael> or am I not noticing a feature in dirdiff?

You should try emerge in Emacs.  You could start with the two files, A
and B.  Apply one patch from A into B and try it.  Rinse and repeat.

Ben