Re: [RFC 1/4] Add diff-diff, which compares the diffs of two commits

Steffen Prohaska [off-list ref] writes:

At this point, I'm only seeking comments about the general direction.
The patches should not be applied to git.git.

 - Do you think something like this would be helpful?
 - Are similar approaches already available?
 - How do you use git to support code review; besides discussing
   patches on mailing lists?

I think there are other good building blocks you can use outside git to
help reviewing evolution of patches (interdiff comes to mind).

When I receive a replacement series to a topic, I use RP script
(available in my 'todo' branch and checked out in Meta/ directory in my
work area, together with other scripts from 'todo'), which:

 * finds where the older series were applied;
 * detaches HEAD at that commit, and apply the new series;
 * runs diff between the old and new;
 * updates the tip of that topic with the new series.

After it finishes, "diff topic@{1} topic" becomes the incremental diff
between the old and the new series, and if I do not like the end result,
I can reset --hard back to topic@{1}.