Thien-Thi Nguyen : > So, i think "rollback" as a concept is actually not far > enough. Being able to select arbitrary commits to drop (like > ‘d’ and ‘x’ in Dired) is what i'd like to see, in its stead. RCCS and SCCS can do this, in theory. But I've never trusted that feature. The obvious problem is that if you delete an earlier delta you may well change the preconditions for a later one, so it will have unexpected effects. I know how RCS's delta representation works; it is *not* smart enough to fully compensate. And no wonder. General patch composition is a hard enough problem that it scuttled Darcs thirty years later! In other VCSes it would be difficult to even attempt this. In view of the known problems, I recommend staying way the hell away from it unless and until David Roundy successfully proves a correct composition algorithm and we integrate it into Emacs somehow. -- Eric S. Raymond