fold: require --from flag for folding revisions to working copy It's very easy to think that "hg fold 4::6" will fold exactly those revisions. In reality, it will fold those *and* any revisions between them and the working copy. To prevent users from making that mistake, require the use of a new --from flag for folding revisions from the given set to the working copy. With this change, I'm sure some users will be surprised that the command can not be run without either --from or --exact, but at least the consequences will be smaller (the command simply aborts and the user can try again).