From: Brian Gernhardt Date: Mon, 07 Jul 2008 15:03:46 GMT Subject: Re: [FIXED PATCH] Make rebase save ORIG_HEAD if changing current branch Message-ID: In-Reply-To: On Jul 7, 2008, at 7:42 AM, Jakub Narebski wrote: > Theodore Tso writes: > >> True, but (and please correct me if I'm wrong) ORIG_HEAD will always >> be pointing out HEAD before the user typed pretty much any git >> porcelein command (which saves HEAD into ORIG_HEAD), but with >> reflogs, >> it you have to paw through multiple HEAD@{n} to find the 'n' which >> corresponds to state before executing the git plumbing command, since >> multiple git plumbing commands could have updated the HEAD's reflog, >> right? > > You can always use _branch_ reflog, either in the @{1} form, > or in @{1} shortcut form. @{1} should be equovalent to ORIG_HEAD > even for rebase. I personally expected @{1} to be identical to HEAD@{1}. Since omitting a ref usually refers to HEAD, why shouldn't omitting it when referring to the reflogs mean the HEAD log? The definition of @{1} is useful since there's no other easy way to get "current branch's reflog", but I think it's non-obvious. (Since HEAD@{1} is something completely different, I think the only other way to refer to @{1} is $ (git symbolic-ref)@{1}.) Also, your statement is only true if ORIG_HEAD was on the branch you are currently working. If we want ORIG_HEAD to mean "state of HEAD before last command", then "git rebase upstream topic" from master should leave ORIG_HEAD pointing to master, not topic@{1}. It also is no longer true if you switch branches. Having ORIG_HEAD set to the point before a pull is useful to compare multiple branches to both the old and new position of your updated branch. If we're going to have ORIG_HEAD set by _any_ command, we should probably come up with some consistent definition of it and set it appropriately. The first place most people encounter ORIG_HEAD is after a pull, where it acts something like a reverse of FETCH_HEAD (old state of local vs. new state of remote). However, pull only sets ORIG_HEAD by way of merge and reset sets ORIG_HEAD as well. So the current definition appears to be "the prior state of the last branch to be drastically changed." By this definition, ORIG_HEAD should be set by am and rebase as per Junio's patch. You could make an argument for removing ORIG_HEAD, it's functionality being replaced by the reflogs. At this point, it's a rather established bit of git, and I think has usefulness of it's own. ~~ Brian